The Geology of Virginia

Time (Ma) Eon Era  Period Epoch Events
0.011 P
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Quaternary Holocene Chesapeake Bay forms
1.8 Pleistocene Dramatic climate oscillations, Rise & fall of sea-level cutting scarps along major rivers
5.0 Tertiary  Pliocene Marine sedimentation in Yorktown Fm.
23 Miocene Chesapeake group, erosional interval

38

Oligocene erosional interval
54 Eocene Chesapeake Bay Impact Structure
65 Paleocene erosional interval
146 Meso-
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Cretaceous Shallow sea covers eastern Virginia
208 Jurassic Atlantic Ocean opens, East flowing rivers (James, Roanoke, etc.) develop
245 Triassic Atlantic rifting begins- Deposition of sediments in rift-basins
286

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Permian ALLEGHANIAN OROGENY- Alleghanian mountain building due to continental collision (P, BR, & V&R)
325 Pennsylvanian Coals deposited in coastal swamps (AP), Alleghanian orogeny begins (Petersburg granite emplaced- Piedmont)
360 Mississippian Passive margin sedimentation in V&R
410 Devonian ACADIAN OROGENY- Sediment shed from Acadian mountains deposited in Valley & Ridge
440 Silurian Taconic highlands eroded development of west-facing passive margin
505 Ordovician TACONIC OROGENY- affects rocks of the Piedmont, BR, & V&R
544 Cambrian Carbonate deposition on passive margin (V&R)
650 P
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Neoproterozoic 600-550: Late phase of Iapetan rifting (Catoctin basalts extruded)
   
900 750-700: Early phase of Iapetan rifting ( Mt. Rogers volcanics, Mechum River sediments)
 

Mesoproterozoic

1100-950: GRENVILLIAN OROGENY
   
1600  
 

Paleoproterozoic


 
   
2500  
 




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3800 Atmosphere develops
 



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4500 Formation of the Earth and cooling of the crust
 

(11/20/99) Virginia Geology William and Mary Geology Home Page