TECTONIC HISTORY OF NEWARK RIFT BASIN AND THE EASTERN

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					                                                                                        Olsen (1999)


TECTONIC HISTORY OF
 ECTONIC ISTORY OF                                                           Rift zone


THE NEWARK RIFT
THE EWARK IFT                                               CAMP
                                                            & rift
                                                            zone
BASIN AND THE
  ASIN AND THE
EASTERN NORTH
  ASTERN ORTH                                                                   CAMP

AMERICAN PASSIVE
  MERICAN ASSIVE
CONTINENTAL MARGIN
  ONTINENTAL   ARGIN
Roy W. Schlische, Martha Oliver Withjack, Mark S. Baum
             Dept. of Geological Sciences
                  Rutgers University



   In this presentation I review the tectonic history of the Newark basin, focusing
   on the deformational events that have created various structures that are
   important to understanding the basin’s hydrogeology. At the end of the talk, I
   discuss the similarities and differences between the Newark basin and the
   other basins of the eastern North American rift system. These rift basins
   formed as a result of the breakup of Pangea.

   Figure modified from Olsen, P. E., 1999, Giant lava flows, mass extinctions, and mantle
   plumes: Science, v. 284, p. 604-605.




                                                                                                       1
   N                                                             Continental
 ~400 km
                                                                 margin of
 North                                         +
                                                +
                                                 ++              eastern
                                              +
America
                               +   ++
                                        +
                                            +
                                             +
                                                 Newark          North
                            ++

                       +
                        +
                         ++
                            +

                                   ++
                                                 Rift            America
                                 ++
                      +
                       +
                       +
                              +
                               +                 Basin
                      +       +
                     +       +
                    +       +
                    +      +
                   +      +
                  +       +
                 +       +
                +
              ++        +
                       +
         + ++
                     +
                      +                           North     ++
                                                            +
                                                                 East Coast Magnetic Anomaly
                    +
                                                 Atlantic   +
                                                            +
                                                             +
                                                                 Blake Spur Magnetic Anomaly
                                                 Ocean           Early Mesozoic rift basins

                                                                 Paleozoic compressional structures




 This figure shows some of the large-scale tectonic features of the eastern
 North American continental margin. The rift basins follow the trend of
 Paleozoic compressional structures. The East Coast Magnetic Anomaly
 approximates the continent-ocean boundary. These lineations are the oldest
 dated magnetic anomalies at 155 Ma. The Blake Spur magnetic anomaly is
 related to a ridge jump during the early phases of seafloor spreading. The
 oldest oceanic crust is located between ECMA and BSMA.

 Figure modified from Withjack, M.O., Schlische, R.W., and Olsen, P.E., 1998,
 Diachronous rifting, drifting, and inversion on the passive margin of central eastern North
 America: An analog for other passive margins: AAPG Bulletin, v. 82, p. 817-835.




                                                                                                      2
    E. Jurassic synrift strata &
    CAMP lava flows                        Newark basin
    E. Jurassic diabase sheets

   L. Triassic Passaic Fm.

   L. Triassic Lockatong Fm.

   L. Triassic Stockton Fm.
                                                                                 Pr
   Paleozoic prerift strata &
   Precambrian basement

                                  NB-1
                                               Ps
                                    Ps




                    H


                                                                     25 km            N

The simplified geologic map shows the border-fault system on the NW
margin of the basin. Synrift strata dip toward the BFS. The tectonic history of
the Newark basin is relatively well constrained because of field data, deep
drill-hole data, and seismic-reflection profiling, especially line NB-1.

Figure based on Schlische, R.W., 1992, Structural and stratigraphic development of the
Newark extensional basin, eastern North America; Implications for the growth of the basin
and its bounding structures: Geological Society of America Bulletin, v. 104, p. 1246-1263,
and Withjack, M.O., Schlische, R.W., and Olsen, P.E., 2002, Rift-basin structure and its
influence on sedimentary systems, in Renaut, R., and Ashley, G.M., eds., Sedimentation in
Continental Rifts: SEPM Special Publication 73, p. 57-81.




                                                                                             3
Seismic line NB-1
NW                                                                                           SE
                                                                                                  0

                                                                                                  1

                                                                                                  2

                                                                                                  3
     5 km
                                                                                                  4




 Seismic line NB-1 shows the half-graben geometry of the basin, the relatively
 low-angle BFS dipping to the SE, and synrift strata dipping to the NW.

 Figure modified from: Bally, A.W., Withjack, M.O., Meisling, K.E., and Fisher, D.A.,
 1990, Seismic expression of structural styles: Geological Society of America Short Course
 Manual.




