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| Chronolgy of Events in the Geologic History of Virginia PAGE TWO - Youngest History. Read from bottom to top Go to Page One |
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| Age (mya) |
Events | Virginia Provinces | Observation/ Interpretation | Cross Section |
| UNCONFORMITY In progress. Creation of present topography and continued erosion. |
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| 65 - 0 Cenozoic |
REJUVENATION | BLUE RIDGE, VALLEY/RIDGE, ALLEGHENY PLATEAU | Gentle uplift; long resistant ridges, water gaps (trellis drainage). Dendritic drainage on Allegheny plateau | |
| UNCONFORMITY Most of Virginia eroded to peneplain by end of the Cretaceous |
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| 192 - 0 Cretaceous and Cenozoic |
CONTINENTAL MARGIN DEPOSITION | COASTAL PLAIN and CONTINENTAL SHELF | Eastward thickening wedge of marine and near shore sediments (often unconsolidated) | M |
| 230 - 192 Triassic/Lower Jurassic |
RIFTING and the opening of the Atlantic ocean | PIEDMONT and under the COASTAL PLAIN; Culpepper, Richmond, Farmville, etc. Basins | Rift graben clastics (border conglomerates, fluvial and lake) and mafic intrusive igneous rocks | L |
| EROSION AND UNCONFORMITY Allegheny mountains across most of Virginia undergoes erosion; extent of erosion unknown |
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| 320 - 230 Pennsylvanian and Permian |
ALLEGHENIAN OROGENY Gondwana (Africa) collides with eastern North America to create the supercontinent Pangaea. Final stage in closing of Protoatlantic (Wilson Cycle) |
ALLEGHENY PLATEAU | Molasse deposits (deltaic, shallow marine) spreading westward to Kansas | K |
| PIEDMONT, BLUE RIDGE, VALLEY AND RIDGE | Ramp and flat thrust faulting and folding | |||
| GOOCHLAND TERRANE | Plutonism (313 - 285 mya) metamorphism and deformation in eastern piedmont | |||
| 350 - 320 Mississippian |
OROGENIC CALM and final erosion of the Acadian mountains |
ALLEGHENY PLATEAU | Deposition of shelf carbonates (oolites, biosparites, etc.) in far western Virginia; clastics in SW Virginia and Pennsylvanaia | |
| UNCONFORMITY Acadian sourceland in eastern Virginia erodes; but no direct evidence. Remains in Avalon terrane |
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| 370 - 350 Mid/late Devonian |
ACADIAN OROGENY Avalon terrane extending from Virginia north to New England collides with east coast. Second stage in Wilson Cycle closing of the Protoatlantic (Rheic ocean) |
VALLEY AND RIDGE and under ALLEGHENY PLATEAU | Catskill clastic wedge deposiited in foreland basin of western Virginia and Pennsylvania and West Virginia | J |
| BLUE RIDGE | Fries-Rockfish valley fault activated; regional metamorphism | |||
| Avalon Terrane in Piedmont; Charlotte, Carolina state, and Goochland belt | Deformation, intrusion, volcanism, and metamorphism | |||
| 435 - 370 Silurian and Early Devonian |
OROGENIC CALM Central Appalachian Basin |
VALLEY AND RIDGE, ALLEGHENY PLATEAU | Blue Ridge/western Piedmont a low sourceland. To west a slowly subsiding basin of quartz sandstone, tidal and reef carbonates/evaporites. | I |
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| Last Update: 9/13/00 | |||