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What are the three orogenies?
Taconic
Acadian
Alleghanian
What is an orogeny?
mountain building event
(1) What occurred during the Proterozoic (Before Cambrian)?
Rifting of Rodinia
rifting of crystalline basement
Grenville orogeny - assembly of Rodinia
NA part left of Rodinia was called Laurentia
(2) What happened during the Cambrian - Early Ordovician?
Eastern Laurentia = Passive Margin
warm, shallow marine environment here → carbonate deposits
deposit area later becomes GREAT VALLEY
(3) What happens during the Later Ordovician - Silurian?
TACONIC OROGENY
Eastern Laurentia = Active Margin
begins subducting under Gondwanan plate
Taconic Island Arc (TIA) - caused by hydrous melting in the mentle
TACONIC OROGENY - TIA collides w/ Laurentia → foreland basin produces downwarping and packets of sediment
some TIA left on Laurentia plate to make Piedmont
(4) What happened during the Middle Devonian - Middle Mississippian?
ACADIAN OROGENY
Avalonia (micro-continent) collides w/ Laurentia → new foreland basin & sedimentary packets ON INLAND SIDE
some of Avalonia is sutured onto TIA & Laurentia
(5) What happened during the Pennsylvanian - Permian?
ALLEGHANIAN OROGENY
Gondwana collides w/ Laurentia
continental v. continental
Twice as long as Taconic & Acadian Orogenies
Intense mountain building & formation of plateau
This orogeny COMPLETED assembly of Pangea
intense collision produced plateau & thrust faults
(6) What happened to Modern Day After Breakup?
intense thrust faulting
Appalachian mtns => SEVERELY ERODED

What is missing from this figure?
Appalachian Plateaus

What is missing from this figure?
Appalachian Front

What is missing from this figure?
Valley & Ridge

What is missing from this figure?
North American Thrust

What is missing from this figure?
Blue Ridge

What is missing from this figure?
Piedmont

What is missing from this figure?
Coastal Plain
What is exposed of particular interest in the Blue Ridge?
crystalline basement
Expand on the Piedmont.
mostly sutured igeneous terrain from TIA and Avalonia - Africa material below coastal plain