                                                                                                      4
    Seismic line NB-1
    NW              Cabot #1                                                                    SE
0

1

2

3
                                                                          5 km
4
seconds E. Jurassic synrift strata &                                  1:1 at 5.5 km/s
          CAMP lava flows
          L. Triassic Passaic Fm.
                                              Border-                Flemington/Furlong
          L. Triassic Lockatong Fm.           fault zone                fault system
          L. Triassic Stockton Fm.

          Conglomeritic facies

          Unexposed Triassic synrift strata

          Paleozoic prerift strata

          Precambrian basement




     The interpretation of seismic line NB-1 is constrained by surface geology and
     the Cabot #1 well. The SE dipping reflections in the basement are Paleozoic
     compressional structures, some of which were reactivated to form the BFS. In
     the next set of slides, I outline the geologic history by showing sequential
     restorations of seismic line NB-1.

     Figure modified from: Withjack, M.O., Schlische, R.W., and Olsen, P.E., 2005, Triassic-
     Jurassic rift basins of eastern North America," in Roberts, D.G., and Bally, A.W., eds.,
     Principles of Phanerozoic Regional Geology, Volume 1: New York, Elsevier, in press.




                                                                                                     5
Late Triassic (?)
• Onset of rifting
• Onset of rifting
• Reactivation of Paleozoic compressional
• Reactivation of Paleozoic compressional
     structures as border-fault zone
     structures as border-fault zone
                        NW                                                     SE

            Eroded section
                                                                 Eroded
                                                                 section

                            5 km




 This restoration shows the geometry of the Newark basin at the onset of
 rifting. Gray represents Precambrian basement rocks, and purple represents
 Paleozoic prerift rocks.

 Figure modified from: Withjack, M.O., Schlische, R.W., and Olsen, P.E., 2005, Triassic-
 Jurassic rift basins of eastern North America," in Roberts, D.G., and Bally, A.W., eds.,
 Principles of Phanerozoic Regional Geology, Volume 1: New York, Elsevier, in press.




                                                                                            6
Late Triassic (?)
• Deposition of oldest synrift strata in narrow basin
• Deposition of oldest synrift strata in narrow basin
• Pronounced thickening toward border-fault zone
• Pronounced thickening toward border-fault zone

                     NW                                                         SE

         Eroded section
                                                                 Eroded
                                                                 section

                         5 km




  The oldest synrift strata accumulated in a narrow basin and display
  pronounced thickening toward the BFS. The exact age of these oldest synrift
  strata is not known because these strata are nowhere exposed at the surface.

  Figure modified from: Withjack, M.O., Schlische, R.W., and Olsen, P.E., 2005, Triassic-
  Jurassic rift basins of eastern North America," in Roberts, D.G., and Bally, A.W., eds.,
  Principles of Phanerozoic Regional Geology, Volume 1: New York, Elsevier, in press.




                                                                                             7
             Stage 1:
              Initial
             Stockton
            deposition Stage 2:
                                     Reconstruction
                          End
                        Stockton        Stage 3:
                       deposition         End
                                       Lockatong
                                       deposition
                                                        Stage 4:
                                                      End Passaic
                                                       deposition


                                                                 Stage 5:
                                                                   End
                                                                  CAMP




                                                                             Stage 6:
                                                                                After
                                                                            additional
                                                                            tilting and
                                                                              erosion




During this period, the basin likely consisted of a number of isolated
subbasins that eventually combined to form the Newark basin as the border
faults linked together.

Figure modified from: Schlische, R.W., 1992, Structural and stratigraphic development of
the Newark extensional basin, eastern North America; Implications for the growth of the
basin and its bounding structures: Geological Society of America Bulletin, v. 104, p. 1246-
1263.




                                                                                              8
Late Triassic
• Deposition of Stockton Fm. in wider basin
• Noticeable thickening toward border-fault zone
• Little, if any, displacement on intrabasin fault


                    NW                               Eroded section              SE

         Eroded section



                        5 km




  In the Late Triassic, the Stockton Formation (shown in light green)
  accumulated in a widening basin and displays noticeable thickening toward
  the BFS. There was little, if any, displacement on the Flemington fault.

  Figure modified from: Withjack, M.O., Schlische, R.W., and Olsen, P.E., 2005, Triassic-
  Jurassic rift basins of eastern North America," in Roberts, D.G., and Bally, A.W., eds.,
  Principles of Phanerozoic Regional Geology, Volume 1: New York, Elsevier, in press; and
  Schlische, R.W., and Withjack, M.O., 2005, The early Mesozoic Birdsboro central Atlantic
  margin basin in the Mid-Atlantic region, eastern United States: Discussion: Geological
  Society of America Bulletin, v. 117 (n. 5/6), in press.




                                                                                             9
Late Triassic
• Deposition of Lockatong Fm. in wide basin
• Subtle thickening toward border-fault zone
• Little, if any, displacement on intrabasin fault


                 NW                                         Eroded section SE

      Eroded section




                      5 km




  The Lockatong Formation accumulated in a wide basin and displays subtle
  thickening toward the border-fault zone. The best evidence of syndepositional
  faulting comes from field and core data.

