Road Guide to the Geology of the Uinta Mountains by bmo99796

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									                 Road Guide to the Geology of the Uinta Mountains
            for the 2005 Utah Geological Association Field Conference
                    Douglas A. Sprinkel*, Bart J. Kowallis†, Joel L. Pederson‡, and Carol M. Dehler‡



    The 2005 UGA field conference will focus on the geology of the Uinta Mountains. The three-day field
conference will examine the geology along the south flank of the Uintas from Kamas to Vernal on the first
day. The second day we will travel from Vernal over the Diamond Mountain Plateau in the eastern Uintas
into Browns Park. The last stop on the second day will be in Sheep Creek Canyon before traveling back to
Salt Lake City. On the final day we will loop through the western Uinta Mountains over the Mirror Lake
Scenic Byway (SR 150) and the North Slope road from near the Bear River Ranger Station to Mountain
View, Wyoming.

                    GE OLO GI C D E S CRI PTION OF THE SOUTH F L ANK OF THE
                                         UINTA MOUNTAINS
                               FRO M S A LT L AKE C ITY TO VERNAL

DAY 1 – The first day of the 2005 UGA field conference will travel from Salt Lake City to Vernal along
the south flank of the Uinta Mountains (figure 1.1). The route follows Parleys Canyon on I-80 to U.S. 40.
From there, the route will travel through Kamas and over the southwest flank of the Uinta Mountains on
SR 35 and wind its way across the Uinta Basin to Vernal. Along the way, the route will travel into the Uinta
Mountains along the Duchesne River, Lake Fork River, and the Mosby Mountain area (between Whiterocks
River and Dry Fork). The geology along the way includes good exposures of Red Pine Shale of the Uinta
Mountain Group, Madison Limestone, a number of Mesozoic fortmations (figures 1.2 and 1.3). Some of
the best examples of several ages of glacial deposits are preserved along the route. The route travels across
the trace of the South Flank fault and associated northwest-southeast-trending normal and oblique slip
faults.

MI LE A G E        D E S CRI PTI O N
(CUMULATIVE/ INCREMENT)

0.0      0.0       Start at the Department of Natural Resources (DNR) building (1954 W. North Temple, Salt
                   Lake City) at 7:30 am. Leave the DNR building by turning left on North Temple to Redwood
                   Road to access I-80 east. Turn left on Redwood Road to the I-80 eastbound entrance. Travel
                   east on I-80 to I-15 south.

4.7      4.7       Intersection of I-80 and I-15; take I-80 East to Cheyenne and cross Salt Lake Valley on Lake
                   Bonneville deposits and modern alluvium.

10.5     5.8       Cross Wasatch fault onto footwall. The mouth of Parleys Canyon has the Triassic Ankareh


*Utah Geological Survey, Salt Lake City, Utah 84114          Sprinkel, D.A., Kowallis, B,J., Pederson, J.L., and Dehler, C.M., 2005,
douglassprinkel@utah.gov                                     Geologic road guide to the geology of the Uinta Mountains for the 2005
†Brigham Young University, Provo, Utah 84602                 Utah Geological Association field conference, in Dehler, C.M., Pederson,
‡Utah State University, Logan, Utah 84322                    J.L., Sprinkel, D.A., and Kowallis, B.J., editors, Uinta Mountain geology:
                                                             Utah Geological Association Publication 33, p. 397-448.

                                                         397
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                                                                                                                                                                     Road Guide to the Geology of the Uinta Mountains for the 2005 UGA Field Conference




      Figure 1.1. Index map of the Uinta Mountains and surrounding area showing the field conference stops for Day 1. This map provides only a general perspective
      of the stops and a detailed road and/or topographic map to follow road guide directions.
                                                                                                                                                                      B,J. Kowallis, D.A. Sprinkel, J.L. Pederson, and C.M.
Dehler, Pederson, Sprinkel, and Kowallis, editors                                                            2005 Utah Geological Association Publication 33


                                 WESTERN      WEST-CENTRAL    EAST-CENTRAL       EASTERN     RANGE OF KNOWN OCCURENCE
                                                                                              OF FOSSILS AND LOCATION OF
                             UINTA MOUNTAINS UINTA MOUNTAINS UINTA MOUNTAINS UINTA MOUNTAINS     RADIOMETRIC SAMPLE
 Paleozoic



                  M          Deseret Formation                   Madison Limestone
                      360
                  C            Tintic Quartzite                                        Lodore Sandstone
                      543
                  L
                      630
 NEOPROTEROZOIC




                      740
                                            Red Pine Shale




                                                                                                                         770 Ma, U-Pb detrital zircon
                  M




                                                                                                                                                                                                                                                                 Eohyella sp.
                                                                                                                                                                                                                                                                                Bavlinella faveolata
                                                                                                                                                                                                                                                                                                       Chuaria
                  I                           formation of Hades Pass
                  D
                  D                                                                             formation
                  L          Mount Watson                                                          of
                  E           Formation formation of
                                                                                             Crouse Canyon
                                           Dead Horse    formation of Red Castle
                                              Pass




                                                                                                                                                                                                                                 Trachysphaeridium laminaritum
                                                                                                                                                                                                                                         Eossacharomyces sp.
                                                                                             formation of Outlaw Trail

                                                                                                 formation of
                                                                                                                         *
                                formation of
                                                                                               Diamond Breaks
                                                                                                                                                        ?
                               Moosehorn Lake




                                                                                                                                                        v-shaped microfossils
                                                                                                Jesse Ewing
                              undivided unit             ?                   ?




                                                                                                                                                                                algal filament fragments

                                                                                                                                                                                                           Leiosphaeridia spp.
                                                                                              Canyon Formation
                      850
                  E   1000
 MESO-
PROTERO-              1600
  ZOIC
 PROTEROZOIC




                                                                    Red Creek Quartzite(?)   Red Creek Quartzite
   ARCHEAN




                                  Little Willow
    EARLY

     AND




                                   Formation             ?                  and                     and
                                                                    Owiyukuts Complex(?)     Owiyukuts Complex
                      2500

 Figure 1.2. Stratigraphic chart of the Uinta Mountain Group showing tentative correlations of its formations across the
 Uinta Mountains and paleontologic and radiometric data. This chart is based on the continued work by Carol Dehler,
 Doug Sprinkel, Susannah Porter, and Jerry Waanders. Stratigraphic nomenclature is from Wallace (1972), Sanderson
 (1984), Sanderson and Wiley (1986), and De Grey and Dehler (this volume). Paleontology and radiometric data is from
 Horodyski (1993), Fanning and Dehler (2005), Dehler and others (in press), and Sprinkel and Waanders (this volume).
 Distribution of formations based on mapping by Bryant (1992), Sprinkel (2002), and De Grey (2005).

                                 Formation on south side of canyon and the Jurassic Nugget on the north. The rocks strike
                                 north to northeast and dip steeply west. Overlying the Jurassic Nugget is the Jurassic Twin
                                 Creek Limestone. Much of I-80 from near the mouth of Parleys Canyon to Mountain Dell
                                 Reservoir travels across the Twin Creek Limestone. From Mountain Dell Reservoir to Lambs
                                 Canyon, I-80 travels across basal part of the Preuss Sandstone covered by surficial deposits.
                                 Numerous landslides are obvious along the interstate.

21.8                  11.3       Parleys Summit in Preuss Sandstone.

26.5                  4.7        Kimball Junction Exit. Note ski jumps on right (south) from the 2002 Winter Olympics. The
                                 ski jumps are cut into a hill of Mesozoic strata.

29.4                  2.9        Take U.S. 40 south to Heber City and Vernal.

33.1                  3.7        Take exit 4 to Park City and Kamas.


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                                        SOUTH FLANK UINTA MOUNTAINS                                    NORTH FLANK UINTA MOUNTAINS
                                          WESTERN        EASTERN                                         WESTERN        EASTERN

            Quaternary                           Glacial and surficial deposits                                 Glacial and surficial deposits
             Pliocene                                 Alluvial-gravel deposits                                     Alluvial-gravel deposits
             Miocene                                                                                                                  Browns Park Formation

            Oligocene                                 Bishop Conglomerate                                           Bishop Conglomerate
                                                        Duchesne River Formation                                                     Bridger Formation
             Eocene               Keetley Volcanics         Uinta Formation
                                                                                                                                   Green River Formation
                                                         Green River Formation
            Paleocene                                      Wasatch Formation                          Echo Canyon Conglomerate
                                                                                                                                    Wasatch Formation
                                                           Mesaverde Group                           Evanston-Henefer Formations          Mesaverde Group
                                                             Mancos Shale                                    Hilliard Shale                  Baxter Shale
                                                           Frontier Sandstone                             Frontier Sandstone              Frontier Sandstone
                                                                                                             Aspen Shale                     Mowry Shale
            Cretaceous                                        Mowry Shale
                                                           Dakota Sandstone                               Dakota Sandstone                Dakota Sandstone

                                                Cedar Mountain Formation                                Kelvin Formation           Cedar Mountain Formation
                                                   Morrison Formation                                               Morrison Formation
               Jurassic               Preuss Sandstone                    Stump Formation             Preuss Sandstone               Stump Formation
                                       Stump Formation                                                 Stump Formation
                                                                          Carmel Formation                                           Carmel Formation
                                     Twin Creek Limestone                                            Twin Creek Limestone
                                      Nugget Sandstone                    Nugget Sandstone            Nugget Sandstone               Nugget Sandstone

                                  Ankareh Formation                                                 Ankareh Formation
               Triassic                                 Chinle Formation                                                  Chinle Formation
                                  Thaynes Limestone                                                 Thaynes Limestone
                                                      Moenkopi Formation                                                Moenkopi Formation
                                  Woodside Formation                                                Woodside Formation
               Permian                Park City-Phosphoria Formation                                    Park City-Phosphoria Formation

                                                   Weber Sandstone                                               Weber Sandstone
          Pennsylvanian                            Morgan Formation                                              Morgan Formation
                                                 Round Valley Limestone                                        Round Valley Limestone

                                  Doughnut Formation            Doughnut Formation                                  Doughnut Formation
                                  Humbug Formation
           Mississippian           Deseret Limestone            Humbug Formation                                    Humbug Formation
                                  Gardison Limestone            Madison Limestone                                   Madison Limestone
              Devonian
               Silurain
              Ordovician
                                                                                     Diabase dikes Diabase dikes
             Cambrian                  Tintic Quartzite                    Lodore Sandstone          Tintic Quartzite                 Lodore Sandstone

 Figure 1.3. Stratigraphic nomenclature chart of Phanerozoic rocks in the Uinta Mountains and margins of Green River
 and Uinta Basins (Rowley, 1985; Bryant, 1992; Sprinkel, 2002).


33.4     0.3       Turn left at the bottom of the exit and travel east on SR 248. Road cuts along SR 248
                   are in Keetley Volcanics. The Keetley Volcanics are heterogeneous mix of lahar, flow breccia
                   and tuff with an age range of 36.0 +/- 3.8 to 32.7 +/- 1.0 m.y. (Crittenden and others, 1973;
                   Bryant and others, 1989; Bryant, 1990). Bryant and others (1989) indicate that “intrusions
                   presumed to be feeders for the Keetley volcanic field are aligned along and west of the trend of
                   the Uinta Mountains,” suggesting that the structures controlling formation of the mountains
                   also helped localize the volcanic and intrusive activity.

40.0     6.6       Summit County line.

43.1     3.1       Turn right on Spring Meadow Way.

43.4     0.3       Turn left on 200 south and proceed east.

43.5     0.1       STOP 1- View of Kamas Valley. Discuss nose of Uinta Mountains and drainage divide along
                   with the histories of the Weber and Provo Rivers and general geology. Also discuss structure
                   from Precambrian through Paleozoic time, the Tooele arch, and mineralization of Park City
                   and Bingham mining districts.
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44.2      0.7       Turn right onto SR 248 we travel east to Kamas.

45.2      1.0       Intersection of SR 248 and SR 32. Turn right on SR 32 and travel south to Francis, Utah.

47.2      2.0       Francis, Utah; turn left onto SR 35 and travel east to Woodland, Utah.

50.5      3.3       Pleistocene river gravels on left in road cut.

51.3      0.8       Woodland, Utah, along Provo River.

52.8      1.5       Weber Sandstone in road cut on left.

54.8      2.0       Morgan Formation exposed in road cut on left.

57.4      1.1       STOP 2 - After crossing Provo River pull off on road side to discuss Quaternary history,
                    stream capture of the Provo River here at Pine Valley (Hansen, 1975), and south flank fault.
                    Provo River and road below are on Smiths Fork till and the higher gravel deposits are likely
                    Blacks Fork Till. The Madison Limestone is exposed along the west bank of the Provo River.

58.5      1.1       Madison Limestone road cut on left.

59.6      1.1       Noblets parking area. The parking area is along part of the toe of a large landslide complex.
                    Restrooms are available here.

60.1      0.5       STOP 3 – South Flank fault and landslide complex. The South Flank fault places Weber
                    Sandstone down on south next to Pennsylvanian Morgan Formation; the fault is not well
                    exposed from here but roughly parallels the change in vegetation. The South Flank fault trends
                    approximately east-west and runs along almost the entire length of the Uinta Mountains. The
                    fault has been mapped as both a normal and a reverse fault. At a location near Ice Cave Peak,
                    an exposed slip surface contains two sets of slickenlines. One set shows normal slip and the
                    second strike-slip (see Haddox and others, this volume).

                    The toe of a large landslide complex is east of road. The landslide is mostly failed Mississippian
                    Doughnut Formation, which contains clay-rich shale, sandstone, limestone, and some coal.
                    Note the limestone blocks and large pipes used to hold back and drain the slope to minimize
                    movement.

                    Much of the north-facing hillsides are covered with angular regolith and colluvium of Weber
                    Sandstone much of which is likely the result of periglacial weathering in the Pleistocene.

62.0      1.9       Cross South Fork of Provo River and the margin of landslide complex.

63.4      1.4       Weber Sandstone is exposed in road cut.

65.7      2.3       Soapstone Basin turn off; keep on SR 35.

66.9      1.2       Wolf Creek Pass and campground. The road travels across The Tertiary Keetley Volcanics at
                    the pass.

68.2      1.3       Outcrops of Triassic Thaynes Limestone.
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Road Guide to the Geology of the Uinta Mountains for the 2005 UGA Field Conference   B,J. Kowallis, D.A. Sprinkel, J.L. Pederson, and C.M.



69.0     0.8       Outcrop of Park City Formation in road cut on the left.

70.1     1.1       Weber Sandstone exposed in road cut on left.

73.6     3.5       Woodside shale in road cut on left with Thaynes Limestone capping the ridge on right.

73.8     0.2       Park City-Phosphoria Formations in road cut on the left.

73.9     0.1       Weber Sandstone in road cut on left.

74.7     0.8       Forest Service Boundary, Uinta National Forest. The road travels on the Park City Formation
                   with the Woodside Shale forming red slopes on right. The Thaynes Limestone caps the ridge.
                   A landslide brings the Thaynes Limestone down close to valley bottom.

76.2     1.5       Woodside Shale is in road cut on left.

77.3     1.1       Park City Formation in road cut on left contains a few small faults. The North Fork of the
                   Duchesne River parallels road on right.

77.8     0.5       Weber Sandstone in road cut on left.

78.1     0.3       Cross Duchesne River.

79.2     1.1       Turn left on road up Duchesne River drainage.

79.8     0.6       Smiths Fork moraine along both sides of road. On the left is the Round Valley Limestone
                   low in the slope with Morgan Formation mostly covered on left. The Weber Sandstone caps
                   ridge. On the right is Pennsylvanian-Permian Weber Sandstone underlain by Pennsylvanian
                   Morgan Formation (red color). The Mississippian Madison Limestone is seen up canyon. A
                   large landside (failed Mississippian Doughnut Formation) covers the valley (figure 1.4). An
                   apparent fault placed the Morgan Formation down next to the Madison Limestone.

80.7     0.9       Road is along toe of landslide. Madison Limestone forms on bold cliffs on right. Note the
                   karst development typical in the Madison and the small fold. The folds are possible fault-tip
                   folds.

82.6     1.9       Tintic Quartzite in road cut on right.

82.8     0.2       Red Pine Shale outcrops.

83.4     0.6       STOP 4 – Paleotopography developed on the Red Pine Shale of the Uinta Mountain Group.
                   Here the Cambrian Tintic Quartzite dramatically thins and pinches out over this paleohigh in
                   the Red Pine Shale. Up the canyon, the Mississippian Madison Formation sits directly on the
                   Neoproterozoic Red Pine Shale. Discuss facies, paleontology, and depositional environments
                   of the Red Pine.

84.9     1.5       The Red Pine Shale contains numerous thick sandstone beds. Note Red Pine sandstone and
                   siltstone beds forming low cliff along west side of Duchesne River.

85.7     0.8       Road junction to Grand View trail head to the Granddaddy Lakes area. Continue on road to
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                     Iron Mine campground.

86.3      0.6       Cattle guard. Good exposures of the
                    Red Pine Shale. Note thick interval
                    of stacked channel sandstones.
                    These likely represent a delta plain
                    depositional setting.

87.0      0.7       STOP 5 – Iron Mine campground and
                    Iron Mine Canyon. The South Flank
                    fault cuts up Iron Mine Canyon and
                    placed the Red Pine Shale down on the
                    south next to the Hades Pass Formation Figure 1.4. Landslide that has moved into the glaciated
                    of the Uinta Mountain Group. Several valley of the Duchesne River drainage. The failure heads
                    zones of mineralization along the in a strike valley of the Mississippian Doughnut Forma-
                    South Flank fault have prompted tion. The rocks dip moderately southeast. View is north.
                    exploration and some mining. See
                    Conn’s paper in this volume for a
                    detailed discussion of the Iron Mine
                    and Nelson and others, this volume for a discussion of other mineralization along the South
                    Flank fault. Turn around and head down canyon to SR 35.

