Post on 30-Dec-2015
transcript
Earth History GEOL 2110
The Paleozoic EraCarboniferous and the Permian Periods
in North America
Major Concepts
• Carbonate deposition dominant in the Silurian and Devonian, persisted into the early Carboniferous (the Mississippian period).
• After a major regression and subsequent transgression marking the Mississippian-Pennsylvanian break in North America, the Absaroka sequence was dominated by clastic sediments and great accumulations of land-based organic material creating coal seams.
• This change in sedimentation, which persisted into the Permian, was triggered by creation of the final orogenic event of the Appalachian mobile belt caused by the collision of southeastern North America with Africa and South America and the creation of the largest continental land mass ever on Earth - Pangea
Events of the Late Paleozoic Era
Mississippian DepositsMore Limestone
Madison LS, MT
Redwall LS, AZPahasapa LS, SD
ChockfulO’ Crinoids
Late Mississippian Regression
Immature clastic sediment appear in Eastern NA depositsSourced from deeper erosion of rejuvenated Caledonian and Acadian Mts
More Unconformities developed on warped craton highs
Pennsylvanian DepositsClastic Sedimentation Dominates (+Coal)
Pennsylvanian DepositsCyclothems – Trangressive Cycles
TRAN
SGRE
SSIO
N
Sandstone -Delta / Barrier Island
Shale – Lagoon / Floodplain
Organic Shale
Coal
Limestone - Marine
Illinois Basin Cyclothem
Forested Marsh/Swamp
Sea Regression
Land Trangression
Sea Trangression
Pennsylvanian DepositsCyclothems – Trangressive Cycles
Land Transgression Sea Transgression
Pennsylvanian DepositsOver 100 Cycles in 100 million years!
Cause of Cycles-Rapid sea level changes due to Gondwanaland glaciation- Spasmodic tectonic up-down oscillations-Cyclic climate change affecting erosion and sedimentation
Pennsylvanian Coal DepositsSubtropical Rain Forests
Peat
Anthracite
Everglades Bituminous Coal
AnthraciteCoal
Permian Deposits Craton Tilts West / Seas Retreat / Climate Dries
Barrier Reefs in the Southwest
Ancestral Rocky MountainPennsylvanian-Permian Uplift
Late Paleozoic Strata of the Grand Canyon
KlsTf
Css
HSh
Sgp
Late Paleozoic Strata of the Sedona Area
Permian Climate Dries In the Rain Shadow of the Appalachians
The Appalachian Orogeny
Creating Pangea ~250 Ma
Continent-Continent CollisionMonster Thrust Faulting
~260 Km Displacement
1950’s Interpretation
1980
Summary of Paleozoic Tectonics
North American Paleozoic Orogenies
Acadian/Caledonian
Appalachian/Hercynian
Taconian
Gondwanaland
Next Lecture
The Paleozoic EraGeological History of Gondwanaland and Late
Paleozoic Life
Mid-term on Friday!!Chapters 8-13