  Figure modified from: Withjack, M.O., Schlische, R.W., and Olsen, P.E., 2005, Triassic-
  Jurassic rift basins of eastern North America," in Roberts, D.G., and Bally, A.W., eds.,
  Principles of Phanerozoic Regional Geology, Volume 1: New York, Elsevier, in press.




                                                                                             10
NW                   SE




                       ) y
        (b ram




                     (N ser
          y)                                                   Lockatong Formation
                      ur
           y
         B




                  N




                                 Tohickon Mb
                                         Measured outcrop section                Core site



                                 05°
                              0.
                                               Skunk0.25° Mb
                                 °
                                                    Hollow
                              0.1



                                                           1°
                                                         0.5°




                                                                      by




                 msgc

                 30                                                    N
                     meters




                 0
                                                               N                      25 km
     msgc    VE=1000x



       The width of the Lockatong Formation (a proxy for its thickness) increases
       from the lateral edges of the basin toward the basin center. Core-to-outcrop
       correlations show thickening from Nursery to Byram. Differential tilting of
       about 0.1° can account for this thickening toward the BFS.

       Figure modified from: Schlische, R.W., and Withjack, M.O., 2005, The early Mesozoic
       Birdsboro central Atlantic margin basin in the Mid-Atlantic region, eastern United States:
       Discussion: Geological Society of America Bulletin, v. 117 (n. 5/6), in press.




                                                                                                    11
Late Triassic
• Deposition of Passaic Fm. in very wide basin
• Very subtle thickening toward border-fault zone
• Little, if any, displacement on intrabasin fault

               NW                                                                        SE
                                                         Eroded          section
   Eroded section




                   5 km




  The Passaic Formation accumulated in an even wider basin than the
  Lockatong Formation, and displays very subtle thickening toward the BFS.
  Again, the best evidence of syndepositional faulting comes from core and
  outcrop data.

  Figure modified from: Withjack, M.O., Schlische, R.W., and Olsen, P.E., 2005, Triassic-
  Jurassic rift basins of eastern North America," in Roberts, D.G., and Bally, A.W., eds.,
  Principles of Phanerozoic Regional Geology, Volume 1: New York, Elsevier, in press.




                                                                                              12
 Passaic Formation




                                                                                                                                             et
                                                                                             W                                                     E




                                                                                                                                                    ) s
                                                                                                                f) d




                                                                                                                                      (S ers


                                                                                                                                                  (R ger
                                                                                                             (m lfor




                                                                                                                                        m


                                                                                                                                                   ut
                                                                                                                                        )
                                                                                                               i
                                                                                                              M




                                                                                                                                So


                                                                                                                                               R



                                                                                                                                                            Metlars Mb
                       Measured outcrop section                    Core site


                                                    mf




                                                                                                                                                                           Livingston Mb
                                       Pk                                                                       °
                                                                                                             05
                              ty                                                                         0.
                                                              Pk




                                                                                                            °
                                                                                                         0.1
                                                                       S




                                                                                                                    0 .2 5 °
                                                                                                                       1°
                                                                                                                    0.5°
                                                                                R
                                                                           Pk
                                                    T

                           N       Pk: Perkasie Member                25 km
                                                                                                                               msgc
SW                       NE
                          f) d




                                   SW                                           NE
                       (m lfor
            ) ort




                                                                                                                                                             Perkasie Mb
                                                          ) le
                                                        (T svil




                                                                                 ) s
        (ty rsp




                          i
                        M




                                                                               (R ger
                                                         tu
          le




                                                                                ut
                                                    Ti
      Ty




                                                                               R




                                                                                        Perkasie Mb
                                               OC
                                    Perkasie Mb




                                                                                                                                30
                                     core




                                                                                                                                             msgc




                                                                                                                                    meters
                                                                               msgc

                                                msgc        VE=1000x                                                            0
     msgc              msgc
            VE=1000x                                                                                  msgc      VE=1000x



      The Passaic Formation thickens from the SW edge of the basin toward the
      basin center as well as the NE edge to the basin center. Strata also thicken
      toward the BFS. The differential tilting required to account for the tilting is
      ~0.05°.

      Figure modified from: Schlische, R.W., and Withjack, M.O., 2005, The early Mesozoic
      Birdsboro central Atlantic margin basin in the Mid-Atlantic region, eastern United States:
      Discussion: Geological Society of America Bulletin, v. 117 (n. 5/6), in press.