91.4      4.0       Stone face is in Tintic Quartzite.

94.7      3.3       Junction of SR 35. Turn left to Hanna. The valley and road travels through the Weber
                    Sandstone and then through Nugget Sandstone. Small fault placed Triassic Woodside Shale
                    down next to Pennsylvanian-Permian Weber Sandstone.

99.1      4.4       STOP 6 (The Mesa) – Twin Creek Limestone. Discuss Jurassic Nugget Sandstone and Twin
                    Creek stratigraphy. Point out landslides on flank of Tabby Mountain and the flat top of Tabby
                    Mountain, which has Oligocene Bishop Conglomerate deposited on the Gilbert Peak erosion
                    surface.

100.4 1.3           Hanna.

103.7 3.3           Leaving Hanna the road continues up section through the Cretaceous and lower Tertiary
                    strata. On the right in a large landslide on Tabby Mountain with summer homes built on it.

104.8 1.1           Tabiona.

107.9 3.1           Intersection of SR 35 and SR 208. Continue east on SR 35. The Duchesne River Formation
                    crops out on both sides of the road.

116.1 8.2           The road has cut down through Duchesne River Formation into the underlying Uinta Formation.
                    The contact is on the juniper-covered bench on the left. The Duchesne River Formation is
                    generally redder and coarser compared to the Uinta Formation, which is generally light-
                    colored and contains more clay-rich mudstone. Note the oil wells of the western extent of
                    the Altamont-Bluebell field.

123.5 7.4           Road travels up to the top of Blue Bench. The Uinta Formation crops out on left. Blue Bench
                    is capped by terrace gravels deposited by the Duchesne River.
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Road Guide to the Geology of the Uinta Mountains for the 2005 UGA Field Conference   B,J. Kowallis, D.A. Sprinkel, J.L. Pederson, and C.M.



124.9 1.4          Turn left on SR 87 to Moon Lake.

128.3 3.4          Duchesne River Formation in road cuts.

132.3 4.0          Talmage, continue north on SR 87.

134.0 1.7          Duchesne River Formation is well exposed in hairpin.

134.5 0.5          Turn left on road 1566 to Moon Lake. The road crosses over Duchesne River Formation and
                   climbs up on benches of glacial outwash.

137.3 2.8          Intersection of Rock Creek road. Continue north to Moon Lake.

138.1 0.8          Turn right.

140.5 2.4          Pre-Blacks Fork (mid-Pleistocene) outwash with small hummocks of pre-Blacks Fork till to
                   the right.

142.1 1.6          The road is on the Smiths Fork outwash (age?) with hills to right composed of Blacks Fork
                   till.

144.5 1.1          Cut through Blacks Fork moraine.

144.9 0.4          Smiths Fork moraines.

150.5 5.6          Raspberry Draw. Landslide on right is within the Doughnut Formation.

151.2 0.7          Madison Limestone Cliffs or right.

151.5 0.3          Cattle guard at Moon Lake sign.

152.4 0.9          Lunch Stop – Moon Lake Group area A. After lunch turn around and return to Mountain
                   Home.

157.5 5.1          STOP 7 (Forest service boundary with Ute Tribal Land) – Twin Pots overlook. Take
                   short hike along Forest Service side of fence to an overlook to view glacial geology. Till and
                   outwash deposits of three ages are preserved; the oldest and highest is the pre-Blacks Fork
                   till, the intermediate level is Blacks Fork till and outwash, and the youngest is the Smiths
                   Fork till (figure 1.5). The bedrock unit to the east is the Nugget Sandstone. View erosion
                   surface (figure 1.6) with Triassic Moenkopi dipping steeply and underlying the gently dipping
                   Duchesne River Formation (possibly Starr Flat Member).

167.4 9.9          Junction with Rock Creek road, continue south on Route 1566.

170.3 2.9          Junction of SR 87. Turn left on SR 87. Road travels on outwash surfaces and gravelly
                   alluvium.

174.2 0.1          Bridge over branch of Lake Fork Creek

174.3 0.1          Bridge over branch of Lake Fork Creek.
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                                                                 Figure 1.6. View east of an unconformity near the mouth
                                                                 of Lake Fork River, east of Twin Pots. The rocks below the
                                                                 unconformity are dipping moderately steeply, which records
                                                                 uplift of the Uinta Mountains during the Laramide orogeny.
 Figure 1.5. View south of glacial deposits in Lake Fork         The unconformity and overlying rocks are also dipping south,
 River drainage, south of Moon Lake; Qgpb = pre-Blacks           but at a lower angle, which records some post Duchesne River
 Fork till, Qgb = Blacks Fork till and outwash, Qgs =            Formation uplift of the Uinta Mountains during the waning
 Smiths Fork till.                                               stages of the Laramide orogeny; Pp = Park City Formation,
                                                                 T m = Moenkopi Formation, Td = Duchesne River Formation.
                                                                  R




174.6 0.3           Climb up to gravel surface of Blacks Fork(?) outwash deposit.

175.6 1.0           Altamont. Continue east on SR 87. Altamont is built on pre-Blacks Fork gravels.

176.5 0.9           Continue right on SR 87. The pumping units scattered about the landscape are part of the
                    giant Altamont-Bluebell field, which now extends further west to include the Cedar Rim field
                    (Morgan, 2003). These three contiguous fields have produced more than 287 million barrels
                    of oil and more than 489 billion cubic feet of gas from 574 active well as of March 2005 (Utah
                    Division of Oil, Gas, and Mining records, 2005). Production is from multiple horizons in the
                    Tertiary Wasatch and Green River formations at depths that range from about 8500 to 12,500
                    feet (Smouse, 1993). The productive reservoirs include lacustrine sandstone, limestone,
                    and dolomite with porosities ranging from 2% to 20% and permeabilities as much 1000
                    millidarcies (Smouse, 1993). Smouse (1993) also reports the API gravity of oil produced
                    from the Wasatch Formation is 38o to 45o and from the Green River formation is 30o to 37o.

180.1 3.6           Road cut of Duchesne River Formation on left.

181.4 1.3           Big Sand Wash Reservoir. The reservoir is in Duchesne River Formation.

183.0 1.6           Upalco, continue south on SR 87. From Upalco to Ioka, the road swings to the east. The hills
                    to the south are Uinta Formation and the hills to the north are Duchesne River Formation. The
                    contact is near the base of the hills on the north and is marked by the dominant light-colored
                    mudstone of Uinta Formation and dominant red-colored Duchesne River Formation.

192.8 9.8           Junction with U.S. 40, turn left and travel to Roosevelt. The hills to left are Uinta Formation
                    and hills to the right are Duchesne River Formation.

194.7 1.9           Roosevelt City limit. The Duchesne River Formation crops out along U.S. 40 and in Roosevelt.
                    The contact with the underlying Uinta Formation is in subsurface. Follow U.S. 40 signs
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                   through Roosevelt.

197.9 3.2          U.S. 40 swings east, stay on U.S. 40.

198.5 0.6          Uintah County Line, entering Ballard, Utah. Between Roosevelt and Ft. Duchesne the road
                   travels on alluvium and eolian deposits with some hills of Duchesne River Formation. The
                   Duchesne River Formation has four members. In ascending order, they are the Brennan Basin,
                   Dry Gulch, Lapoint, and Starr Flat members. The Brennan Basin Member crops out on right
                   and the overlying Dry Gulch Member crops out on left. The Lapoint and Starr Flat members
                   crop out to the north. The Starr Flat Member may be equivalent to the Bishop Conglomerate
                   because the units rest on the Gilbert Peak erosion surface, are lithologically similar, and have
                   ash beds with similar radiometric ages between 30 and 32 million years (Hansen, 1986;
                   Bryant and others, 1989; Kowallis and others, this volume).

202.9 4.4          Whiterocks Canyon turnoff, continue east on U.S. 40.

203.6 0.7          Bottle Hollow Resort.

204.7 1.1          Ft. Duchesne turn off, continue east on U.S. 40.

205.1 0.4          Cross Uinta River.

205.8 0.7          Turn left on SR 246 to Lapoint. Marsh Peak is clearly visible straight ahead. Road travels
                   across Duchesne River Formation and alluvium-eo1ian deposits.

210.3 4.5          Little Mountain is ahead; the upper one-third of Little Mountain consists of Bishop
                   Conglomerate.

213.2 2.9          Junction SR121. Turn right on SR 121 to Lapoint. The hills to the north are the Lapoint
                   Member of the Duchesne River Formation.

214.6 1.4          Lapoint.

215.1 0.5          Turn left on Paradise Reservoir Road. Lapoint Member of Duchesne River Formation is
                   exposed in slopes on both sides of road. The Lapoint Member contains several biotite-rich ash
                   beds, which have been dated at 32 to 35 million years (Bryant and others, 1989). Capping the
                   Lapoint Member is alluvial gravel that is correlated with gravel deposits around Vernal. The
                   soil profile has up to stage III calcic-horizon development, which suggest a mid-Pleistocene
                   age.

220.2 5.1          Junction of Tridell road on left. Cross cattle guard and continue toward Paradise
                   Reservoir.

222.0 1.8          Take the left fork of road toward Paradise Reservoir.

223.7 1.7          Cattle guard.

225.1 1.4          Hills are Mancos Shale with cap of Duchesne River Formation.

226.1 1.0          Treaty Line Road. Continue north on Paradise Reservoir road. The Frontier Formation
                   crops out in hills to the right and left.
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226.6 0.5           Road travels off Dakota Sandstone hill and onto valley floor, which is underlain by Morrison
                    and Cedar Mountain Formations. This region, including the valley, contains numerous
                    northwest-southeast-trending faults that repeat and complicate the stratigraphic section. See
                    Haddox and others (this volume) for a detailed description of the faults. The small hill to
                    right has Jurassic Stump, Jurassic Morrison, and Cretaceous Cedar Mountain Formations.
                    The hill to the left and in front is capped by Stump Formation.

227.9 1.3           Triassic-Jurassic Nugget Sandstone crops out on left.

228.2 0.3           The Nugget Sandstone forms southern hogback on the right with underlying Triassic Chinle
                    Formation; the Gartra Member of the Chinle Formation forms the northern hogback.

228.7 0.5           Stream. The valley is formed in the Triassic Moenkopi Formation.

229.4 0.7           Park City Formation and Weber Sandstone forms hogback.

229.5 0.1           Smelter Creek fault. This fault places the Triassic-Jurassic Nugget Sandstone down next to
                    the Pennsylvanian-Permian Weber Sandstone. Slip indicators on the fault surface at this
                    locality show that this fault, like the South Flank fault has experienced two periods of fault
                    movement; it is believed that normal slip was followed later by near strike slip (Haddox and
                    others, this volume). The area contains numerous landslides, most with headwall scarps in
                    the Bishop Conglomerate (see Kowallis and Bradfield in this volume for detailed description
                    of landslides).

229.8 0.3           Chinle Formation crops out in road cut on left.

230.2 0.4           Gartra Member of Chinle Formation is on left.

230.4 0.2           Valley on left (west) side of road is a landslide in the Chinle Formation. The Gartra Member
                    forms the ridges on both sides of the strike valley. A fault along the south side of valley drops
                    the upper Chinle Formation down next to the Moenkopi Formation; thus, the Gartra Member
                    is repeated by faulting.

230.5 0.1           Forest Service boundary.

231.1 0.6           Park City-Phosphoria Formation outcrops along road.

231.6 0.5           Road cuts through landslide deposits.

232.2 0.6           Road crosses near the head of landslide in Triassic Moenkopi Formation.

232.3 0.1           STOP 8 – Hairpin curve on Gartra Member of the Chinle Formation. From this vantage
                    point, some of the northwest-southeast-trending faults are in view. Across the canyon to the
                    east-southeast the Gilbert Peak erosion surface is expressed as a topographic break in slope in
                    which the Oligocene Bishop Conglomerate (dipping about 5 o south) rests unconformably on
                    the Paleozoic and Mesozoic strata (dipping about 25o south). Note that most of these faults
                    do not cut the Gilbert Peak erosion surface; thus, the faults are mostly older than Oligocene.
                    See Haddox and others (this volume) for detailed discussion of these faults. Along the road at
                    the hairpin are good exposures of, first, the Moenkopi Formation, and then, the conglomeratic
                    facies of the Bishop Conglomerate sitting on the Gilbert Peak erosion surface. At the top of
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                   the Bishop Conglomerate is a poorly consolidated to unconsolidated gravel deposit. This
                   gravel is currently mapped as part of the Bishop Conglomerate (Rowley and others, 1985;
                   Sprinkel, 2002), but continued mapping by Sprinkel (2004; final mapping of the Dutch John
                   30’x60’ quadrangle and new mapping on the Kings Peak 30’x60’ quadrangle) may define it as
                   a new map unit. Its age is unknown, but could be as young as early Pleistocene. Across the
                   valley to the east, white outcrops of the sandy, tuffaceous facies of the Bishop Conglomerate
                   peek through up high on the mostly covered slope.

232.4 0.1          Exposures of basal Bishop Conglomerate.

233.3 0.9          Bills Park.

233.4 0.1          Cattle guard. Just beyond the cattle guard on right in low road cut are exposures of white,
                   tuffaceous sands in the Bishop Conglomerate.

235.7 2.3          Loggers Park.

236.1 0.4          Cattle guard.

236.3 0.2          Ice Cave Peak road, turn left.

236.8 0.5          Fork in road, keep right.

237.3 0.5          Fork in road, keep left.

237.9 0.6          STOP 9 – Ice Cave Peak. This stop is on the Mississippian Madison Limestone and provides
                   an excellent view into Whiterocks Canyon (figure 1.7). Across the canyon are exposures of
                   the Madison Limestone and the underlying Neoproterozoic Red Pine Shale. The contact is
                   an angular unconformity that represents nearly 400 million years of missing time. There
                   are several faults that cut and down drop the Madison Limestone. Whiterocks Canyon is a
                   classic U-shaped glaciated canyon with till deposited on the canyon bottom and along much
                   of the canyon margins. Up canyon is a large landslide in failed Red Pine Shale that crossed
                   the canyon and likely formed a temporary landslide dam. Whiterocks River has subsequently
                   cut through the landslide. Return to US Forest Service road to Paradise Park.

239.4 1.5          Intersection of the Ice Cave Peak and Paradise Park roads, turn left and continue up the
                   mountain.

239.9 0.5          Cattle guard.

241.0 1.1          Intersection Paradise Park and Julius Park road; turn right to Julius Park. Follow Julius
                   Park road across earthen dam to parking area near inlet of the Mosby Canal.

241.2 0.2          Cattle guard.

241.3 0.1          STOP 10 – Julius Park; park near inlet of Mosby Canal and hike about ½ mile to the head
                   scarp of the Dry Fork landslide. The road parallels the Mosby Canal; hike to where the road
                   climbs up the steep hill of Smiths Fork till. At the top of the hill, hike off the road and down
                   the till into the forest to the southeast to the headwall of the landslide/debris flow. The Dry
                   Fork landslide failed in pre-glacial (probably younger than the Bishop Conglomerate) alluvial
                   deposits and mobilized into a debris flow that traveled down Dry Fork Canyon to Ashley
                                                                      408
Dehler, Pederson, Sprinkel, and Kowallis, editors                                 2005 Utah Geological Association Publication 33




 Figure 1.7. View south-southwest of the Red Pine Shale of the Uinta Mountain Group and overlying Phanerozoic strata.
 An angular unconformity marks the boundary between the Red Pine Shale and overlying Madison Limestone. This sug-
 gests some uplift prior to deposition of the Madison Limestone. The Lodore Sandstone is not preserved in the Whiterocks
 Canyon and surrounding area (Sprinkel, 2002). East and west of Whiterocks Canyon, the Lodore Sandstone and Tintic
 Quartzite, respectively, unconformably overlies the Red Pine Shale. These basal Cambrian formations vary in thickness
 because of a paleotopography developed on the Red Pine Shale prior to their deposition. This area likely represents a
 large paleohigh in the Red Pine Shale; Yur = Red Pine Shale, Mm = Madison Limestone, Mh = Humbug Formation, Md =
 Doughnut Formation, lPrv = Round Valley Limestone, lPm = Morgan Formation, PlPw = Weber Sandstone, T cm = Chinle
                                                                                                            R
 and Moenkopi Formations, and Qms = landslide deposits.


                     Valley. The landslide failed because the Mosby Canal overtopped its banks and sent a surge
                     of water onto already saturated ground (see detailed discussion of the Dry Fork landslide in
                     Laabs and Carson, this volume). Hike back to the vehicles and drive down the US Forest
                     Service road to the Treaty Line Road.

241.7 0.4           Junction with main Paradise Park road. Turn left.

248.9 7.2           Forest Service boundary, gate, and cattle guard. Continue south on Paradise Park road.

253.3 4.4           Intersection of Treaty Line Road, turn left; Indian land on south and non-Indian land to
                    north. Frontier Formation crops out to the north and parallels road. Head to Dry Fork
                    canyon.

254.7 1.4           Mosby Creek. The cattle guard and bridge here were nearly washed out and the road was
                    closed during high runoff during the spring of 2005.

255.4 0.7           Turn left on route 2728. Continue to Dry Fork Canyon.

255.9 0.5           Cattle loading chute; outcrops of sandstone are channel sands low in the Morrison Formation.
                    The Stump Formation underlies the Morrison Formation and the valley ahead is underlain by
                    Entrada Sandstone.

256.2 0.3           Sharp right turn in road with outcrops of the Carmel Formation on north.

