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					 Golden Gate NRA
Geology of National Parks




                            1
Regional
  Map




      2
Golden Gate
   NRA




          3
Relief Map of Golden Gate Region




• Modified from map by Norm Maher, USGS
                                          4
Ocean-Continent Subduction




                             5
Marin Headlands Terrane
       Migration
            • The Marin Headlands
              has migrated from the
              Pacific Ocean to form
              rocky outcrops on
              both sides of the
              Golden Gate Bridge,
              over a 200 million
              year period


                                      6
               Marin Headlands




• (Left) Red spot shows location of Marin Headlands Terrane
  200 million years ago
• (Right) 150 million years ago
                                                              7
        Marin Headlands Docking




• (Left) 100 million years ago
• (Right) Docking occurred about 70 million years ago
                                                        8
        Marin Headlands Today




• (Left) 40 million years ago
• (Right) Today – north and south of the Golden Gate   9
           Point Bonita




• Black basalt forms the point   10
Pillow Basalts at Point Bonita




                                 11
  Formation of
   Pillows off
     Hawaii

• Photo: Gordon
  Tribble, USGS




                  12
Hydrothermal
  Veins in
“Greenstone”
• The greenstone is
  metamorphosed pillow
  basalt




                    13
Black Smoker Off Hawaii




                          14
Electron Microscope Image of
         Radiolarian




                               15
Ribbon Chert, Marin Headlands




                                16
Jasper




         17
   Muddy
 Sandstones
• Geologist Jim
  Locke examining
  rocks at the base of
  the Tiburon
  Peninsula




                     18
     Isoclinal
     Folding
• Severe tectonic
  deformation in the
  muddy sandstones at
  the base of the
  Tiburon Peninsula




                        19
   Turbidity Current




• Photo by William Dillon,
  Research Geologist, USGS   20
Graded Bedding in Spherical
        Concretion




                              21
Serpentine-Melange Contact




                             22
Melange
Spring
• Water drains from
  the melange unit,
  located at the slide
  near the bend of
  the cul-de-sac in
  the previous slide




                 23
Blueschist




             24
Blueschist Rock




                  25
          Serpentinite Layers




Sheet-like outcroppings of serpentinite on Ring Mountain
                                                           26
           Serpentinite Outcrop




• Serpentinite forms part of the Franciscan Complex on the
  coastal bluffs at the south end of the Golden Gate Bridge
                                                          27
Tiburon Mariposa Lily




                        28
Burdel Mountain




                  29

				
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