                                                                                                                                                       13
             Stage 1:
              Initial
             Stockton
            deposition Stage 2:
                                     Reconstruction
                          End
                        Stockton        Stage 3:
                       deposition         End
                                       Lockatong
                                       deposition
                                                        Stage 4:
                                                      End Passaic
                                                       deposition


                                                                 Stage 5:
                                                                   End
                                                                  CAMP




                                                                             Stage 6:
                                                                                After
                                                                            additional
                                                                            tilting and
                                                                              erosion




The reconstruction shows the Newark basin likely achieved its greatest width
during the deposition of the Passaic Formation. During the Early Jurassic, the
intrabasinal faults became active and strata accumulated in a narrower region
compared to latest Triassic strata.

Figure modified from: Schlische, R.W., 1992, Structural and stratigraphic development of
the Newark extensional basin, eastern North America; Implications for the growth of the
basin and its bounding structures: Geological Society of America Bulletin, v. 104, p. 1246-
1263.




                                                                                              14
Early Jurassic
• Deposition of CAMP lava flows & synrift strata
• Intrusion of diabase sheets
• Significant displacement on border-fault zone
   and intrabasin faults
• Tilting of synrift strata toward border-fault zone
   NW                                                                                   SE
                    Eroded section




       5 km




  The Early Jurassic witnessed the eruption of CAMP basalts and intrusion of
  diabase sheets. There was significant displacement on both the BFS and the
  intrabasinal faults. Most of the tilting of the basin fill toward the NW occurred
  during or after the Early Jurassic.

  Figure modified from: Withjack, M.O., Schlische, R.W., and Olsen, P.E., 2005, Triassic-
  Jurassic rift basins of eastern North America," in Roberts, D.G., and Bally, A.W., eds.,
  Principles of Phanerozoic Regional Geology, Volume 1: New York, Elsevier, in press.




                                                                                             15
                                                                                              Age (Ma)
Earliest




                                          235



                                                                                            225



                                                                                                         215

                                                                                                               210

                                                                                                                     205

                                                                                                                           200
                                                                                      230



                                                                                                  220




                                                                                                                                 195
                                                 Cumulative Stratigraphic Thickness (km)
Jurassic                              0
                                                                                                        DR
                                                                                                                       D

accelerated                           1                                                                        D
                                                                                                               V H
                                      2
subsidence                                  R
                                                                                                                F
                                      3
                                     4
                                                Newark
                                     5
                                                                                                               C
                                      6

                                      7
                                                                                                        CAMP
                                                                                                        extrusive
                                      8                                                                 interval


 This graph shows cumulative stratigraphic thickness plotted against geologic
 age for a number of rift basins. The Culpeper, Newark, Hartford, Deerfield
 and Fundy basins all show accelerated subsidence during the CAMP extrusive
 interval.

 Figure modified from: Schlische, R.W., and Anders, M.H., 1996, Stratigraphic effects and
 tectonic implications of the growth of normal faults and extensional basins, in Beratan,
 K.K., ed., Reconstructing the Structural History of Basin and Range Extension Using
 Sedimentology and Stratigraphy: Geological Society of America Special Paper 303, p. 183-
 203.




                                                                                                                                 16
Stress state at 200 Ma
                  Rift zone

    CAMP
    & rift
    zone                                         North
                                                 America
                    CAMP



                                                                               Atlantic
                                                                               Ocean


                                                                                  N
                                                                              ~400 km


 Dikes intruded during the earliest Jurassic provide a snapshot of the stress
 state about 200 million years ago. Dikes in the vicinity of the Newark basin
 indicate WNE-ESE extension. Farther north, the extension direction was NW-
 SE. In the south, the extension direction was NE-SW. This extension direction
 is incompatible with rifting, and is one of several pieces of evidence
 indicating that rifting in the south had ended prior to this time.

 Figure modifed from: Schlische, R.W., Withjack, M.O., and Olsen, P.E., 2003, Relative
 timing of CAMP, rifting, continental breakup, and inversion: tectonic significance, in
 Hames, W.E., McHone, G.C., Renne, P.R., and Ruppel, C.R., eds., The Central Atlantic
 Magmatic Province: Insights from Fragments of Pangea: American Geophysical Union
 Monograph 136, p. 33-59.




                                                                                          17
Oblique faulting                                                                                             Diabase
                                                                                                             dike
                                                                                                                                                          10




                                                                                         Thrust                                                                14

                                                                                         fault
                                                                                                                                                               11
                                                     Strike-slip                                                                   18
                                                                                                                               7                 9         10
                                                     fault
                              Normal                                                                                                                 10

                              fault                                                                                 9         11    10
                                                                                                                                         7
                               (dashed where
                               inferred)
                                                                                                                                             8
                                                                                                   26
                                                                                                               13


23
     Strike and dip of
     bedding
                                                                                          6
                                                                                                                                                                    N
                                                              15
                                                                         41                   10               10

                                                                        42
                                                                                                                    12
                                                                                                                          5 cm
                                                                                                                         14