257.1 0.9           Carmel Formation crops out along the road. Above the gray limestone in road cut is a green
                    biotite-rich air-fall ash that has been collected for isotopic dating. This ash is above the first

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Road Guide to the Geology of the Uinta Mountains for the 2005 UGA Field Conference         B,J. Kowallis, D.A. Sprinkel, J.L. Pederson, and C.M.

                   limestone interval, which is likely equivalent to the Co-op Creek Limestone Member of the
                   Carmel Formation elsewhere. Between this mileage and previous mileage, we crossed a fault
                   that put Stump Formation down next to Carmel Formation. The valley is underlain by Entrada
                   Sandstone.

257.2 0.1          Nugget Sandstone contact with the Carmel Formation. The Nugget Sandstone is nicely
                   exposed.

258.6 1.4          Strike valley formed by the upper part of the Chinle Formation.

258.9 0.3          Gartra Member of the Chinle Formation hogback.

259.2 0.3          Cattle guard. Moenkopi Formation strike valley.

259.9 0.7          Park City Formation forms hill with ranch house. The dip slope ahead is Gartra Member of
                   the Chinle Formation that is again faulted down.

260.5 0.6          Pavement ends. Gartra Member of the Chinle Formation on left road cut. To the south there
                   are many small faults that isolate blocks of Gartra Member of the Chinle Formation and
                   Stump Formation. Most faults are down to the north.

262.2 1.7          Switchbacks in road have outcrops of Chinle Formation in road cuts.

262.7 0.5          Cattle guard; the Gartra Member of the Chinle Formation on left and overlying upper Chinle
                   Formation on right. To the right and up the hill is the lower Nugget Sandstone (Bell Springs
                   member; see Jensen and Kowallis in this volume for a description of the Nugget Sandstone).

263.0 0.3          STOP 11 – View of Dry Fork Canyon and Castle Cove fault (figure 1.8). The fault places the
                   Chinle Formation up next to Nugget Sandstone. See Haddox and others (this volume) for
                   detailed description of the Castle Cove and other faults in this region. Discuss faulting and
                   regional stratigraphy of Nugget Sandstone and Bishop Conglomerate.

264.3 1.3          Pavement begins.

268.7 1.4          Intersection of Dry Fork Canyon on
                   left, stay on road to Vernal.

277.1 8.4          Intersection of SR 121, turn left to
                   Vernal.

278.1 1.0          Intersection of 2550 West in Maeser.
                   Continue east on SR 121 to Vernal.

279.2 1.1          Vernal city limit sign.

280.6 1.4          Turn left on Main (U.S. 40). Travel
                   to the Weston Lamplighter.
                                                                            Figure 1.8. View southeast of the Castle Cove fault.
281.3 0.7          Lamplighter Inn.                                         The fault places Nugget Sandstone (JT n) down next to
                                                                                                                R
                                                                            the Moenkopi Formation (T m) and Gartra Member and
                                                                                                      R
                                                                            upper member of the Chinle (T c).
                                                                                                         R
END OF DAY 1
                                                                      410
Dehler, Pederson, Sprinkel, and Kowallis, editors                          2005 Utah Geological Association Publication 33

                                                            Ma maximum age for the lower Uinta Mountain
                         RE FE RE N CE S                    Group [abs.]: Geological Society of America
                                                            Abstracts with Programs.
Bryant, B., 1990, Geologic map of the Salt Lake         Haddox, D.A., Kowallis, B.J., and Shakespeare, J.D.,
    City 30’ x 60’ quadrangle, north-central Utah,          2005, Mapping and kinematic analysis of the
    and Uinta County, Wyoming, with a section on            Deep Creek fault zone, South Flank of the Uinta
    palynologic data from Cretaceous and lower              Mountains, Utah: Utah Geological Association
    Tertiary rocks in the Salt Lake City 30’ x 60’          Guidebook 33 (this volume).
    quadrangle: U.S. Geological Miscellaneous           Hansen, W.R., 1975, The geologic story of the Uinta
    Investigations Series Map I-1944, 2 plates, scale       Mountains, U.S. Geological Survey Bulletin
    1:100,000.                                              1291, 144 p.
— 1992, Geologic and structure maps of the Salt Lake    — 1986, Neogene tectonics and geomorphology of
    City 1˚ x 2˚ quadrangle, Utah and Wyoming: U.S.         the eastern Uinta Mountains in Utah, Colorado,
    Geological Survey Miscellaneous Investigations          and Wyoming: U.S. Geological Survey
    Series Map I-1997, scale 1:250,000.                     Professional Paper 1356, 78 p.
Bryant, B., Naeser, C.W., Marvin, R.F. and Mehnert,     Horodyski, R.J., 1993, Precambrian paleontology
    H.H., 1989, Ages of Late Paleogene and Neogene          of the western conterminous United States and
    tuffs and the beginning of rapid regional               northwest Mexico, in Link and others, editors,
    extension, eastern boundary of the Basin and            Middle and Late Proterozoic stratified rocks of
    Range province near Salt Lake City, Utah, in            the western U.S. Cordillera, Colorado Plateau,
    Evolution of sedimentary basins; Uinta and              and Basin and Range province, Chapter 6, in
    Piceance basins: U.S. Geological Survey Bulletin        Reed, J.C., Bickford, M.E., Houston, R.S., Link,
    1787-K, p. K1-K12                                       P.K., Rankin, D.W., Sims, P.K., and Van Schmus,
Conn, R., 2005, Potential Economic Mineralization           W.R., editors, Precambrian; conterminous U.S.:
    in the Uinta Mountains, Northeastern Utah:              Geological Society of America, The Geology of
    Utah Geological Association Guidebook 33 (this          North America, The Decade of North American
    volume).                                                Geology (DNAG), C-2, p. 558-565.
Crittenden, M.D., Jr., Stuckless, J.S., Kistler, R.W.   Jensen, P.H., and Kowallis, B.J., 2005, Piecing
    and Stern, T.W., 1973, Radiometric dating of            together the Triassic/Jurassic stratigraphy
    intrusive rocks in the Cottonwood area, Utah:           along the South Flank of the Uinta Mountains,
    U.S. Geological Survey Journal of Research, v. 1,       northeast Utah: a preliminary analysis: Utah
    no. 2, p. 173-178.                                      Geological Association Guidebook 33 (this
De Grey, L.D., 2005, Geology of the Swallow Canyon          volume).
    7.5-minute quadrangle, Daggett County, Utah         Kowallis, B.J., Christiansen, E.H., Balls, E., Heizler,
    and Moffat County, Colorado-Facies analysis             M.T., and Sprinkel, D.A., 2005, The Bishop
    and stratigraphy of the Neoproterozoic eastern          Conglomerate Ash Beds, South Flank of the
    Uinta Mountain Group: Pocatello, Idaho State            Uinta Mountains, Utah: Are they pyroclastic fall
    University, M.S. thesis, 122 p.                         beds from the Oligocene ignimbrites of western
Dehler, C.M., Porter, S., De Grey, L.D., and                Utah and eastern Nevada?: Utah Geological
    Sprinkel, D.A., in press, The Neoproterozoic            Association Guidebook 33 (this volume).
    Uinta Mountain Group revisited–a synthesis of       Kowallis, B.J., and Bradfield, T.D., 2005, Landslide
    recent work on the Red Pine Shale and related           hazards along the southern flank of the Uinta
    undivided clastic strata, northeastern Utah, in         Mountains: Utah Geological Association
    Link, P.K., and Lewis, R., editors, Proterozoic         Guidebook 33 (this volume).
    basins of Northwestern U.S.: Society for            Laabs, B., and Carson, E., 2005, Glacial Geology of
    Sedimentary Geology Special Publication.                the Southern Uinta Mountains: Utah Geological
Fanning, M.C., and Dehler, C.M., 2005, Constraining         Association Guidebook 33 (this volume).
    depostional ages for Neoproterozoic siliciclastic   Morgan, C.D., editor, 2000, The Bluebell oil
    sequences through detrital zircon ages–a ca. 770        field, Uinta Basin, Duchesne and Uintah
                                                    411
Road Guide to the Geology of the Uinta Mountains for the 2005 UGA Field Conference   B,J. Kowallis, D.A. Sprinkel, J.L. Pederson, and C.M.

    Counties, Utah: characterization and oil well
    demonstration: Utah Geological Survey Special
    Study 106, 95 p.
Nelson, S.T., Keith, J.D., Constenius, K.N., Olcott, J.,
    Duerichen, E., and Tingey, D.G., 2005, Emerald
    and Fibrous Calcite Mineralization in the
    Southwestern Uinta Mountains: Utah Geological
    Association Guidebook (this volume).
Rowley, P.D., Hansen, W.R., Tweto, O., and Carrara,
    P.E., 1985, Geologic map of the Vernal 1o x 2o
    quadrangle, Colorado, Utah, and Wyoming: U.S.
    Geological Survey Miscellaneous Investigations
    Series Map I-1526, scale 1:250,000.
Sanderson, I.D., 1984, The Mount Watson
    Formation, an interpreted braided-fluvial
    deposit in the Uinta Mountain Group (upper
    Precambrian), Utah: The Mountain Geologist, v.
    21, no. 4, p. 157-164.
Sanderson, I.D., and Wiley, M.T., 1986, The Jesse
    Ewing Canyon Formation, an interpreted fan
    deposit in the basal Uinta Mountain Group
    (Middle Proterozoic), Utah: The Mountain
    Geologist, v. 23, no. 3, p. 77-89.
Smouse, DeForrest, 1993, Altamont-Bluebell, in
    Hill, B.G., and Bereskin, S.R., editors, Oil and
    gas fields of Utah: Utah Geological Association
    Publication 22, unpaginated.
Sprinkel, D.A., 2002, Progress report geologic
    map of the Dutch John 30’ x 60’ quadrangle,
    Utah-Colorado-Wyoming (year 3 of 3): Utah
    Geological Survey Open-File Report 399, scale
    1:62,500.
— 2004, Progress report geological map of the
    Vernal 30’ x 60’ quadrangle, Utah and Colorado
    (year 2 of 3): Utah Geological Survey Open-File
    Report 432, scale 1:100,000.
Utah Division of Oil, Gas, and Mining, 2005,
    Summary production report by field:
    Online,https://fs.ogm.utah.gov/PUB/Oil&Gas/
    Publications/Reports/Production/2005_book/
    BkFd0305.PDF.
Wallace, C.A., 1972, A basin analysis of the upper
    Precambrian Uinta Mountain Group, Utah: Santa
    Barbara, University of California-Santa Barbara,
    Ph.D. dissertation, 412 p.




                                                                      412
Dehler, Pederson, Sprinkel, and Kowallis, editors                                 2005 Utah Geological Association Publication 33

          G E O L OGI C D E S RI PTI O N OF THE EASTERN UINTA MOUNTAINS F R OM
                   V E RN A L TO B RO W NS PARK TO SHEEP C REEK C ANYON

DAY 2 – The second day will cover from Vernal over the Diamond Mountain Plateau into Browns Park
            (figure 2.1). Stops will discuss structural geology, bedrock stratigraphy (highlighting the
            Bishop Conglomerate and Uinta Mountain Group; figures 2.2 and 2.3), and geomorphology.
            From Browns Park, travel up Jesse Ewing Canyon to Clay Basin and to U.S 191. The route
            continues south to Little Hole in Flaming Gorge National Recreation Area, across Flaming
            Gorge Dam, and to Sheep Creek Canyon Geological Area. The last stop is in Sheep Creek
            Canyon. The route continues through Sheep Creek to SR 44, then to Manila and finally to
            Mountain View, Wyoming. Return to Salt Lake via I-80.

0.0       0.0       Leave Lamplighter, Turn right on Main Street and go east to 500 East.

0.3       0.3       Turn left on 500 East and proceed north.

0.8       0.5       Turn right on 500 North and proceed east.

1.9       1.1       Cross Ashley Creek.

3.1       1.2       Landfill on left. The landfill is in the Mancos Shale

3.2       1.3       Turn left at “Y” in the road and proceed to the Brush Creek road.

4.9       1.7       Intersection with paved road to the sewer treatment plant. That road becomes severely damaged
                    from swelling of the Mancos Shale and needs occasional repair work. The road builders did not
                    put down much of a gravel base before the road was asphalted. Stay on road to Brush Creek.
                    The road travels across Mancos Shale and occasional gravel-capped surfaces. The Buckskin Hills
                    are to the north. They are composed of Mancos Shale capped by younger gravels, which makes
                    the reddish color.

7.1       2.2       Take left fork to travel along Brush Creek. The Brush Creek road lies on the Mancos Shale for
                    a distance with the underlying Frontier Formation on the right. In this area, travel is across the
                    western plunging end of the Split Mountain anticline.

9.8       2.7       The road crosses the Mancos/Frontier contact with the upper part of the Frontier Formation
                    exposed to the left of the road.

10.1      0.3       Large concretions typical of the upper part of the Frontier Formation are exposed on left. Note
                    the contact with overlying Mancos Shale (figure 2.4).

10.5      0.4       Cross drainage. The Mowry Shale is in road cut on left.

10.8      0.3       Dakota Sandstone on left.

10.9      0.1       Road is on the Cedar Mountain Formation.

11.0      0.1       Take left fork in road.

11.1      0.1       STOP 1 – Morrison Formation cores one branch of the western end of the Split Mountain

                                                           413
414
                                                                                                                                                                     Road Guide to the Geology of the Uinta Mountains for the 2005 UGA Field Conference




      Figure 2.1. Index map of the Uinta Mountains and surrounding area showing the field conference stops for Day 2. This map provides only a general perspective
      of the stops and a detailed road and/or topographic map to follow road guide directions.
                                                                                                                                                                      B,J. Kowallis, D.A. Sprinkel, J.L. Pederson, and C.M.
Dehler, Pederson, Sprinkel, and Kowallis, editors                                                            2005 Utah Geological Association Publication 33


                                 WESTERN      WEST-CENTRAL    EAST-CENTRAL       EASTERN     RANGE OF KNOWN OCCURENCE
                                                                                              OF FOSSILS AND LOCATION OF
                             UINTA MOUNTAINS UINTA MOUNTAINS UINTA MOUNTAINS UINTA MOUNTAINS     RADIOMETRIC SAMPLE
 Paleozoic



                  M          Deseret Formation                    Madison Limestone
                      360
                  C            Tintic Quartzite                                        Lodore Sandstone
                      543
                  L
                      630
 NEOPROTEROZOIC




                      740
                                            Red Pine Shale




                                                                                                                         770 Ma, U-Pb detrital zircon
                  M




                                                                                                                                                                                                                                                                 Eohyella sp.
                                                                                                                                                                                                                                                                                Bavlinella faveolata
                                                                                                                                                                                                                                                                                                       Chuaria
                  I                           formation of Hades Pass
                  D
                  D                                                                             formation
                  L          Mount Watson                                                          of
                  E           Formation formation of
                                                                                             Crouse Canyon
                                           Dead Horse    formation of Red Castle
                                              Pass




                                                                                                                                                                                                                                 Trachysphaeridium laminaritum
                                                                                                                                                                                                                                         Eossacharomyces sp.
                                                                                             formation of Outlaw Trail

                                                                                                 formation of
                                                                                                                         *
                                formation of
                                                                                               Diamond Breaks
                                                                                                                                                        ?
                               Moosehorn Lake




                                                                                                                                                        v-shaped microfossils
                                                                                                Jesse Ewing
                              undivided unit             ?                   ?




                                                                                                                                                                                algal filament fragments

                                                                                                                                                                                                           Leiosphaeridia spp.
                                                                                              Canyon Formation
                      850
                  E   1000
 MESO-
PROTERO-              1600
  ZOIC
 PROTEROZOIC




                                                                    Red Creek Quartzite(?)   Red Creek Quartzite
   ARCHEAN




                                  Little Willow
    EARLY

     AND




                                   Formation             ?                  and                     and
                                                                    Owiyukuts Complex(?)     Owiyukuts Complex
                      2500

      Figure 2.2. Stratigraphic chart of the Uinta Mountain Group showing tentative correlations of its formations across
 the Uinta Mountains and paleontologic and radiometric data. This chart is based on the continued work by Carol Dehler,
 Doug Sprinkel, Susannah Porter, and Jerry Waanders. Stratigraphic nomenclature is from Wallace (1972), Sanderson
 (1984), Sanderson and Wiley (1986), and De Grey and Dehler (this volume). Paleontology and radiometric data is from
 Horodyski (1993), Fanning and Dehler (2005), Dehler and others (in press), and Sprinkel and Waanders (this volume).
 Distribution of formations based on mapping by Bryant (1992), Sprinkel (2002), and De Grey (2005).


                                 anticline beneath overlying Cedar Mountain and Dakota Sandstone, which are exposed on
                                 limbs. The contact between the Morrison and Cedar Mountain formations is difficult to pick,
                                 but we generally place it at an altered zone (typically yellowish) overlain by a calcrete (figure
                                 2.5). Intersection of Brush Creek and Island Park road, continue on Brush Creek Road to the
                                 north. The road travels through the Dakota Sandstone.

12.2                  1.1        Intersection, take right fork.

12.3                  0.1        Brush Creek Ranch Entrance. Follow road around to left.

13.0                  0.7        Turn right on to Jones Hole road (route 2804). The Buckskin Hills are to the left showing
                                 the Mancos Shale capped by younger gravels of unknown age, but possibly as young as
                                 Pleistocene.

14.2                  1.2        Cross Brush Creek.

                                                                            415
Road Guide to the Geology of the Uinta Mountains for the 2005 UGA Field Conference                      B,J. Kowallis, D.A. Sprinkel, J.L. Pederson, and C.M.