                                                         16
                                                                                              25
                                                                              10
                                                                   20
                                                                                                        10
                                                                                   25
                                               16
                                                                                    20             10
                                                         13
                                    18
                                                                                         15
                    40                                              13
                               21
               23        31              25
         21

                              12
                                                12




25 km


 The WNW-ESE extension direction indicated by the dikes is oblique to many
 segments of the BFS, indicating that at least parts of the BFS underwent
 oblique slip. As indicated by the results of scaled physical modeling, oblique
 extension produces two sets of faults, one parallel to the BFS and one
 subperpendicular to the displacement direction. Large segments of the
 intrabasinal faults in the Newark basin are oblique to the BFS.
 Geologic map modified from: Schlische, R.W., 1992, Structural and stratigraphic
 development of the Newark extensional basin, eastern North America; Implications for the
 growth of the basin and its bounding structures: Geological Society of America Bulletin, v.
 104, p. 1246-1263.
 Experimental model modified from: Schlische, R.W., Withjack, M.O., Ackermann, R.V.,
 and Clifton, A.E., 2003, Controls on the growth and maximum size of fault arrays and fault
 segments--Insights from experimental clay models: Eos, Transactions, American
 Geophysical Union, v. 84 (46), Fall Meeting Supplement, Abstract T21B-05, p. F1358.



                                                                                                                                                                        18
Middle Jurassic (?) and younger
• Cessation of rifting
• Cessation of rifting
• Major folding near border-fault zone
• Major folding near border-fault zone
• Significant uplift and erosion
• Significant uplift and erosion
   NW                                     Seismic Line NB-1                              SE




       5 km




  During Middle Jurassic time, rifting ended. The basin then underwent
  significant uplift and erosion along with major folding near the BFS, part of
  basin inversion.

  Figure modified from: Withjack, M.O., Schlische, R.W., and Olsen, P.E., 2005, Triassic-
  Jurassic rift basins of eastern North America," in Roberts, D.G., and Bally, A.W., eds.,
  Principles of Phanerozoic Regional Geology, Volume 1: New York, Elsevier, in press.




                                                                                              19
             Stage 1:
              Initial
             Stockton
            deposition Stage 2:
                                     Reconstruction
                          End
                        Stockton        Stage 3:
                       deposition         End
                                       Lockatong
                                       deposition
                                                        Stage 4:
                                                      End Passaic
                                                       deposition


                                                                 Stage 5:
                                                                   End
                                                                  CAMP




                                                                             Stage 6:
                                                                                After
                                                                            additional
                                                                            tilting and
                                                                              erosion




The uplift and erosion caused the basin to become narrower and shorter.

Figure modified from: Schlische, R.W., 1992, Structural and stratigraphic development of
the Newark extensional basin, eastern North America; Implications for the growth of the
basin and its bounding structures: Geological Society of America Bulletin, v. 104, p. 1246-
1263.




                                                                                              20
                                                                   Clay
                                                                   models of
                                                                   extension
                                                                   and
                                                                   inversion
                                                                  • Basin-scale
                                                                    folding (evidence
                                                                    largely removed
                                                                    by erosion)
                                                                  • Inversion-related
                                                                    tilting

Eisenstadt & Withjack (1995)
Eisenstadt & Withjack (1995)

     Experimental models show that basin inversion results in basin-scale folding
     and additional tilting of the basin fill. Evidence for basin-scale folding is
     largely removed by erosion.

     Figure modified from: Eisenstadt, G., and Withjack, M.O., 1995, Estimating inversion:
     results from clay models, in Buchanan, J.G., and Buchanan, P.G., eds., Basin Inversion:
     Geological Society Special Publication 88, p. 119-136.




                                                                                               21
Inversion structure?
NW                                                         SE



                                       5 km

                                                                                 Pr




                                             Ps
                                  Ps




                H

                                                                    25 km             N
 Fault-parallel folds may be related to inversion. It is very difficult to produce
 this geometry solely as a result of extensional fault movements.

 Figure modified from: Schlische, R.W., 1992, Structural and stratigraphic development of
 the Newark extensional basin, eastern North America; Implications for the growth of the
 basin and its bounding structures: Geological Society of America Bulletin, v. 104, p. 1246-
 1263.




                                                                                               22
Folds in SW Newark basin


                                                                     Pr




                             NB-1
                                        Ps
                               Ps




                 H


                                                          25 km           N

 Fault-perpendicular folds may also have been amplified during inversion.




                                                                              23
Folds in SW
Folds in SW
Newark basin
Newark basin
                                                    18

                            N                            12

                    50                 30 30                       12
                          43
         26                                               20
                   25
                          35
                                                   15



                 5 km                                 • Steep dips
                                                      • Axial-planar cleavage


 These folds have axes that are subperpendicular to the BFS. Bedding dips can
 be quite steep, especially in proximity to the BFS. Some of the folds also
 contain axial-planar cleavage.

 Figure modified from: Schlische, R.W., 1992, Structural and stratigraphic development of
 the Newark extensional basin, eastern North America; Implications for the growth of the
 basin and its bounding structures: Geological Society of America Bulletin, v. 104, p. 1246-
 1263.




                                                                                               24
Growth folding
                              7.6 m

                                                                18

                                        N                             12

                               50                  30 30                        12
                                      43
                     26                                               20
                               25
                                      35
5.1 m                                                           15


                                                                            9.2 m
                            5 km


 These folds likely initiated during the extensional phase. Stratal marker units
 thicken from the limbs of the Jacksonwald syncline toward its hinge.

 Figure modified from: Schlische, R.W., 1992, Structural and stratigraphic development of
 the Newark extensional basin, eastern North America; Implications for the growth of the
 basin and its bounding structures: Geological Society of America Bulletin, v. 104, p. 1246-
 1263.




                                                                                               25
                                              18
                                                             Growth folding
                        N                          12

          50                             30
                                        30              12
               43
   26                                              20
          25
               35
                                              15

                                                                               Reynolds (1994)
        5 km
                                                             1 km
                                        SSW                                              NNE
                                    0
               Travel Time (secs)
                   Two-way




                                    1


                                                               Border-fault system
                                2

A seismic line shot parallel to the BFS shows the Lockatong Formation
thinning toward the crest of the Sassamannsville anticline. These folds are
likely fault-displacement folds in which the synclines formed from locally
higher fault displacements and anticlines formed from locally lower fault
displacements.

Figure modified from: Schlische, R.W., 1992, Structural and stratigraphic development of
the Newark extensional basin, eastern North America; Implications for the growth of the
basin and its bounding structures: Geological Society of America Bulletin, v. 104, p. 1246-
1263; and Reynolds, D.J., 1994, Sedimentary basin evolution: tectonic and climatic
interaction [Ph.D. thesis]: New York, Columbia University.




                                                                                                 26
Rotation during inversion?
 15°-20° counterclockwise
   rotation (Kodama et al., 1994)
            (Kodama et al., 1994)


                                                         18
                                                               12
                                 N
                        50                   30 30                       12
                               43
              26                                                20
                        25
                               35
                                                         15



                     5 km

 Some paleomagnetic data from the Sassamannsville syncline indicate 15-20°
 of counterclockwise rotation resulting from a left-lateral shearing component
 along the BFS.

 Figure modified from: Schlische, R.W., 1992, Structural and stratigraphic development of
 the Newark extensional basin, eastern North America; Implications for the growth of the
 basin and its bounding structures: Geological Society of America Bulletin, v. 104, p. 1246-
 1263.
 Kodama, K.P., Hedlund, C., Gosse, J., and Strasser, J., 1994, Rotated paleomagnetic poles
 from the Sassmansville syncline, Newark basin, southeastern Pennsylvania: Journal of
 Geophysical Research, v. 99, p. 4643-4653.




                                                                                               27
NE-SW shortening

                                                         18
                                                               12
                                 N
                        50                   30 30                       12
                               43
              26                                                20
                        25
                               35
                                                         15



                     5 km


 The shortening direction during inversion was NE-SW, which is consistent
 with the orientation of the axial-planar cleavage and the inferred CCW
 rotation indicated by the paleomagnetic data from the Sassamannsville
 syncline.

 Figure modified from: Schlische, R.W., 1992, Structural and stratigraphic development of
 the Newark extensional basin, eastern North America; Implications for the growth of the
 basin and its bounding structures: Geological Society of America Bulletin, v. 104, p. 1246-
 1263.




                                                                                               28
Fractures
formed during
shortening




El Tabakh et al. (1998)
El Tabakh et al. (1998)



  Horizontal shortening also produced horizontal veins filled with gypsum that
  cross-cut tilted bedding, indicated that they are late-formed structures.

  From El-Tabakh, M., Schreiber, B.C., and Warren, J.K., 1998, Origin of fibrous gypsum in
  the Newark rift basin, eastern North America: Journal of Sedimentary Research, v. 68, p.
  88-99.