                                       SOUTH FLANK UINTA MOUNTAINS                                    NORTH FLANK UINTA MOUNTAINS
                                         WESTERN        EASTERN                                         WESTERN        EASTERN

            Quaternary                          Glacial and surficial deposits                                 Glacial and surficial deposits
             Pliocene                                Alluvial-gravel deposits                                     Alluvial-gravel deposits
             Miocene                                                                                                                 Browns Park Formation

            Oligocene                                Bishop Conglomerate                                           Bishop Conglomerate
                                                       Duchesne River Formation                                                     Bridger Formation
             Eocene              Keetley Volcanics         Uinta Formation
                                                                                                                                  Green River Formation
                                                        Green River Formation
            Paleocene                                     Wasatch Formation                          Echo Canyon Conglomerate
                                                                                                                                   Wasatch Formation
                                                          Mesaverde Group                           Evanston-Henefer Formations          Mesaverde Group
                                                            Mancos Shale                                    Hilliard Shale                  Baxter Shale
                                                          Frontier Sandstone                             Frontier Sandstone              Frontier Sandstone
                                                                                                            Aspen Shale                     Mowry Shale
            Cretaceous                                       Mowry Shale
                                                          Dakota Sandstone                               Dakota Sandstone                Dakota Sandstone

                                               Cedar Mountain Formation                                Kelvin Formation           Cedar Mountain Formation
                                                  Morrison Formation                                               Morrison Formation
              Jurassic               Preuss Sandstone                    Stump Formation             Preuss Sandstone               Stump Formation
                                      Stump Formation                                                 Stump Formation
                                                                         Carmel Formation                                           Carmel Formation
                                    Twin Creek Limestone                                            Twin Creek Limestone
                                     Nugget Sandstone                    Nugget Sandstone            Nugget Sandstone               Nugget Sandstone

                                  Ankareh Formation                                                Ankareh Formation
              Triassic                                  Chinle Formation                                                 Chinle Formation
                                  Thaynes Limestone                                                Thaynes Limestone
                                                      Moenkopi Formation                                               Moenkopi Formation
                                  Woodside Formation                                               Woodside Formation
             Permian                  Park City-Phosphoria Formation                                   Park City-Phosphoria Formation

                                                  Weber Sandstone                                               Weber Sandstone
          Pennsylvanian                           Morgan Formation                                              Morgan Formation
                                                Round Valley Limestone                                        Round Valley Limestone

                                  Doughnut Formation           Doughnut Formation                                  Doughnut Formation
                                  Humbug Formation
           Mississippian           Deseret Limestone           Humbug Formation                                    Humbug Formation
                                  Gardison Limestone           Madison Limestone                                   Madison Limestone
             Devonian
              Silurain
             Ordovician
                                                                                    Diabase dikes Diabase dikes
             Cambrian                 Tintic Quartzite                    Lodore Sandstone          Tintic Quartzite                 Lodore Sandstone

Figure 2.3. Stratigraphic nomenclature chart of Phanerozoic rocks in the Uinta Mountains and margins of Green River
and Uinta Basins (Rowley, 1985; Bryant, 1992; Sprinkel, 2002).




 Figure 2.4. View west of the upper Frontier Sandstone                                  Figure 2.5. Unconformable contact between the Juras-
 Member of the Mancos Shale that contains large concre-                                 sic Morrison Formation and overlying Cretaceous Cedar
 tions. The upper shale member of the Mancos Shale over-                                Mountain Formation. The unconformity represents about
 lies the Frontier; the contact is placed at the top of the                             25 million years of missing time.
 concretion-laden bed.


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15.5      1.3       STOP 2 – Gravel deposits that cap Donkey Flats. These intermediate-level gravels have stage
                    3 carbonate soil, like that observed below mouth of Whiterocks Canyon, again suggesting a
                    middle Pleistocene age. The Mancos Shale underlies the gravel deposit. Note the phosphate
                    mine to the northwest in the Meade Peak Member of the Phosphoria Formation (Schell and
                    Dyni; 1973). Continue on main road.

19.5      4.0       The Mowry Shale is well exposed.

19.6      0.1       Frontier Formation in road cut.

20.2      0.6       Concretions in the Frontier Formation (figure 2.6)

20.8      0.6       Contact with Mancos Shale.

21.0      0.2       Landslide complex in Mancos Shale.

21.2      0.2       Landslide damage in road.

22.1      0.9       The Bishop Conglomerate is exposed in road cut at hairpin turn.

22.4      0.3       Stop 3 – Spectacular scenic view and road cut in Bishop Conglomerate. The Bishop Conglomerate
                    here is mostly the sandy, tuffaceous facies, with lesser amounts of conglomerate. An ash bed near
                    the top of the road cut was sampled and isotopically dated at 30 million years. See Kowallis and
                    others (this volume) for a detailed description of ash beds in the Bishop Conglomerate. From
                    this locality much of the regional geology can be observed including the Gilbert Peak erosion
                    surface. This is an excellent place to observe and discuss the erosional history of the Uinta
                    Mountains and adjacent Uinta Basin.

26.7      4.3       Take right fork on road at Diamond Creek. The road travels on dissected surface of Bishop
                    Conglomerate with younger, inset alluvium in many places.

30.0      3.3       Turn left on Crouse Canyon road
                    to Browns Park. The road climbs up
                    to Bishop Conglomerate and younger
                    gravels. The southernmost hogbacks
                    are capped by Round Valley Limestone;
                    the northern hogbacks are capped by
                    Madison Limestone with Humbug
                    Formation and Doughnut Formation
                    in between.

32.2      2.2       Take left fork to Crouse Reservoir.
                    The hogback to left is capped by
                    Madison Limestone with Lodore
                    Sandstone underlying. This is also the
                    drainage divide between the Pot Creek
                    drainage to the north and Ashley Valley
                    to the south.
                                                                Figure 2.6. Closer view of the concretions in the Fron-
                                                                tier Sandstone. Note Andy Brehm (Utah State University
33.3      1.1       The Madison Limestone hogback with          geology student) for scale.
                    Lodore Sandstone and Uinta Mountain
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                   Group exposed below.

34.4     1.1       Cattle guard.

35.0     0.6       Intersection of road connecting to the Crouse Canyon road, stay on road that travels north.

35.4     0.4       STOP 4 – Fault scarp along Pot Creek. The fault scarp seen here parallels Pot Creek and is
                   mapped for several miles eastward and westward. The fault is mapped as cutting the Bishop
                   Conglomerate (Hansen and others, 1981; Rowley and others, 1985; Hansen and Rowley, 1991);
                   however, much of the Bishop Conglomerate in this area is covered by younger (Quaternary)
                   gravel deposits. No trench studies have been conducted along this fault scarp so it is uncertain if
                   this fault predates or postdates these younger gravel deposits. This has paleoseismic implications
                   regarding the age of faulting. The fault could be considered an active fault capable of producing
                   a surface-rupturing earthquake if Quaternary deposits are faulted; otherwise, the fault is inactive
                   and the fault scarp has stood since the late Tertiary.

                   West of here a seismic reflection line was shot near the western extent of this fault. The seismic
                   reflection data is moderate quality and suggests a steep north-dipping fault that is down to the
                   north. The surface projection of that fault is on trend with the fault that parallels Pot Creek.
                   The fault cuts the Uinta Mountain Group, which gives the Uinta Mountain Group a greater
                   apparent thickness. Turn around and return to the connecting road to the Crouse Canyon
                   road intersection.

35.8     0.4       Turn left on road connecting to Crouse Canyon road. The road travels east through Uinta
                   Mountain Group and surficial deposits.

37.7     1.9       Intersection of Crouse Canyon road, turn left and travel north.

39.3     0.7       Cattle guard and view of head of Crouse Canyon. The steep and headwardly eroding Crouse
                   Creek is close to capturing upper Pot Creek. Descend down Crouse Canyon. Note the white
                   hills of tuffaceous sandstone of the Bishop Conglomerate. The Uinta Mountain Group forms
                   the reddish outcrops that dip about 12° south.

42.9     3.6       Cattle guard. Bishop Conglomerate forms white outcrops in valley.

43.5     0.6       Junction of Marsh Draw on right, stay on Crouse Canyon road.

44.6     1.1       Junction of Pitt Draw or right, stay on Crouse Canyon road. Road climbs hill of Bishop
                   Conglomerate.

44.8     0.2       This hill of Bishop Conglomerate is about the last exposure to the north that was interpreted by
                   Hansen as deposited in headwater valleys of a south-flowing drainage off the original Eocene-
                   Oligocene drainage divide of the eastern Uintas. View to the south illustrates this broader,
                   relict valley topography. In Miocene time, normal faulting in Browns Park tilted the drainage
                   north, driving the stream capture that is still ongoing. Note steeply incised modern drainage
                   cut through more resistant Uinta Mountain Group immediately to the east. We are about to
                   descend into the more deeply incised part of Crouse Canyon.

46.1     1.3       Crouse Canyon sign. Talus on right composed of Uinta Mountain Group probably formed mostly
                   by Pleistocene periglacial processes. The toe of the talus appears to form a pro-talus rampart.

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47.9      1.8       Mouth of Crouse Canyon. The formation of Outlaw Trail is poorly exposed near the mouth of
                    Crouse Canyon. This informally named formation is a mappable, green shale unit that is ~50-
                    70 m thick and allows the Uinta Mountain Group to be subdivided into 3 units in the eastern
                    Uinta Mountains. This formation can be no older than 770 Ma, based upon a detrital zircon
                    SHRIMP date (Fanning and Dehler, 2005) obtained from a sample of fine-grained sandstone.
                    This formation represents a (marine?) shoreline transgression (Dehler and others, in press).
                    Exposures of Browns Park Formation are in road cuts; travel on alluvial-fan deposits northward
                    with a great view of Browns Park.

48.9      1.0       Junction of Taylor Flat road, turn left. Good exposures of Browns Park Formation capped by
                    Crouse Creek gravel.

50.5      1.6       STOP 5 – Swallow Canyon overlook. View of the superimposed Green River cutting through
                    the Uinta Mountain Group (figure 2.7). Here, the Green River cuts the Uinta Mountain Group,
                    which in part led John Wesley Powell to formulate his ideas of stream development (Powell,
                    1875, 1876). Hansen (1965) discussed the timing and process by which the Green River was
                    integrated through the Uintas into the greater Colorado River drainage is constrained by pre-
                    Green River Browns Park Formation as well as the stratigraphy of inset Green River deposits
                    and terraces visible from this viewpoint. Browns Park is a half graben bounded by the Home
                    Mountain fault on the north flank of the valley. The Home Mountain fault places the Tertiary
                    Browns Park Formation down (on the south) next to the Neoproterozoic Uinta Mountain Group
                    (Hansen, 1965; Sprinkel, 2002). Stone (1993) described the structural geometry of the fault
                    using seismic reflection data.

52.6      2.1       Road intersection, stay on Taylor Flat road.

53.5      0.9       Road crosses pipeline.

53.9      0.4       Road intersection, stay on Taylor Flat
                    road.

54.3      0.4       Intersection, stay on Taylor Flat
                    road.

54.7      0.4       Cattle guard.

54.8      0.1       Intersection, stay left on Taylor
                    Flat road. The road climbs onto an
                                                               Figure 2.7. View west-northwest of the Green River in
                    extensive terrace gravel that dominates
                                                               Swallow Canyon, Browns Park. Browns Park is a large
                    the western Browns Park landscape.         east-trending valley filled with the Browns Park Forma-
                                                               tion, a soft heterogeneous unit of fluvial-lacustrine sand-
55.4      0.6       Cross creek.                               stone, siltstone, and conglomerate. The light-colored for-
                                                               mation covered by terrace gravels in the middle distance
55.7      0.3       Road intersection to Sears Canyon, stay    is the Browns Park Formation. Here, the Green River
                    on Taylor Flat road.                       cuts through a thick section of red quartz sandstone beds
                                                               of the lower Uinta Mountain Group, which is a spur of the
58.5      2.8       Road intersection of Parsons Unit, stay    mountain front along the south side of Browns Park. This
                    on Taylor Flat road.                       and similar places visited by Powell on his historic boat
                                                               trip in 1869 and again in 1871 caused him to ponder why
59.4      0.9       Intersection, stay on Taylor Flat road.    the river choose to cut through the harder Uinta Moun-
                                                               tain Group instead the softer Browns Park Formation.

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Road Guide to the Geology of the Uinta Mountains for the 2005 UGA Field Conference   B,J. Kowallis, D.A. Sprinkel, J.L. Pederson, and C.M.

59.5     0.1       Bridge; cross the Green River.

59.6     0.1       Turn left to John Jarvie Ranch. The Browns Park Formation and overlying Pleistocene gravel
                   deposits are in road cut straight ahead.

59.9     0.3       LUNCH STOP; John Jarvie Ranch, a historic site maintained by the Bureau of Land Management.
                   Discuss the thick and unusual Pleistocene deposit capping the Browns Park Formation of
                   the mesa on the south side of the Green River here. This is interpreted as an outburst-flood
                   deposit from the failure of a mid-Pleistocene landslide dam in lower Red Canyon just upstream.
                   Landsliding in the canyon corresponds to a outer bend of the river cutting into shale beds in
                   the formation of Outlaw Trail. This flood deposit is capped by ‘regular’ Green River gravel and
                   then piedmont gravel from the south. After lunch turn around, turn right to access Jesse Ewing
                   Canyon. Stay on road to Jesse Ewing Canyon road; DO NOT cross the Green River at the bridge
                   past the bridge back.

60.2     0.3       Bridge, stay straight to Jesse Ewing Canyon road.

61.2     1.0       Cattle guard.

61.6     0.4       Turn left on road to Jesse Ewing Canyon on Browns Park road. The Browns Park Formation
                   is well exposed to the right. The road travels up piedmont-gravel deposits.

63.1     1.5       Mountain Home fault. The Brown Park Formation is faulted down next to red shale beds of the
                   lower Uinta Mountain Group. This represents the valley bounding fault that forms the Browns
                   Park half graben.

63.3     0.2       Sign 831; palynology sample location that yielded microfossils (Leiosphaeridia spp. and
                   carbonaceous filaments). This part of the Uinta Mountain Group has been included in the
                   lower part of the Jesse Ewing Canyon Formation (Sanderson and Wiley, 1986); however, this
                   outcrop is within a down-faulted block, and is likely part of the upper part of the Jesse Ewing
                   Canyon Formation or lower part of the overlying unnamed formation of the Uinta Mountain
                   Group (see Sprinkel and Waanders, this volume).

63.6     0.3       STOP 6 – Unnamed fault that places the Neoproterozoic Uinta Mountain Group down on
                   south next to the Archean-Paleoproterozoic Red Creek Quartzite. View the fault and the Jesse
                   Ewing Canyon Formation of the Uinta Mountain Group as defined by Sanderson and Wiley
                   (1986). Also view the Red Creek Quartzite and describe the Owiyukuts Complex, perhaps the
                   oldest rocks in the state of Utah. Jesse Ewing Canyon and the surrounding area have had some
                   mineral exploration for metallic minerals (see Conn, this volume).

64.8     1.2       Jesse Ewing Canyon Formation. This is the basal formation of Uinta Mountain Group and likely
                   represents a combination of alluvial and subaqueous deposition.

65.2     0.4       Cattle guard.

65.7     0.5       Uinta-Sparks fault zone. The Uinta Mountain Group is faulted up against the Baxter Shale;
                   however, the zone is several hundred feet wide here. Road continues into Clay Basin.

66.5     0.8       Intersection of Tri-Corner road. Keep Straight on Browns Park road to Clay Basin.

67.3     0.8       STOP 7 – Clay Basin. Clay Basin gas field was discovered in 1927 by flowing more than 3
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Dehler, Pederson, Sprinkel, and Kowallis, editors                                  2005 Utah Geological Association Publication 33

                     million cubit feet of gas per day from the Cretaceous Frontier Formation (Hummel, 1969).
                     Additional zones in the Dakota Sandstone were also established. Clay Basin gas is an anticlinal
                     trap north of the Uinta fault zone; the anticline is clearly visible in the Mesaverde Group cliffs.
                     Currently, Clay Basin is used as a gas storage unit to help regular gas flow during peak demands
                     in the winter (see Morgan, this volume for detailed discussion).

69.8      2.5       Turn left to Flaming Gorge.

70.8      1.0       Stay left on road to Flaming Gorge.

70.9      0.1       Start pavement and cross Red Creek. The outcrops to the north are Baxter Shale and Mesaverde
                    Group. The rocks to south are Red Creek Quartzite. The Uinta-Sparks fault is to the south.

73.6      2.7       View of Uinta-Sparks fault. The Rock Springs Formation on right is next to upthrown Red Creek
                    Quartzite on left.

74.8      1.2       Road cut in Rock Springs Formation.

76.8      2.0       Goslin Mountain road intersection. The Fort Union Formation is to north with steep cliffs of
                    Wasatch Formation.

78.9      2.1       Utah-Wyoming state line; pavement ends. The hill to south is the dip slope of the Mesaverde
                    Group (Ericson Sandstone).

81.8      2.9       Turn left on U.S. 191 to Dutch John. Drive through road cut of Mesaverde Group. The
                    Mesaverde Group consists of three formations; they are in descending order (traveling south)
                    the Ericson Sandstone, the Rock Springs Formation, and the Blair Sandstone. The Rock Springs
                    Formation contains coal beds and the distinctive white sandstone bed. The basal Blair Sandstone
                    forms the first resistant sandstone unit above the Baxter Shale. The weathering nature of the
                    three formations that comprise the Mesaverde Group forms a lower resistant sandstone of the
                    Blair Sandstone, a strike valley of the lower Rock Springs Formation, and an upper resistant
                    sandstone of the upper Rock Springs Formation and Ericson Sandstone. This is locally known
                    as the Devils Racetrack.