                                                                                             29
Regional geology

                                      220




                                                               200




                                                                                                                                150


                                                                                                                                            140

                                                                                                                                                       130
                                                       210




                                                                            190




                                                                                           170

                                                                                                          160




                                                                                                                                                                                                        120
     260




                                                                                    180
                   230




                                                                                                                                                                                                                    110

                                                                                                                                                                                                                          100
                                                                                                                                                                                                                          Ma
         ?                                 ?                                                                                                                  ?     N




                                                                                                                                                                                                                                Segment
                                                                                                                                                                                                                                Northern
         ?                                 ?                                                                                                           Jeanne d'Arc
                                    ?                                                                                                         S
         ?                                                                           Orpheus
                                                                        Postrift?
                                           ?                                         Mohican
 ?                                                                Fundy




                                                                                                                     M-25 Segment




                                                                                                                                                       Oldest oceanic crust (linear extrapolation)
     ?                                                               Argana




                                                                                                           Central
                                                                  Deerfield
                                                                  Hartford




                                                                                                                                                                                                              M-0
                                               ?                  Pomperaug
           ?                                                      NEWARK
                                  ?                               Gettysburg
                                                                                                                                    Fluvial clastics                                                  Marine postrift
                         ?                                        Culpeper
                                                             Taylorsville                                                           Shallow lacus-                                                    Marine synrift
                                                                                                                                    trine clastics

                                                                                           Southern
                                                                                           Segment
                                                             Richmond                                                               Deep lacus-


                                                                                              BSMA
                                                                                                                                    trine clastics                                                    Evaporites
                                                             Norfolk
                                                                                                                                    Coals                                                             CAMP basalts
                                                             Farmville
                                                             Danville                                                                 Potential range of rift /
                         ?                                   Deep River                                                               drift transition
                     ?                ?            ?          South Georgia
                               M. Trias.
               Permian




                                                                                                Middle
                                                                                               Jurassic
                             Triassic
                                 Late




                                                                           Early
                                                                        Jurassic




                                                                                                                 Late
                                                                                                             Jurassic




                                                                                                                                                                                                     ceous
                                                                                                                                                                                                      Early
                                                                                                                                                                                                     Creta-
 I now focus on the regional context of Newark basin. The Newark basin is
 located in the central segment of the Atlantic continental margin. All basins in
 this segment contain both Late Triassic and Early Jurassic strata. Basins in the
 southern segment contain only Triassic strata, indicating that rifting likely
 ended there earlier than in central segment. In the northern segment, rifting
 continued through the Late Jurassic. Although there is a large uncertainty, the
 rift-drift transition was diachronous from south to north. Much of the
 uncertainty results from the fact that the oldest postrift strata are poorly
 sampled, and the oldest oceanic crust is not directly dated. The oldest postrift
 strata in Morocco suggest that drifting in the central segment may have begun
 as early as the late Early Jurassic.

 Figure modified from: Withjack, M.O., Schlische, R.W., and Olsen, P.E., 2005, Triassic-
 Jurassic rift basins of eastern North America," in Roberts, D.G., and Bally, A.W., eds.,
 Principles of Phanerozoic Regional Geology, Volume 1: New York, Elsevier, in press.

                                                                                                                                                                                                                           30
Tectonic history
     Late Paleozoic

      North America


         Appalachian                                                        Iberia
          orogenic
           activity;
          Uplift and
           erosion




                                                            Africa




 I conclude this talk by presenting the tectonic history of eastern North
 America. Iin the Late Paleozoic, Appalachian orogenic activity produced
 numerous contractional faults that later were reactivated, along with uplift and
 erosion.

 Figure modified from: Withjack, M.O., Schlische, R.W., and Olsen, P.E., 2005, Triassic-
 Jurassic rift basins of eastern North America," in Roberts, D.G., and Bally, A.W., eds.,
 Principles of Phanerozoic Regional Geology, Volume 1: New York, Elsevier, in press.




                                                                                            31
Tectonic history
     Late Triassic
                                             Slow rift-basin                 NW-SE
                                           subsidence in north              extension


       North America                                                      Iberia

         Rapid
       rift-basin
      subsidence
        in south



                                                          Africa
        NW-SE
       extension




 By Late Triassic time, rifting was occurring along the entire system, although
 subsidence was greater in the south than the north.

 Figure modified from: Withjack, M.O., Schlische, R.W., and Olsen, P.E., 2005, Triassic-
 Jurassic rift basins of eastern North America," in Roberts, D.G., and Bally, A.W., eds.,
 Principles of Phanerozoic Regional Geology, Volume 1: New York, Elsevier, in press.




                                                                                            32
Tectonic history
    latest Triassic/earliest Jurassic
                                  Continued subsidence
                                  in central and northern
       North America                     rift basins


                                                                          Iberia
              NW-SE
             extension

      Cessation of
      widespread
        rifting in
         south;
       uplift and
        erosion
                                                           Africa

          Focused extension in south




 At around the Triassic-Jurassic boundary, rifting ended in the south, and was
 replaced by uplift and erosion as focused extension occurred along the
 incipient seafloor spreading center. Rifting continued in the central and
 northern segments.

 Figure modified from: Withjack, M.O., Schlische, R.W., and Olsen, P.E., 2005, Triassic-
 Jurassic rift basins of eastern North America," in Roberts, D.G., and Bally, A.W., eds.,
 Principles of Phanerozoic Regional Geology, Volume 1: New York, Elsevier, in press.