82.4      0.6       Utah-Wyoming state line; road travels across the Baxter Shale.

82.8      0.4       Goslin Mountain road on left.

83.0      0.2       Spring Creek road on right. Cross Antelope Valley, which is floored by Baxter Shale and surficial
                    deposits.

85.4      2.4       Judd Hollow road.

85.5      0.1       Frontier Formation on left with Flaming Gorge National Recreation Area sign on right.

86.4      0.9       Nugget Sandstone, steeply dipping, in road cut. The road swings east and parallels the Uinta-
                    Sparks fault zone.

87.6      1.2       Uinta-Sparks fault zone. The fault places the Neoproterozoic Uinta Mountain Group up against
                    the Triassic Chinle Formation and Triassic-Jurassic Nugget Sandstone.

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88.7     1.1       Intersection of Mustang Ridge Road, stay on U.S. 191 to Dutch John. The Mustang Ridge Fire
                   was in 2002 and was started along U.S. 191 near here by a motorist whose wheel fell off; sparks
                   from the wheel drum caught the grass along the shoulder of the road on fire.

89.2     0.5       Microfossil-bearing olive-green-gray shale beds of the Uinta Mountain Group. These beds are
                   part of the unnamed formation and they contain the microfossil species Eosaccharomyces sp.,
                   Trachysphaeridium laminaritum, Leiosphaeridia spp., and carbonaceous filaments, which
                   indicate a Neoproterozoic in age (see Sprinkel and Waanders, this volume for details).

90.4     1.2       Dutch John, turn left to Little Hole.

91.6     1.2       Road cut of remnant Browns Park Formation-Bishop Conglomerate(?) on left.

93.6     2.0       Intersection of Dripping Springs road, stay on road to Little Hole.

95.8     2.2       Little Hole overlook.

96.1     0.3       Middle Pleistocene sandy fill capped by younger Pleistocene gravels. These finer deposits are
                   thought to be alluvial fill deposited behind an interpreted middle Pleistocene landslide dam
                   downstream.

96.4     0.3       STOP 8 – Little Hole entrance station. Park on lot and hike up paved road back to road cut of
                   sandy fill deposits. Nearby outcrops of piedmont gravels that can be traced to the upper part of
                   this deposit contain the Lava Creek B ash; an ash from the eruption of the Yellowstone caldera
                   at 640 ka. After stop turn around and go back to Dutch John.

102.2 6.0          Turn left on U.S. 191 to Flaming Gorge Dam.

102.6 0.4          Dutch John Draw road.

103.3 0.7          Flaming Gorge Dam overlook. Road travels on the Uinta Mountain Group.

103.9 0.6          Fault in Uinta Mountain Group.

104.6 0.7          River access road below dam on left.

104.9 0.3          Cross Flaming Gorge Dam.

105.7 0.8          Cart Creek Bridge. View of north-dipping Uinta Mountain Group.

105.9 0.2          Road cut in Browns Park Formation.

106.6 0.7          Marina road on right, stay on U.S. 191.

108.5 1.9          Fire Fighter memorial.

109.1 0.6          Flaming Gorge Lodge. The road travels across the Bear Mountain erosion surface of Bradley
                   (1936), which Hansen (1965) later interpreted as the Gilbert Peak surface subsided by the faulting
                   associated with collapse of eastern Uintas and formation of Browns Park in the Miocene.

110.7 1.6          Swett Ranch Historical site.
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111.2 0.5           Junction onto SR 44, turn right.

113.9 2.7           Skull Creek campground.

114.6 0.7           Red Canyon Recreation area. Includes Red Canyon overlook and visitors center. The recreation
                    area and overlook are on the Bear Mountain-Gilbert Peak erosion surface and provides a nice
                    view of Flaming Gorge Reservoir at Red canyon. The Uinta Mountain Group seen here consists
                    of interbedded sandstone and shale beds.

121.5 6.9           Burnt Creek.

122.6 1.1           Deep Creek campground turn off.

123.6 1.0           Fault in Uinta Mountain Group in road cut on right.

124.3 0.7           Carter Creek.

125.1 0.8           Dowd Mountain turn off, stay on SR 44.

125.9 0.8           Sheep Creek Canyon Geological Area Loop. Intersection of Utah Highway 44 and U.S. Forest
                    Service (USFS) road 218.

126.0 0.1           Cattle guard; Neoproterozoic Uinta Mountain Group is exposed on the right. These rocks were
                    deposited by fluvial-deltaic processes. The Uinta Mountain Group is at least 15,000 feet thick,
                    but only 3000 to 4000 feet of Uinta Mountain Group is exposed in the Sheep Creek Canyon
                    area.

126.1 0.1           Road cut in red quartz sandstone of the Uinta Mountain Group. The beds exposed in the
                    road cut strike north 40˚ to 50˚ east and dip about 30˚ northwest. These beds, as well as rocks
                    in the Sheep Creek Canyon Geological Area, form the north flank of the Uinta arch, a broad
                    asymmetrical anticline about 30 miles wide and 160 miles long (Hansen, 1965; Sprinkel, 2003).
                    The Uinta arch actually consists of two large domes that are aligned east-west and separated by a
                    shallow structural saddle, which is crossed by U.S. Highway 191-Utah Highway 44 from Vernal
                    to Manila (Hansen, 1965; Sprinkel, 2003). Thus, the Sheep Creek Canyon Geological Area is on
                    the eastern part of the western dome. Continue west on USFS road 218, which follows along
                    a hill that contains many road cuts that expose the Uinta Mountain Group.

127.7 1.6           Summit Springs. Turnout with USFS information kiosk.

127.9 0.2           Intersection of USFS road 364 and access road to USFS guard station. Stay on the paved road
                    (USFS 218).

128.2 0.3           Cattle guard; Uinta Mountain Group crops out in the area. The poorly vegetated hill to the
                    north (on horizon) is called Windy Ridge. The south-facing slope of Windy Ridge consists of
                    the Mississippian Madison Limestone; however, the Uinta fault zone is above the Spring Creek
                    drainage just below the Madison outcrops.

128.6 0.4           Intersection of USFS 364 road and the access road to Summit Spring Guard Station. Continue
                    west on USFS road 218.

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128.9 0.3          Intersection of Spirit Lake road (USFS 221) and Deep Creek road (USFS 539). Continue west
                   on USFS road 218. The road is still crossing the Uinta Mountain Group.

129.4 0.5          Headwater of Hope Creek, which is spring fed. Road cut in Uinta Mountain Group on left. The
                   beds strike north 50˚ west and dip 62˚ northeast.

129.7 0.3          Intersection of USFS road 93 (Death Valley road). Continue west on USFS road 218.

130.0 0.3          Beginning of switchback. View to the west-northwest of Sheep Creek and Mahogany Draw in
                   the Sheep Creek Canyon Geological Area (Schell, 1969; Sprinkel and others, 2003). The deep
                   red rocks are the quartz sandstone beds of the Uinta Mountain Group. Interbedded with the
                   sandstone beds are green-gray shale beds that contain species of microfossils. These microscopic
                   organisms lived on mud flats and provide a general age for the Uinta Mountain Group of early to
                   middle Neoproterozoic (Sprinkel and others, 2002; see Sprinkel and Waanders, this volume),
                   although new detrital zircon data and correlation suggest the Uinta Mountain Group is mostly
                   (if not entirely) middle Neoproterozoic (Fanning and Dehler, 2005;). The steep hill north of
                   the road is Windy Ridge. Windy Ridge consists of steeply dipping and overturned beds of the
                   Mississippian Madison Limestone. The road is built on the Uinta Mountain Group. The Uinta
                   fault zone is near the base of the Madison Limestone.

132.0 2.0          Cattle guard.

132.4 0.4          STOP 9 - Boundary of Sheep Creek Canyon Geological Area and Palisades Memorial Park
                   overlook (figures 2.8 and 2.9). To the south, Sheep Creek flows down a relatively narrow canyon.
                   Discuss the stratigraphy of the Uinta Mountain Group, the Uinta fault zone, and the 1965 debris
                   flow. A steep cliff of Uinta Mountain Group forms the west bank and cliffs above the river, and
                   the west margin of a large landslide forms the east bank. The Uinta Mountain Group consists of
                   the red quartz sandstone, siltstone, and mudstone beds that form the bowl of the amphitheater.
                   The rim of the amphitheater is formed by the gray cliff of the Mississippian Madison Limestone,
                   which is locally referred to as The Palisades. The southwestern branch of the Uinta fault zone
                   placed the Uinta Mountain Group (on the south) next to the Madison Limestone. West of the
                   Sheep Creek area, the fault likely continues along the base of the Madison cliff to west of Long
                   Park Reservoir. Somewhere west of the reservoir the thrust fault likely cuts down into the Uinta
                   Mountain Group and places the probable middle part of the Uinta Mountain Group over the
                   Red Pine Shale (figure 2.2). The overlook also provides a good view of the debris-flow deposit
                   that destroyed the Palisades campground and killed seven campers (figure 2.10). The debris
                   flow originated about one mile upstream from the campground where east-flowing Sheep Creek
                   makes a turn to the northeast and cuts into a large landslide (figure 2.8).

133.0 0.6          Palisades Memorial Park. Memorial to the seven members of a family who died in a tragic debris
                   flow here on Wednesday, June 9, 1965.

133.4 0.4          Southwest branch of Uinta fault zone and Big Spring. The road and Sheep Creek cut through
                   Windy Ridge just below Palisades Memorial Park. The southwest branch of the Uinta fault
                   placed the red Uinta Mountain Group next to the gray Madison Limestone (figure 2.11). The
                   road continues through Sheep Creek Canyon Geological Area and passes by the steep cliffs of
                   the Madison Limestone. Big Spring can be seen on the left emerging from a large karst feature.
                   Spangler (this volume) describes the Big Spring and the source of its water.

133.5 0.1          View of the northeastern branch of the Uinta fault zone. This branch of the fault zone is
                   complicated and may consist of several small faults. In general, however, the fault zone placed
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 Figure 2.8. Generalized geologic map and schematic cross section of Sheep Creek Canyon Geological Area; modified from
 Hintze and others (2000).

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 Figure 2.9. Stratigraphic column of rock formations and Quaternary deposits within Sheep Creek Canyon Geological
 Area (modified from Hansen, 1965; Schell, 1969). The horizontal red lines in the “Series” and “Lithology” columns rep-
 resent unconformities.

                   the steeply dipping to overturned
                   beds of the Mississippian Humbug
                   and Doughnut Formations over the
                   more gently east-dipping beds of
                   the Pennsylvanian Round Valley and
                   Morgan Formations.

133.6 0.1          West of the road, the Pennsylvanian
                   Round Valley Limestone forms the
                   steep ledges that dip northeast and
                   intersect Sheep Creek.
                                                                            Figure 2.10. Debris-flow deposits (Qmd) at Palisades Me-
                                                                            morial Park as seen from near STOP 1. The debris flow swept
133.8 0.2          A bridge crosses Sheep Creek. The
                                                                            through the Palisade campground on June 9, 1965, destroying the
                   Morgan Formation crops out at stream                     campground and killing seven campers. View is to the southwest.

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Dehler, Pederson, Sprinkel, and Kowallis, editors                                      2005 Utah Geological Association Publication 33

                     level. A small syncline is also preserved
                     west of the road.

134.2 0.4           The lower Weber Sandstone forms the
                    steep cliff along the road.

134.7 0.5           Approximate contact between the
                    lower and upper Weber Sandstone and
                    a good view of Tower Rock. Tower
                    Rock is a hoodoo rock formation in the
                    upper part of the Weber Sandstone.

135.3 0.6           Basal contact of the Permian Grandeur
                    Member of the Park City Formation.
                    The Grandeur Member is mostly
                    sandstone and limestone.                       Figure 2.11. View looking northwest toward the south-
                                                                   western branch of the Uinta fault zone along the loop road
135.4 0.1           Boundary of Sheep Creek Canyon                 (compare with the cross section in figure 2.8); the photo
                    Geological Area (cattle guard). The            was taken less than a mile northeast of Palisades Memorial
                                                                   Park. The red Proterozoic Uinta Mountain Group (Zu) is
                    Park City and Phosphoria formations
                                                                   thrust against the gray Mississippian Madison Limestone
                    crop out at the northeastern boundary          (Mm). The structural relations are difficult to visualize
                    of the geological area.                        in this photograph because of the camera angle, the fault
                                                                   trend, the strike of the rocks, and the less resistant nature
135.8 0.4           Continue      east-northeast       along       of the Uinta Mountain Group as compared to the Madison
                    graveled road. Sheep Creek Canyon              Limestone. The thrust fault (barbed line) is mostly cov-
                    widens to form an alluviated strike            ered by talus and alluvial-fan deposits in this photograph,
                    valley eroded into soft Triassic rocks.        but is near vertical where exposed. Beds of the Uinta
                                                                   Mountain Group steepen northward and are overturned
136.2 0.4           Dowd grave site. Cleophas J. Dowd              along the fault. Beds of the Madison Limestone (Mm)
                    (1857-1898) homesteaded Sheep                  are vertical to overturned. Rock relations preserved in
                    Creek in 1885. C.J. Dowd was killed on         the road cut indicate the fault was reactivated with re-
                    his ranch on April 11, 1898 by Charles         verse movement during the Laramide orogeny between 70
                                                                   and 40 million years ago. Down dropping of the Uinta
                    Reiser, who was either his business
                                                                   Mountains followed a period of crustal stability that be-
                    partner or his hired hand. Dowd’s              gan about 30 to 24 million years ago. Down-to-the-south
                    grave is in Moenkopi Formation and             movement likely continued along the Uinta fault during
                    was apparently not disturbed by the            Miocene time (about 24 to 5 million years ago).
                    debris flow that swept through Sheep
                    Creek Canyon in 1965.

136.8 0.6           Nugget Sandstone forms the cliff on the north side of the road.

137.2 0.4           Bridge over Sheep Creek.

137.3 0.1           View to south of the Park City, Dinwoody, and Moenkopi formations, and the Sheep Creek
                    monocline.

137.7 0.4           Carmel Picnic Area (193 on USFS maps). The rocks south of the picnic area consist of the
                    Moenkopi Formation. The steep cliff north of the picnic area is the Nugget Sandstone.

138.3 0.6           Bridge.

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Road Guide to the Geology of the Uinta Mountains for the 2005 UGA Field Conference   B,J. Kowallis, D.A. Sprinkel, J.L. Pederson, and C.M.

138.4 0.1          Intersection of Sheep Creek Canyon Geological Area loop road (USFS 218) with Utah Highway
                   44. The road cut through the Nugget Sandstone is called Sheep Creek Gap. Northward through
                   the gap, the overlying Carmel Formation and Entrada Sandstone are exposed.

139.0 0.6          Carmel Formation.

140.1 1.1          Leaving Flaming Gorge National Recreation Area.

140.3 0.2          Entrada Sandstone crops out on both sides of SR 44.

140.6 0.3          Stump Formation crop out on both sides of SR 44.

141.4 0.8          Morrison-Cedar Mountain Formation strike valley.

142.1 0.7          Dakota Sandstone road cut.

142.3 0.2          Mowry Shale crops out on both side of SR 44.

142.5 0.2          Frontier Formation forms hogback.

142.7 0.2          Baxter Shale underlies the valley that Manila occupies.

144.5 1.8          Manila city limit.

144.7 0.2          Intersection of SR 43. Turn left on SR 43 to Mountain View, Wyoming. Henrys Fork fault,
                   placed Cretaceous Baxter Shale up against the Tertiary Wasatch Formation (Hansen, 1956;
                   Sprinkel, 2002).

147.9 0.2          Top of Wasatch and base of Green River formations.

152.7 4.8          Utah-Wyoming state line. To the north are the Cathedral Bluffs. They are composed of Bridger
                   Formation.

159.1 6.4          McKinnon, Wyoming.

160.5 1.4          Spirit Lake road on left.

162.7 2.2          Burnt Fork, Wyoming

165.4 2.7          Uinta County line, Wyoming.

171.3 5.9          Lonetree, Wyoming.

172.4 1.1          Henrys Fork creeks.

191.8 19.4         Entering Mountain View, Wyoming. Return to Salt Lake City via I-80 through Evanston,
                   Wyoming.

END OF LOG FOR DAY 2


                                                                      428
Dehler, Pederson, Sprinkel, and Kowallis, editors                        2005 Utah Geological Association Publication 33

                         RE FE RE N CE S                  map of Utah: Utah Geological Survey Map
                                                          179DM, compact disc, scale 1:500,000.
Bradley, W.H., 1936, Geomorphology of the north        Horodyski, R.J., 1993, Precambrian paleontology
   flank of the Uinta Mountains: U.S. Geological           of the western conterminous United States and
   Survey Professional Paper 185-I, p. 163-199.           northwest Mexico, in Link and others, editors,
Bryant, B., 1992, Geologic and structure maps of          Middle and Late Proterozoic stratified rocks of
   the Salt Lake City 1o x 2o quadrangle, Utah and        the western U.S. Cordillera, Colorado Plateau,
   Wyoming: U.S. Geological Survey Miscellaneous          and Basin and Range province, Chapter 6, in
   Investigations Series Map I-1997, scale                Reed, J.C., Bickford, M.E., Houston, R.S., Link,
   1:250,000.                                             P.K., Rankin, D.W., Sims, P.K., and Van Schmus,
De Grey, L.D., 2005, Geology of the Swallow Canyon        W.R., editors, Precambrian; conterminous U.S.:
   7.5-minute quadrangle, Daggett County, Utah            Geological Society of America, The Geology of
   and Moffat County, Colorado-facies analysis            North America, The Decade of North American
   and stratigraphy of the Neoproterozoic eastern         Geology (DNAG), C-2, p. 558-565.
   Uinta Mountain Group: Pocatello, Idaho State        Hummel, J.M., 1969, Anatomy of a gas field
   University, M.S. thesis, 122 p.                        - Clay Basin, Daggett County, Utah, in
Dehler, C.M., Porter, S., De Grey, L.D., and              Lindsay, J.B., editor, Geologic guidebook of
   Sprinkel, D.A., in press, The Neoproterozoic           the Uinta Mountains−Utah's maverick range:
   Uinta Mountain Group revisited–a synthesis of          Intermountain Association of Geologists and
   recent work on the Red Pine Shale and related          Utah Geological Society 16th Annual Field
   undivided clastic strata, northeastern Utah, in        Conference, p. 117-126.
   Link, P.K., and Lewis, R., editors, Proterozoic     Morgan, C., 2005, Clay Basin Gas Field, Daggett
   basins of Northwestern U.S.: Society for               County, Utah, in Dehler, C.M., Pederson, J.L.,
   Sedimentary Geology Special Publication.               Sprinkel, D.A., and Kowallis, B.J., editors, Uinta
Fanning, C.M., and Dehler, C.M., 2005, Constraining       Mountain Geology: Utah Geological Association
   depostional ages for Neoproterozoic siliciclastic      Publication 33 (this volume).
   sequences through detrital zircon ages–a ca. 770    Powell, J.W., 1875, Exploration of the Colorado
   Ma maximum age for the lower Uinta Mountain            River and its tributaries: Washington, D.C.: U.S.
   Group [abs.]: Geological Society of America            Government Printing Office, 291 p.
   Abstracts with Programs.                            – 1876, Report on the geology of the eastern
Hansen, W.R., 1965, Geology of the Flaming Gorge          portion of the Uinta Mountains and a region of
   area Utah-Colorado-Wyoming: U.S. Geological            country adjacent thereto: U.S. Geological and
   Survey Professional Paper 490, 196 p.                  Geographical Survey of the Territories (Powell),
Hansen, W.R., Carrara, P.E., and Rowley, P.D.,            218 p.
   1981, Geologic Map of the Crouse Reservoir          Rowley, P.D., Hansen, W.R., Tweto, O., and Carrara,
   quadrangle, Uintah and Daggett Counties, Utah:         P.E., 1985, Geologic map of the Vernal 1o x 2o
   U.S. Geological Survey Geologic Quadrangle             quadrangle, Colorado, Utah, and Wyoming: U.S.
   Map GQ-1554, scale 1:24,000.                           Geological Survey Miscellaneous Investigations
Hansen, W.R., and Bonilla, M.G., 1956, Geology            Series Map I-1526, scale 1:250,000.
   of the Manila quadrangle, Utah−Wyoming:             Sanderson, I.D., 1984, The Mount Watson
   U.S. Geological Survey Miscellaneous Geologic          Formation, an interpreted braided-fluvial
   Investigations Map I-156, scale 1:24,000.              deposit in the Uinta Mountain Group (upper
Hansen, W.R., and Rowley, P.D., 1991, Geologic            Precambrian), Utah: The Mountain Geologist, v.
   map of the Hoy Mountain quadrangle, Daggett            21, no. 4, p. 157-164.
   and Uintah Counties, Utah, and Moffat County,       Sanderson, I.D., and Wiley, M.T., 1986, The Jesse
   Colorado: U.S. Geological Survey Geologic              Ewing Canyon Formation, an interpreted fan
   Quadrangle Map GQ-1695, scale 1:24,000.                deposit in the basal Uinta Mountain Group
Hintze, L.F., Willis, G.C., Laes, D., Y.M, Sprinkel,      (Middle Proterozoic), Utah: The Mountain
   D.A., and Brown, K.D., 2000, Digital geologic          Geologist, v. 23, no. 3, p. 77-89.
                                                    429
Road Guide to the Geology of the Uinta Mountains for the 2005 UGA Field Conference       B,J. Kowallis, D.A. Sprinkel, J.L. Pederson, and C.M.

Schell, E.M., 1969, Summary of the geology of                                Utah Geological Association Publication 33 (this
    the Sheep Creek Canyon Geological Area and                               volume).
    vicinity, Daggett County, Utah, in Lindsay,                           Stone, D.S., 1993, Tectonic evolution of the Uinta
    J.B., editor, Geologic guidebook of the Uinta                            Mountains - palinspastic restoration of a
    Mountains−Utah’s maverick range: Intermountain                           structural cross section along longitude 109o15’,
    Association of Geologists and Utah Geological                            Utah: Utah Geological Survey Miscellaneous
    Society 16th Annual Field Conference, p. 143-                            Publication 93-8, 19 p.
    152.                                                                  Wallace, C.A., 1972, A basin analysis of the upper
Schell, E.M., and Dyni, J.R., 1973, Preliminary                              Precambrian Uinta Mountain Group, Utah: Santa
    geologic strip maps of the Park City and                                 Barbara, University of California-Santa Barbara,
    Phosphoria Formations, Vernal phosphate area,                            Ph.D. dissertation, 412 p.
    Uintah County, Utah: U.S. Geological Survey
    Open File Report OFR 73-248, scale 1:24,000.
Spangler, L.E., 2005 Geology and karst hydrology
    of the eastern Uinta Mountain – an overview, in
    Dehler, C.M., Pederson, J.L., Sprinkel, D.A., and
    Kowallis, B.J., editors, Uinta Mountain Geology:
    Utah Geological Association Publication 33 (this
    volume).
Sprinkel, D.A., 2002, Progress report geologic
    map of the Dutch John 30’ x 60’ quadrangle,
    Utah-Colorado-Wyoming (year 3 of 3): Utah
    Geological Survey Open-File Report 399, scale
    1:62,500.
– 2003, Geology of Flaming Gorge National
    Recreation Area, Utah-Wyoming, in Sprinkel,
    D.A., Chidsey, T.C., Jr., and Anderson, P.B.,
    editors, Geology of Utah’s Parks and Monuments:
    Utah Geological Association Publication 28
    (second edition), p. 277-299.
Sprinkel, D.A., Waanders, G., and Robbins, E.I.,
    2002, Stratigraphy, palynology, and maturity of
    the Proterozoic Uinta Mountain Group, eastern
    Uinta Mountains, Utah-implications for unit
    thickness [abs.]: Geological Society of America
    Abstracts with Programs, v. 33, no. 4, p. A-18.
Sprinkel, D.A., Park, B., and Stevens, M.D., 2003,
    Geology of Sheep Creek Canyon Geological
    Area, northeastern Utah, in Sprinkel, D.A.,
    Chidsey, T.C., Jr., and Anderson, P.B., editors,
    Geology of Utah’s Parks and Monuments: Utah
    Geological Association Publication 28 (second
    edition), p. 517-528.
Sprinkel, D.A., and Waanders, Gerald, this volume,
    2005, Stratigraphy, organic microfossils, and
    maturation of the Uinta Mountain Group in the
    eastern Uinta Mountains, northeastern Utah, in
    Dehler, C.M., Pederson, J.L., Sprinkel, D.A., and
    Kowallis, B.J., editors, Uinta Mountain Geology:
                                                                      430
Dehler, Pederson, Sprinkel, and Kowallis, editors                           2005 Utah Geological Association Publication 33

              G E O LO GI C D E S CRI P TI ON OF THE MIRROR L AKE SC ENIC BYWAY,
                                   W E S TERN UINTA MOUNTAINS

DAY 3 – Mirror Lake Highway Scenic Byway (figure 3.1). The last leg of the three-day field conference
will travel over the Mirror Lake Highway Scenic Byway to view and discuss the stratigraphy of the Uinta
Mountains Group in the western Uinta Mountains (figure 3.2), Phanerozoic bedrock stratigraphy (figure
3.3), glacial geology, and structural geology.

0.0       0.0       Start at the Department of Natural Resources (DNR) building (1954 W. North Temple,
                    Salt Lake City) at 7:30 am. Leave the DNR building by turning left on North Temple to
                    Redwood Road to access I-80 east. Turn left on Redwood Road to the I-80 eastbound
                    entrance. Travel east on I-80 to I-15 south.

4.7       4.7       Intersection of I-80 and I-15; take I-80 East to Cheyenne and cross Salt Lake Valley on
                    Lake Bonneville deposits and modern alluvium.

10.5      5.8       Cross Wasatch fault onto footwall. The mouth of Parleys Canyon has the Triassic Ankareh
                    Formation on south side of canyon and the Jurassic Nugget Sandstone on the north.
                    The rocks strike north to northeast and dip steeply west. Overlying the Jurassic Nugget
                    Sandstone is the Jurassic Twin Creek Limestone. Much of I-80 from near the mouth of
                    Parleys Canyon to Mountain Dell Reservoir travels across the Twin Creek Limestone.
                    From Mountain Dell Reservoir to Lambs Canyon, I-80 travels across basal part of the
                    Preuss Sandstone covered by surficial deposits. Numerous landslides are obvious along
                    the interstate.

21.8      11.3      Parleys Summit in Preuss Sandstone.

26.5      4.7       Kimball Junction Exit. Note ski jumps on right (south) from the 2002 Winter Olympics.
                    The ski jumps are cut into a hill of Mesozoic strata.

29.4      2.9       Take U.S. 40 south to Heber City and Vernal.

33.1      3.7       Take exit 2 to Park City and Kamas.

33.4      0.3       Turn left at the bottom of the exit and travel east on SR 248. Road cuts along SR
                    248 are in Keetley Volcanics. The Keetley Volcanics is a heterogeneous mix of lahar, flow
                    breccia and tuff with an age range of 36.0 +/- 3.8 to 32.7 +/- 1.0 m.y. (Crittenden and
                    others, 1973; Bryant and others, 1989; Bryant, 1990). Bryant and others (1989) indicate
                    that “intrusions presumed to be feeders for the Keetley volcanic field are aligned along
                    and west of the trend of the Uinta Mountains,” suggesting that the structures controlling
                    formation of the mountains also helped localize the volcanic and intrusive activity.

40.0      6.6       Summit County line.

43.1      3.1       Turn right on Spring Meadow Way.

43.4      0.3       Turn left on 200 south and proceed east.

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      Figure 3.1. Index map of the Uinta Mountains and surrounding area showing the field conference stops for Day 3. This map provides only a general perspective
      of the stops and a detailed road and/or topographic map to follow road guide directions.
                                                                                                                                                                      B,J. Kowallis, D.A. Sprinkel, J.L. Pederson, and C.M.
Dehler, Pederson, Sprinkel, and Kowallis, editors                                                            2005 Utah Geological Association Publication 33


                                 WESTERN      WEST-CENTRAL    EAST-CENTRAL       EASTERN     RANGE OF KNOWN OCCURENCE
                                                                                              OF FOSSILS AND LOCATION OF
                             UINTA MOUNTAINS UINTA MOUNTAINS UINTA MOUNTAINS UINTA MOUNTAINS     RADIOMETRIC SAMPLE
 Paleozoic



                  M          Deseret Formation                   Madison Limestone
                      360
                  C            Tintic Quartzite                                        Lodore Sandstone
                      543
                  L
                      630
 NEOPROTEROZOIC




                      740
                                            Red Pine Shale




                                                                                                                         770 Ma, U-Pb detrital zircon
                  M




                                                                                                                                                                                                                                                                 Eohyella sp.
                                                                                                                                                                                                                                                                                Bavlinella faveolata
                                                                                                                                                                                                                                                                                                       Chuaria
                  I                           formation of Hades Pass
                  D
                  D                                                                             formation
                  L          Mount Watson                                                          of
                  E           Formation formation of
                                                                                             Crouse Canyon
                                           Dead Horse    formation of Red Castle
                                              Pass




                                                                                                                                                                                                                                 Trachysphaeridium laminaritum
                                                                                                                                                                                                                                         Eossacharomyces sp.
                                                                                             formation of Outlaw Trail

                                                                                                 formation of
                                                                                                                         *
                                formation of
                                                                                               Diamond Breaks
                                                                                                                                                        ?
                               Moosehorn Lake




                                                                                                                                                        v-shaped microfossils
                                                                                                Jesse Ewing
                              undivided unit             ?                   ?




                                                                                                                                                                                algal filament fragments

                                                                                                                                                                                                           Leiosphaeridia spp.
                                                                                              Canyon Formation
                      850
                  E   1000
 MESO-
PROTERO-              1600
  ZOIC
 PROTEROZOIC




                                                                    Red Creek Quartzite(?)   Red Creek Quartzite
   ARCHEAN




                                  Little Willow
    EARLY

     AND




                                   Formation             ?                  and                     and
                                                                    Owiyukuts Complex(?)     Owiyukuts Complex
                      2500

 Figure 3.2. Stratigraphic chart of the Uinta Mountain Group showing tentative correlations of its formations across the
 Uinta Mountains and paleontologic and radiometric data. This chart is based on the continued work by Carol Dehler,
 Doug Sprinkel, Susannah Porter, and Jerry Waanders. Stratigraphic nomenclature is from Wallace (1972), Sanderson
 (1984), Sanderson and Wiley (1986), and De Grey and Dehler (this volume). Paleontology and radiometric data is from
 Horodyski (1993), Fanning and Dehler (2005), Dehler and others (in press), and Sprinkel and Waanders (this volume).
 Distribution of formations based on mapping by Bryant (1992), Sprinkel (2002), and De Grey (2005).


43.5                  0.1       STOP 1 - View of Kamas Valley. Discuss nose of Uinta Mountains and drainage divide
                                along with the history of the Weber and Provo rivers and general geology. Also discuss
                                structure from Precambrian through Paleozoic time, the Tooele arch, and mineralization
                                of Park City and Bingham mining districts.

44.2                  0.7       Turn right onto SR 248 we travel east to Kamas.

45.2                  1.0       Intersection of SR 248 and SR 32. Turn right on SR 32.

45.4                  0.2       Turn right on SR 150 to Mirror Lake. Road travels up Beaver Creek, which contains
                                modern alluvium and some Holocene to Pleistocene alluvial-fan deposits.

47.6                  2.2       The outcrops on slope to north are mapped as Weber Sandstone and mapped on south as
                                Round Valley Limestone; however, the exposures in road cut on north look like Humbug
                                Formation with Round Valley Limestone and Morgan Formation outcrops on south.
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                                       SOUTH FLANK UINTA MOUNTAINS                                    NORTH FLANK UINTA MOUNTAINS
                                         WESTERN        EASTERN                                         WESTERN        EASTERN

            Quaternary                          Glacial and surficial deposits                                 Glacial and surficial deposits
             Pliocene                                Alluvial-gravel deposits                                     Alluvial-gravel deposits
             Miocene                                                                                                                 Browns Park Formation

            Oligocene                                Bishop Conglomerate                                           Bishop Conglomerate
                                                       Duchesne River Formation                                                     Bridger Formation
             Eocene              Keetley Volcanics         Uinta Formation
                                                                                                                                  Green River Formation
                                                        Green River Formation
            Paleocene                                     Wasatch Formation                          Echo Canyon Conglomerate
                                                                                                                                   Wasatch Formation
                                                          Mesaverde Group                           Evanston-Henefer Formations          Mesaverde Group
                                                            Mancos Shale                                    Hilliard Shale                  Baxter Shale
                                                          Frontier Sandstone                             Frontier Sandstone              Frontier Sandstone
                                                                                                            Aspen Shale                     Mowry Shale
            Cretaceous                                       Mowry Shale
                                                          Dakota Sandstone                               Dakota Sandstone                Dakota Sandstone

                                               Cedar Mountain Formation                                Kelvin Formation           Cedar Mountain Formation
                                                  Morrison Formation                                               Morrison Formation
             Jurassic                Preuss Sandstone                     Stump Formation            Preuss Sandstone               Stump Formation
                                      Stump Formation                                                 Stump Formation
                                    Twin Creek Limestone                  Carmel Formation          Twin Creek Limestone            Carmel Formation
                                     Nugget Sandstone                     Nugget Sandstone           Nugget Sandstone               Nugget Sandstone

                                  Ankareh Formation                                                Ankareh Formation
              Triassic                                  Chinle Formation                                                 Chinle Formation
                                  Thaynes Limestone                                                Thaynes Limestone
                                                      Moenkopi Formation                                               Moenkopi Formation
                                  Woodside Formation                                               Woodside Formation
             Permian                  Park City-Phosphoria Formation                                   Park City-Phosphoria Formation

                                                  Weber Sandstone                                               Weber Sandstone
          Pennsylvanian                           Morgan Formation                                              Morgan Formation
                                                Round Valley Limestone                                        Round Valley Limestone

                                  Doughnut Formation           Doughnut Formation                                  Doughnut Formation
                                  Humbug Formation
          Mississippian            Deseret Limestone           Humbug Formation                                    Humbug Formation
                                  Gardison Limestone           Madison Limestone                                   Madison Limestone
             Devonian
              Silurain
             Ordovician
                                                                                    Diabase dikes Diabase dikes
             Cambrian                 Tintic Quartzite                    Lodore Sandstone          Tintic Quartzite                 Lodore Sandstone

 Figure 3.3. Stratigraphic nomenclature chart of Phanerozoic rocks in the Uinta Mountains and margins of Green River
 and Uinta Basins (Rowley, 1985; Bryant, 1992; Sprinkel, 2002).



48.6     1.0       Kamas Fish Hatchery; road cut on left is mapped as Mississippian limestone. These
                   outcrops likely represent the Deseret Formation.

49.2     0.6       Beaver Creek Nudist Ranch (visitors welcomed).