                                                                                            33
Tectonic history
    earliest Jurassic (CAMP)
                                 Accelerated subsidence in central
       North America                  and northern rift basins

              NW-SE
             extension                                                       Iberia
       NW-SE
      shortening

                                                 Synrift lava flows fill central
                                                  and northern rift basins
                                       Dike & sill
                                      emplacement
      Postrift
        lava                                                     Africa
       flows         SDR's and incipient
                 seafloor spreading in south




 During earliest Jurassic CAMP magmatic activity, lava flows in the central
 and northern segment are synrift units, and diabase dikes indicate NW-SE
 extension. Accelerated subsidence occurred in these basins. Lava flows in the
 south are postrift units, and dikes indicate NW-SE shortening.Seaward-
 dipping reflectors (SDR’s) formed adjacent to the incipient seafloor spreading
 centers.

 Figure modified from: Withjack, M.O., Schlische, R.W., and Olsen, P.E., 2005, Triassic-
 Jurassic rift basins of eastern North America," in Roberts, D.G., and Bally, A.W., eds.,
 Principles of Phanerozoic Regional Geology, Volume 1: New York, Elsevier, in press.




                                                                                            34
Tectonic history
    Early to early Middle Jurassic
                                   Continued rift-basin                     NW-SE
                                   subsidence in north                     extension
      North America

               Cessation of
             rifting in central                                            Iberia
                  segment;
            uplift and erosion

                                       Formation of SDRs and incipient
        Ultra-slow                        seafoor-spreading centers
         seafloor                            in central segment
        spreading
         in south
                                                             Africa
                     ?



 From Early Jurassic to early Middle Jurassic time, ultra-slow seafloor
 spreading occurred in the south, rifting ended in the central segment, and
 rifting continued in the north. The central segment experienced uplift and
 erosion while SDR’s formed adjacent to incipient seafloor spreading centers.

 Figure modified from: Withjack, M.O., Schlische, R.W., and Olsen, P.E., 2005, Triassic-
 Jurassic rift basins of eastern North America," in Roberts, D.G., and Bally, A.W., eds.,
 Principles of Phanerozoic Regional Geology, Volume 1: New York, Elsevier, in press.




                                                                                            35
Tectonic history
    Middle Jurassic
                                          Continued                        NW-SE
                                      subsidence in north                 extension?
      North America

                   N-S
                shortening                                                   Iberia


        Seafloor
      spreading in
      southern and
         central
       segments
                                   Ridge
                                    jump                        Africa
                                  in south
                     ?



 The shortening direction during Middle Jurassic time was N-S to NNE-SSW.
 A ridge jump in the south was broadly coeval with the initiation of seafloor
 spreading in the central segment. The ridge jump produced the Blake Spur
 magnetic anomaly, which dies out at the transition from the southern segment
 to the central segment.

 Figure modified from: Withjack, M.O., Schlische, R.W., and Olsen, P.E., 2005, Triassic-
 Jurassic rift basins of eastern North America," in Roberts, D.G., and Bally, A.W., eds.,
 Principles of Phanerozoic Regional Geology, Volume 1: New York, Elsevier, in press.




                                                                                            36
Tectonic history
   Early Cretaceous
                                     Continued rifting in northern part
                                           of northern segment
                  Seafloor spreading in
                 southern part of northern
                        segment
      North America                                                      Iberia


                                                   +
                                               +
                                           +
                                       BSMA
                                       +
                                   +
                               +                                         Africa
                           +
                       +

                   ? ++



 In Early Cretaceous time, the end of rifting and the initiation of seafloor
 spreading in the northern segment was diachronous from south to north.

 Figure modified from: Withjack, M.O., Schlische, R.W., and Olsen, P.E., 2005, Triassic-
 Jurassic rift basins of eastern North America," in Roberts, D.G., and Bally, A.W., eds.,
 Principles of Phanerozoic Regional Geology, Volume 1: New York, Elsevier, in press.




                                                                                            37
Tectonic history
  late Early Cretaceous
                                                                      Seafloor
                                                                     spreading



     North America                                                        Iberia


                                                  +
                                              +
                                          +
                                      BSMA
                                      +
                                  +
                              +
                          +                                             Africa
                      +

                  ? ++



 By late Early Cretaceous time, seafloor spreading was underway along the
 entire system.

 Figure modified from: Withjack, M.O., Schlische, R.W., and Olsen, P.E., 2005, Triassic-
 Jurassic rift basins of eastern North America," in Roberts, D.G., and Bally, A.W., eds.,
 Principles of Phanerozoic Regional Geology, Volume 1: New York, Elsevier, in press.




                                                                                            38