49.5     0.3       Road cut on left (north) is Gardison Limestone to lower Deseret Formation; mapped as
                   Madison Limestone by Bryant (1990, 1992). It contains abundant crinoidal fossil hash
                   and oolites. Some beds may contain dark phosphatic shale of the Delle Member of the
                   Deseret Formation.

49.8     0.3       Fitchville Formation.

50.9     1.1       The Neoproterozoic Red Pine Shale of the Uinta Mountain Group is exposed along creek
                   on right. Road cut contains small landslide of Red Pine Shale.

51.5     0.6       Wasatch National Forest boundary.

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52.0      0.5       Yellow Pine Creek.

52.1      0.1       Yellow Pine Campground. The deposits near campground include outwash and till of
                    Blacks Fork(?) age. Some Smiths Fork till is preserved along Yellow Pine Creek.

52.5      0.4       Glacial till or outwash exposed on left.

53.8      1.3       Beaver Creek Picnic Area.

54.2      0.4       Coop Creek

54.5      0.3       Taylors Fork Campground.

54.9      0.4       Shingle Creek Campground on right. Across from campground is road cut of Red Pine
                    Shale. The road travels along older till (Blacks Fork?) from between Coop Creek and
                    Shingle Creek.

55.4      0.5       Drainage divide between Weber and Provo rivers in glacial till.

56.1      0.7       Pine Valley Group campground turn off, Stay on SR 150.

56.9      0.8       STOP 2 – Stream capture of Beaver Creek by Provo River. Describe the sequence and
                    timing of capture at Pine Valley (Hansen, 1975). Describe regional geology. The broad
                    slope we are standing on is mapped as glacial outwash of pre-Smiths Fork age by Bryant
                    (1992).

57.1      0.2       Cross North Fork of Provo River. Crossing into Smiths Fork till on the east side of North
                    Fork of Provo River.

57.2      0.1       North Fork trailhead.

59.4      2.2       The formation of Hades Pass crops out on slope on either side of SR 150. This formation
                    forms ledgy cliffs with slopes of periglacial talus and colluvium of Pleistocene age.

59.8      0.4       Rock Creek.

60.1      0.3       Junction of Soapstone Basin road, stay on SR 150.

61.2      1.1       Soapstone Campground, road travels on Smiths Fork till with formation of Hades Pass
                    forming high cliffs on both sides of road.

62.2      1.0       Shady Dell Campground on right.

62.9      0.7       Spring Canyon Creek.

63.3      0.4       Duchesne Tunnel campground on right and Alexander Lake road a few tens of feet on

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Road Guide to the Geology of the Uinta Mountains for the 2005 UGA Field Conference           B,J. Kowallis, D.A. Sprinkel, J.L. Pederson, and C.M.

                   left.

63.7     0.4       Formation of Hades Pass exposed in cliffs on the left.

64.5     0.8       Cobblerest Campground on right.

67.0     2.5       STOP 3 – Hoyt Canyon fault. The Murdock Basin road intersection is on the right.
                   Good view of Bald Mountain (11,943) to north. The light-colored quartzite and quartz
                   sandstone of the Mount Watson Formation is exposed on west and the formation of
                   Moosehorn Lake is not well
                   exposed to the east. Southward,
                   the formation of Hades Pass forms
                   the cliffs. The Hoyt Canyon normal
                   fault is poorly exposed near here
                   where the formation of Hades Pass
                   is faulted down (to the south) next
                   to the formation of Moosehorn
                   Lake and Mount Watson Formation
                   (Bryant, 1992).

68.0     1.0       STOP 4 – Slate Gorge overlook
                   (figure 3.4). View the formation
                   of Moosehorn Lake, which is the
                   oldest exposed unit in the Uinta
                   Mountain Group in the western
                   Uinta Mountains (figure 3.2).                            Figure 3.4. View north-northeast of Slate Gorge. The
                                                                            Provo River cuts through the Mount Watson Formation and
68.8     0.8       Cross Provo River.                                       exposes the underlying formation of Moosehorn Lake.

69.4     0.6       Provo River Falls viewpoint
                   (figure 3.5). Provo River cascades
                   over the quartz sandstone and
                   orthoquartzite beds of the Mount
                   Watson Formation.

71.0     1.6       Trial Lake road intersection on left,
                   stay on SR 150. Mount Watson
                   Formation is exposed in road cut.
                   Much of the till is restricted to thin
                   ground till and most road cuts are
                   bedrock.

72.1     1.1       Lily Lake.     Interbedded shale
                   and siltstone of the formation of
                   Moosehorn Lake.
                                                                            Figure 3.5. View north-northwest of Provo River Falls. The
74.8     2.7       STOP 5 – Bald Mountain Pass and                          Provo Rivers cascades over light-colored quartz sandstone
                                                                            and orthoquartzite beds of the Mount Watson Formation.

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Dehler, Pederson, Sprinkel, and Kowallis, editors                              2005 Utah Geological Association Publication 33

                     turn off for Bald Mountain Picnic area. Turn left into Bald Mountain Picnic area for
                     view the Mount Watson Formation. Turn left on SR 150 to Mirror Lake.

74.9      0.1       Duchesne County line. Outcrop of quartz sandstone lithofacies of Mount Watson
                    Formation.

75.1      0.2       Fine-grained lithofacies of the formation of Moosehorn Lake.

75.6      0.5       STOP 6 – Mirror Lake overlook. A nice view of Hayden Peak (12,479 feet) is to the
                    northeast in which the formation of Hades Pass forms the reddish cap (figure 3.6). The
                    lighter-colored Mount Watson Formation underlies the formation of Hades Pass. Hayden
                    Peak is faulted on the north and south. The rocks that form Hayden Peak are dipping
                    northward. The axis of the Uinta
                    arch is mapped approximately
                    through here by Bryant (1992). The
                    formation of Moosehorn Lake crops
                    out along the highway and across
                    from the parking lot. A walk across
                    the street shows polished surface on
                    sandstone beds within the formation
                    of Moosehorn Lake. Possible soft-
                    sediment deformation features are
                    also exposed in the sandstone beds.
                    This stop provides a nice overview
                    of the regional bedrock stratigraphy
                    and the glacial history of Mirror
                    Lake Area. Significant thickness of
                    Smiths Fork-age ice covered all but
                    mountain tops, in contrast to the
                    smaller glacial extent in the eastern
                    Uintas.

76.2      0.6       Moosehorn Campground is on left
                    and great view of Bald Mountain
                    and the Mount Watson Formation.

76.9      0.7       LUNCH STOP – Mirror Lake turn
                    off on right. Stop for lunch.

77.1      0.2       Quartz sandstone beds of the Mount
                    Watson outcrops on the left.            Figure 3.6. View northeast of Hayden Peak (12,479
                                                            feet). The formation of Hades Pass (Yuh; reddish unit)
77.5      0.4       Pass Lake. View of the formation        caps the peak with most of the mountain comprised of
                    of Hades Pass in cliffs on peaks to     the underlying lighter-colored Mount Watson Formation.
                    north.                                  (Yuw) Hayden Peak is faulted on the north and south. The
                                                            rocks that form Hayden Peak are dipping northward. The
                                                            axis of the Uinta arch is mapped by Bryant (1992) ap-
78.9      1.4       Camp Steiner Boy Scout Camp             proximately through the Hayden Peak overlook stop.

                                                      437
Road Guide to the Geology of the Uinta Mountains for the 2005 UGA Field Conference   B,J. Kowallis, D.A. Sprinkel, J.L. Pederson, and C.M.

                   entrance on left.

79.2     0.3       Fine-grained interbeds in the upper part of the Mount Watson Formation.

79.5     0.3       Mount Watson Formation; feldspathic quartzite to sandstone beds with good cross
                   stratification.

79.7     0.2       Butterfly Lake.

79.8     0.1       Summit County line and trailhead for Highline Trail. Road descends into glaciated valley
                   of the Hayden Fork. Glacial deposits are Smiths Fork till (Munroe, 2001).

80.6     0.8       Ruth Lake intersection on left.

81.9     1.3       Glacial till of Smiths Fork age (Munroe, 2001) is along road dominated by purple-
                   red cobbles and boulders (formation of Hades Pass). The till blankets Mount Watson
                   Formation.

82.5     0.6       STOP 7 – Kletting Peak turnout. Walk back uphill one-tenth mile to road cut to view
                   sedimentology and deformation of the fine-grained interbeds in the Mt. Watson Formation.
                   Small-scale thrust faults are preserved in outcrops along with soft-sediment deformation
                   and channeled sandstones (figure 3.7). Also, glacial till of Smiths Fork age (Munroe,
                   2001) caps the bedrock.

82.8     0.3       Formation of Hades Pass is exposed in road cut on left.

84.6     1.8       Sulfur Campground on right; road travels mostly on till. Hayden Fork of Bear River on
                   right.

87.5     2.9       Beaver View Campground on right.

88.1     0.6       Hayden Fork Campground.

89.0     0.9       Gold Hill turn off on left.

89.3     0.3       Moraine of Smiths Fork age on right (east).

91.2     1.9       Bear River.

91.3     0.1       Stillwater Campground on right.

91.6     0.3       Christmas Meadows turn off on right.

92.1     0.5       Bear River Ranger Station. A moraine of probable Smiths Fork age is near here (Munroe,
                   2001). The glacial till north of the Bear River Ranger Station is of Blacks Fork age
                   (Munroe, 2001).


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Dehler, Pederson, Sprinkel, and Kowallis, editors                                2005 Utah Geological Association Publication 33

93.2      1.1       Lilly Lake turn off on right.

93.9      0.7       Bear River Campground on left.

94.0      0.1       East Fork of Bear River.

94.3      0.3       Intersection of North Slope road.
                    The road travels across Smiths Fork
                    till.

95.3      1.0       STOP 8 – Parking lot at intersection
                    of USFS 058 on east side of road just
                    south of Forest Service boundary.
                    Note the unusually large and rugged
                    end moraine complex visible from
                    this point. Called the ‘Manor Lands
                                                          Figure 3.7. Internal deformation within the Uinta Moun-
                    moraine’ by early workers, there
                                                          tain Group is likely more common than generally consid-
                    has been some disagreement over ered, which may account for some of its great thickness.
                    whether this is a Blacks Fork-age     Here, a small thrust fault cuts bedding within a shale unit
                    moraine with unusually rugged near the top of the Mount Watson Formation.
                    topography, or a Smiths Fork
                    moraine that is anomalous in having
                    extended beyond the Blacks Fork moraine (there are no preserved moraines downstream).
                    Newer studies and associated geochronology will help to resolve this.

96.9      1.6       The road crosses the approximate position of the North Flank fault.

99.3      2.4       Hill on right is probably outwash gravel or possibly Blacks Fork till.

100.3 1.0           Utah-Wyoming state line. Road travels across broad outwash plain.

104.1 3.8           Hills to north are steeply dipping Cretaceous Frontier Formation underlain by Hilliard
                    Shale.

112.2 8.1           Junction of Uinta County roads 173 ad 146.

113.2 1.0           Hills on right are steeply north-dipping beds of Ft. Union and Wasatch formations.

114.5 1.3           Junction of Uinta County road 157.

116.3 1.8           Rocks to right are flat-lying beds of post-Sevier age. These beds likely overlie
                    (unconformably) the steep-dipping beds of Cretaceous age.

121.1 4.8           Evanston city limits.

END of LOG


                                                          439
Road Guide to the Geology of the Uinta Mountains for the 2005 UGA Field Conference       B,J. Kowallis, D.A. Sprinkel, J.L. Pederson, and C.M.

                       RE FE RE N CE S                                       Uinta Mountains, U.S. Geological Survey
                                                                             Bulletin 1291, 144 p.
Bryant, Bruce, 1990, Geologic map of the Salt Lake                        Horodyski, R.J., 1993, Precambrian paleontology
    City 30’ x 60’ quadrangle, north-central Utah,                           of the western conterminous United States and
    and Uinta County, Wyoming, with a section on                             northwest Mexico, in Link and others, editors,
    palynologic data from Cretaceous and lower                               Middle and Late Proterozoic stratified rocks of
    Tertiary rocks in the Salt Lake City 30’ x 60’                           the western U.S. Cordillera, Colorado Plateau,
    quadrangle: U.S. Geological Miscellaneous                                and Basin and Range province, Chapter 6, in
    Investigations Series Map I-1944, 2 plates,                              Reed, J.C., Bickford, M.E., Houston, R.S., Link,
    scale 1:100,000.                                                         P.K., Rankin, D.W., Sims, P.K., and Van Schmus,
– 1992, Geologic and structure maps of the Salt Lake                         W.R., editors, Precambrian; conterminous U.S.:
    City 1o x 2 o quadrangle, Utah and Wyoming:                              Geological Society of America, The Geology of
    U.S.    Geological     Survey     Miscellaneous                          North America, The Decade of North American
    Investigations Series Map I-1997, 2 plates,                              Geology (DNAG), C-2, p. 558-565.
    scale 1:250,000.                                                      Munroe, J.S., 2001, Late Quaternary history of the
Bryant, Bruce, Naeser, C.W., Marvin, R.F. and                                northern Uinta Mountains, northeastern Utah:
    Mehnert, H.H., 1989, Ages of Late Paleogene                              Madison, University of Wisconsin-Madison,
    and Neogene tuffs and the beginning of rapid                             Ph.D. dissertation, 398 p.
    regional extension, eastern boundary of the                           Sanderson, I.D., 1984, The Mount Watson
    Basin and Range province near Salt Lake City,                            Formation, an interpreted braided-fluvial
    Utah, in Evolution of sedimentary basins;                                deposit in the Uinta Mountain Group (upper
    Uinta and Piceance basins: U.S. Geological                               Precambrian), Utah: The Mountain Geologist,
    Survey Bulletin, 1787-K, p. K1-K12                                       v. 21, no. 4, p. 157-164.
Crittenden, M.D., Jr., Stuckless, J.S., Kistler, R.W.                     Sanderson, I.D., and Wiley, M.T., 1986, The Jesse
    and Stern, T.W., 1973, Radiometric dating of                             Ewing Canyon Formation, an interpreted fan
    intrusive rocks in the Cottonwood area, Utah:                            deposit in the basal Uinta Mountain Group
    U.S. Geological Survey Journal of Research, v.                           (Middle Proterozoic), Utah: The Mountain
    1, no. 2, p. 173-178.                                                    Geologist, v. 23, no. 3, p. 77-89.
De Grey, L.D., 2005, Geology of the Swallow Canyon                        Sprinkel, D.A., 2002, Progress report geologic
    7.5-minute quadrangle, Daggett County, Utah                              map of the Dutch John 30’ x 60’ quadrangle,
    and Moffat County, Colorado-Facies analysis                              Utah-Colorado-Wyoming (year 3 of 3): Utah
    and stratigraphy of the Neoproterozoic eastern                           Geological Survey Open-File Report 399, scale
    Uinta Mountain Group: Pocatello, Idaho State                             1:62,500.
    University, M.S. thesis, 122 p.                                       Wallace, C.A., 1972, A basin analysis of the upper
Dehler, C.M., Porter, S., De Grey, L.D., and                                 Precambrian Uinta Mountain Group, Utah:
    Sprinkel, D.A., in press, The Neoproterozoic                             Santa Barbara, University of California-Santa
    Uinta Mountain Group revisited–a synthesis of                            Barbara, Ph.D. dissertation, 412 p.
    recent work on the Red Pine Shale and related
    undivided clastic strata, northeastern Utah, in
    Link, P.K., and Lewis, R., editors, Proterozoic
    basins of Northwestern U.S.: Society for
    Sedimentary Geology Special Publication.
Fanning, C.M., and Dehler, C.M., 2005, Constraining
    depostional ages for Neoproterozoic siliciclastic
    sequences through detrital zircon ages: A ca.
    770 Ma maximum age for the lower Uinta
    Mountain Group [abs.]: Geological Society of
    America Abstracts with Programs.
Hansen, W.R., 1975, The geologic story of the
                                                                      440
Dehler, Pederson, Sprinkel, and Kowallis, editors                              2005 Utah Geological Association Publication 33

      G E O LO G I C D E S CRI P TI O N OF AL ONG THE NORTH SL OPE ROAD F ROM T H E
             MI RROR LA K E S CE NI C BYWAY TO MOUNTAIN VIEW, WYOMING

D AY 3 – The afternoon segment of day 3 travels on the U.S. Forest Service (USFS) road 058, also known
as the North Slope road, from near the Bear River Ranger Station on SR 150 to Mountain View, Wyoming
(figure 3.1). This segment of the trip travels along the north flank of the Uinta Mountains where excellent
examples of glacial geology are preserved in Bear River, Blacks Forks, and Smiths Fork drainages (Munroe,
2001). Bedrock units are the same as what we have seen in previous days (figures 3.2 and 3.3). This route
is north of, and generally parallel to, exposures of the North Flank fault zone (Bryant, 1992). This fault
zone is part of the fault system on the north side of the Uinta Mountains on which the range was uplifted
during the Laramide orogeny (Hansen, 1975; Bradley, 1995). We will also cross a segment of the Bear
River fault zone that has well-developed fault scarps in Quaternary deposits (West, 1993, 1994). The road
is generally graveled and can be traveled without the 4-wheel drive vehicles; however, the section from
Blacks Fork to the Hewinta Guard Station is rough and requires high-clearance vehicles. In places along
this section, 4-wheel drive vehicles may be needed if the road is wet.

MI L E A G E D E S CRI P TI O N
(CUMULATIVE/ INCREMENT)

0.0       0.0       Junction of SR 150 and USFS road 058 (North Slope road). Turn right on USFS road 058
                    and travel east. The road travels across Smiths Fork till.

1.6       1.6       STOP 1 – Bear River fault. Junction of USFS road 059 to Boy Scout Camp on right. West
                    (1992, 1993) mapped faults scarps of the Bear River fault in Blacks Fork till near this
                    intersection. The Bear River fault zone is a series of right-stepping en echelon normal faults
                    that have down-to-the-west displacement in Pleistocene and Holocene deposits (West 1993,
                    1994). Fault scarp heights range from 1.5 to more than 49 feet. Trench studies by West
                    (1994) indicate that two surface-rupturing events can be documented; the mean age of
                    the penultimate event is 4620 years before present (yr. B.P.) and the mean age of the most
                    recent event is 2370 yr. B.P. Stay on USFS road 058, North Slope road.

                    You may take a side trip, 1.8 miles south on the Boy Scout Camp road, to view a fault scarp
                    on part of the Bear River fault zone. This fault scarp, called the Big Burn scarp, was one of
                    several trenches excavated by West (1994) to evaluate the seismogenic potential of the Bear
                    River fault zone. From the Big Burn scarp trench, West (1994) reported a single event based
                    on data collected; however, the scarp height (about 40 feet) suggested multiple surface-
                    faulting events likely occurred at this site. Net vertical displacement cause by the single
                    event ranged from 12.8 to 20.7 feet and radiocarbon dating of a buried soil interpreted to
                    have formed on the scarp prior to the last rupture event indicates the latest movement on
                    this segment of the fault was between 3400 to 2600 yr B.P. (West, 1994). Trenches were
                    also cut on other nearby scarps that yield data suggesting two possible Holocene surface-
                    faulting events (West, 1994).

                    Continue another 2.5 miles to view the north branch of the North Flank fault zone (Bryant,
                    1992). This branch placed Permian Park City Formation on the south next to Tertiary
                    Wasatch Formation on the north. The south branch of the North Flank fault zone is
                    exposed another 0.5 miles south. There, the fault also placed the Park City Formation next
                    to the Tertiary Wasatch Formation; however, several small branches cut the older Paleozoic

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                   rocks tilting and deforming beds. Return to the junction of the Boy Scout Camp road
                   and USFS 058.

2.0      0.4       The road crosses onto the Tertiary Wasatch Formation.

2.3      0.3       Deadman Creek. The section of Deadman Creek from here northward to Mill Creek may
                   be controlled by a segment of the Bear River fault zone (West, 1994). Deadman Creek
                   flows nearly due north from here northward but south of here the creek swings abruptly
                   southeastward. The hills east of Deadman Creek contain the Tertiary Wasatch Formation.

3.1      0.8       Broad curve to left has road cut mapped as Tertiary Wasatch (Bryant 1992) that is capped
                   by thin gravel deposits.

3.4      0.3       Weathered Wasatch Formation in road cut on right.

3.7      0.3       West Carter Creek road on right. Stay on USFS road 058, North Slope road. Cross onto
                   Holocene alluvium-colluvium as road descends into Carter Creek.

4.1      0.4       Cross Carter Creek.

4.2      0.1       The road crosses back onto Wasatch Formation and parallels the contact between alluvium-
                   colluvium on left and Wasatch Formation on right.

5.0      0.9       The road cut on right is weathered Wasatch Formation overlain by thin gravel deposits of
                   uncertain age.

5.9      0.9       The road crosses onto alluvium-colluvium.

6.3      0.4       Junction of Mill Creek turn off. Stay left on North Slope road (USFS road 058). The low
                   pine-covered hills above valley floor are mapped as landslide deposits (Bryant, 1992).

6.7      0.4       Cross North Fork of Mill Creek. The road travels up landslide deposits.

8.2      1.5       The road cut contains weathered Wasatch Formation that is mantled with gravel deposits of
                   uncertain age. There are numerous slope failures that are likely in the Wasatch Formation.

8.8      0.6       Cross McKenzie Creek. The road travels on landslide deposits.

10.5     1.7       The road travels on landslide deposits; the subsurface trace of the Hogsback thrust fault is
                   mapped near here by Bryant (1992).

11.5     1.0       Elizabeth Ridge Pass (10,235 feet) is in Bishop Conglomerate. West (1993) mapped a fault
                   scarp that cuts the Bishop Conglomerate and Gilbert Peak erosion surface on Elizabeth
                   Ridge. The fault strikes N 70o W and is down to the south. West (1993) believes this fault
                   reflects normal faulting along the older Hogsback thrust. Drainage divide between Green
                   River and Great Basin drainages. Stay on USFS road 058.

11.6     0.1       To the right is a scenic view into the Blacks Fork drainage. Glacial deposits are in view as
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Dehler, Pederson, Sprinkel, and Kowallis, editors                              2005 Utah Geological Association Publication 33

                     well as steeply dipping Paleozoic rocks. In the trees are traces of the North Flank fault
                     zone. The fault placed Paleozoic rocks on south up against Wasatch Formation on north.

13.3      1.7       Road makes a wide hairpin turn to the right. Blacks Fork till is to the left of the road.

13.5      0.2       The road crosses onto landslide deposit that is likely failed Wasatch Formation and Smiths
                    Fork till. Road cut in bouldery landslide deposits as mapped by Munroe (2001).

14.1      0.6       Road travels on landslide deposits (Munroe, 2001) that likely includes failed Smiths Fork
                    till.

16.5      2.4       Junctions of East Fork and West Fork of Blacks Fork River and USFS road 070 to Lyman
                    Lake. Turn right and then left on road to East Fork of Blacks Fork. Road travels north
                    on landslide deposits (failed Smiths Fork till) and alluvium; note that West Fork of Black
                    Fork River on right has incised down through landslide deposits of Smiths Fork till.

18.8      2.3       Junction of East Fork of Blacks Fork road (USFS road 069). Turn right onto East Fork
                    road.

19.0      0.2       West Fork Bridge (West Fork of Blacks Fork River). Road is on alluvium and Smiths Fork
                    glacial till.

19.1      0.1       Junction of Middle Fork of Blacks Fork road (not numbered) on right. About 6 miles up
                    the Middle Fork road (traveling south) is the location for the Double Eagle Petroleum
                    exploration well. This well will spud in the Red Pine Shale and drill through the North
                    Flank fault into younger rocks. The target is Cretaceous Frontier and Dakota Sandstone.
                    We will take a short side trip to the well location if the well is drilling and road is
                    improved; otherwise, stay on East Fork road (USFS 069).

21.1      2.0       Road crosses first of two moraines of Smiths Fork age (Munroe, 2001).

21.4      0.3       Road crosses second of the two moraines of Smiths Fork age (Munroe, 2001).

22.1      0.7       Road crosses approximate subsurface trace of north branch of the North Flank fault (Bryant,
                    1992).

22.2      0.1       Road cut of Smiths Fork till.

22.8      0.6       STOP 2 – View of Red Pine Shale and Madison Limestone dipping steeply north. Above the
                    Madison are the Humbug and Doughnut Formations that form the strike valley. The south
                    branch of the North Flank fault placed the Mississippian Humbug-Doughnut Formations
                    up against the Tertiary Wasatch on north. Continue south on East Fork road (USFS road
                    069).

23.9      1.1       Cache Meadow; view of formation of Hades Pass and Red Pine Shale on ridge to the east.

24.3      0.4       Gate into trailhead parking area.


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Road Guide to the Geology of the Uinta Mountains for the 2005 UGA Field Conference   B,J. Kowallis, D.A. Sprinkel, J.L. Pederson, and C.M.

24.5     0.2       Parking area for trailhead and campground of East Fork of Blacks Fork River. The contact
                   between the Hades Pass Formation and overlying Red Pine Shale is seen on ridge to east. The
                   formation of Hades Pass forms resistant reddish cliffs of quartz sandstone. Turn around
                   and go back to junction of East Fork Road (USFS road 069) and the North Slope road
                   (USFS road 058).

30.1     5.6       Junction with USFS road 058 (North Slope road). Keep right and stay on USFS road 058,
                   (North Slope road).

30.7     0.6       Junction on right; the well graveled road to the north is USFS road 073 to Wyoming SR
                   414 and to Meeks Cabin. Turn right to stay on USFS road 058 to Hewinta Guard
                   Station. CAUTION: this section of USFS road is not well maintained and requires
                   high-clearance vehicles. There are places along this segment where 4-wheel drive
                   vehicles may be needed if the road is wet or damaged.

30.8     0.1       Cross Blacks Fork River and continue on USFS road 058. The road parallels lateral moraine
                   on left.

31.2     0.4       Road swings left and climbs Smiths Fork till.

31.5     0.3       Road junction on left. Stay to right on main road (USFS road 058).

32.9     1.4       Tertiary Wasatch Formation (weathered) in road cut. Note that the road has smoothed out a
                   bit where constructed on bedrock. The Wasatch Formation is thinly mantled with Smiths
                   Fork till in places.

33.2     0.3       Junction of small road on left. Stay to right on main road (USFS road 058).

33.3     0.1       Wasatch Formation thinly mantled with Smiths Fork till in road cut.

33.4     0.1       Cattle guard. Road travels across Wasatch Formation that is mantled with some thin till.

35.7     2.3       Cattle guard. The glacial till becomes thicker and more dominant from previous cattle
                   guard to here.

36.5     0.8       View to southeast of Gilbert Peak (13,442 feet). The Gilbert Peak erosion surface is the
                   planar surface to the left of Gilbert Peak. It is cut into the Uinta Mountain Group. Note the
                   road improves on approach to Hewinta Guard Station.

36.9     0.4       Junction with USFS road 074 on left. Keep right and stay on USFS road 058 to China
                   Meadows and Bridger Lake Campground. The road travels on glacial till.

37.0     0.1       Bridge crosses Steel Creek. Note that the road has significantly improved.

37.1     0.1       Junction of road on right to Hewinta Guard Station. Keep left on main road (USFS road
                   058).

37.5     0.4       Cattle guard.
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37.6      0.1       Cross West Fork of Smiths Fork. The road climbs a moraine and till.

39.0      1.4       Cattle guard and unnumbered road to north. Stay on main road (USFS road 058).

39.4      0.4       Junction of USFS road 075 to Mountain View, Wyoming. Stay on USFS road 058 to China
                    Meadows. Road crosses Gilbert Meadow, which contains alluvial-colluvial deposits.

40.8      1.4       Road cut in landslide deposits in Smiths Fork till.

41.5      0.7       Cattle guard.

42.5      1.0       Road cut in landslide deposits in Smiths Fork till. The road swings to the right and offers
                    a magnificent view of Gilbert Peak, which is the third highest peak in Utah at 13,442 feet,
                    and Kings Peak, which is the highest point in Utah at 13,528 (figure 3.8). Note the Gilbert
                    Peak erosion surface.

43.9      1.4       STOP 3 – Junction of China Meadows Campground and view of China Meadows. The
                    subsurface trace of the North Flank fault zone cuts through here. The Madison Limestone
                    can be seen to the southeast and is on the up thrown block. The Bishop Conglomerate
                    is mapped by Bryant (1992) as the brown-colored ridge to the northeast. Smiths Fork
                    moraines are along meadows. A small terminal (recessional?) moraine is at north end of
                    China Meadows. The road cut at intersection is weathered Wasatch Formation capped by
                    Smiths Fork till. Turn left on USFS road 058 to Mountain View, Wyoming, and Bridger
                    Lake campground.

44.1      0.2       Cross East Fork of Smiths Fork. Moraine(?) is cut through by East Fork of Smiths Fork
                    River. The road travels on landslide deposits in Smiths Fork till down most of the Smiths
                    Fork drainage to nearly two miles north of the state line.

45.4      1.3       Junctions on left to Marsh Lake
                    Campgrounds. Stay on USFS road
                    058 to Mountain View, Wyoming.

47.2      1.7       Junction on right to Bridger Lake
                    Campground. Stay on USFS road
                    058 to Mountain View, Wyoming.

47.8      0.6       Access to Stateline Campground on
                    left and start of paved road. Stay on
                    USFS road 058 to Mountain View,
                    Wyoming.

48.1      0.3       End of paved road. Landslide
                    deposits in Smith Fork till in road        Figure 3.8. View eastward of Gilbert Peak (on north) and Kings Peak (on
                    cut on right.                              south above vehicle). Gilbert Peak is the third highest peak in Utah at
                                                               13,442 feet and Kings Peak is the highest point in Utah at 13,528. Note
                                                               the planar surface of the Gilbert Peak erosion surface at Gilbert Peak.

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48.3     0.2       Cattle guard.

48.9     0.6       Stateline. Welcome to Wyoming!

49.8     0.9       The road crosses moraine deposits likely associated with the Smiths Fork glacial event.

50.7     0.9       Junction on right to Henrys Fork. Stay on USFS road 058 to Mountain View, Wyoming.
                   The road is constructed on Blacks Fork till (Munroe, 2001).

51.5     0.8       The road travels on alluvial-gravel deposits of uncertain age.

51.8     0.3       Junction on left to Deadhorse trailhead. Stay on USFS road 058 to Mountain View,
                   Wyoming.

52.4     0.6       Cattle guard.

52.9     0.5       STOP 4 – Overview of glacial deposits at mouth of Smiths Fork. View to the west-southwest
                   of Smiths Fork till and terminal moraine in the valley bottom. Smiths Fork outwash is
                   deposited north of the moraine. The older Blacks Fork till is deposited above the valley
                   bottom along the sides of the modern drainage. Continue north on USFS road 058 to
                   Mountain View, Wyoming.

54.5     1.6       Boundary of Wasatch National Forest and cattle guard. Begin oiled road.

56.1     1.6       Rounded hills to left and right are dissected alluvial-gravel deposits of uncertain age.

57.5     1.4       Road curves to right around the edge of alluvial-gravel deposits of uncertain age.

57.8     0.3       Cattle guard.

58.7     0.9       Cattle guard.

60.8     2.1       Outcrops to right are Tertiary Bridger Formation capped by alluvial-gravel deposits of
                   uncertain age.

63.0     2.2       Stop sign and junction with Wyoming SR 410 and Uinta County road 283. Go south on
                   SR 410 to Mountain View, Wyoming.

69.0     6.0       Junction of Wyoming SR 411 on left. Stay on SR 410 to Mountain View.

69.2     0.2       Cross Smiths Fork River.

69.4     0.2       Enter Mountain View, Wyoming.

70.0     0.6       Junction with SR 414. Turn left to return to Salt Lake City.

E N D O F R O A D LO G

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                       RE FE RE N CE S
                     (North Slope Road)

Bradley, M.D., 1995, Timing of the Laramide rise
   of the Uinta Mountains, Utah and Colorado:
   Wyoming Geological Association 1995 Field
   Conference Guidebook, p. 31-44.
Bryant, Bruce, 1992, Geologic and structure maps of
   the Salt Lake City 1o x 2o quadrangle, Utah and
   Wyoming: U.S. Geological Survey Miscellaneous
   Investigations Series Map I-1997, 2 plates, scale
   1:250,000.
Hansen, W.R., 1975, The geologic story of the Uinta
   Mountains, U.S. Geological Survey Bulletin
   1291, 144 p.
Munroe, J.S., 2001, Late Quaternary history of the
   northern Uinta Mountains, northeastern Utah:
   Madison, University of Wisconsin-Madison,
   Ph.D. dissertation, 398 p.
West, M.W., 1993, Extensional reactivation of
   thrust faults accompanied by coseismic surface
   rupture, southwest Wyoming and north-central
   Utah: Geological Society of America Bulletin, v.
   105, no. 9, p. 1137-1150.
West, M.W., 1994, Seismotectonics of north-
   central Utah and southwestern Wyoming: Utah
   Geological Survey Special Studies 82, 93 p.




                                                    447
Timothy O’Sullivan, 1869




Jeffrey S. Munroe, 2003. Ridgeline southwest of Ryder Lake




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• Red Pine Shale • vase-shaped microfossils • Chuaria • Bavlinella • biomarkers • Tintic Quartzite • Neoglacial •




Formation • Neoproterozoic • Altonah moraine • dinosaur tracks          •   undifferentiated highlands     •   steppe   • Asphalt Ridg




been produced by the degradation of a great upheaved block having its axis in an east and west direction....From the axis on either




 curve to the north and south for many miles until the flanks of the range are reached, where the beds are seen to drop down by abrupt fl




maximum displacement are parallel with the axis.   [which]...suggests the application of vertical pressure from below.”    •   Agassiz




•   “We have an unknown distance yet to run, an unknown river to explore. What falls there are, we know not; what rocks beset




walls ride over the river, we know not. Ah, well! we may conjecture many things. The men talk as cheerfully as ever; but to me th




ghastly.” - John Wesley Powell, (1834-1902) • Laramide uplift • Stillwater Tunnel • Madison Limestone • Clay




eidy Peak • “...the Uinta upheaval began at the close of Mesozoic time, and has continued intermittently near to the present, and




 suffered a degradation in areas of maximum erosion of no less than 30,000 feet....” •          Duchesne River •        Upper Cretaceou




roup • Dakota Sandstone reservoir     •   Cretaceous Frontier Formation     •   Morrison Formation    •   breached surface anticline




 colored strata • Mowry Sea • Dakota Sandstone reservoir • Red Creek                • Tertiary Wasatch and Fort Union formatio




on • Quartzite • Sandstone • Shale •           Browns Park Formation • Uinta Mountain Group • Jesse Ewing Canyon Form




 Surface • Bishop Conglomerate • Smiths Fork glaciation • Red Pine Shale • vase-shaped microfossils • Chuaria • Bavline




zite • Neoglacial • outwash plain • tarn       • Lodore Formation • Neoproterozoic • Altonah moraine • dinosaur tracks              •




eppe   • Asphalt Ridge •“The Uinta Mountains have been produced by the degradation of a great upheaved block having its ax

								
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