Earth History GEOL 2110

The Paleozoic EraPart 5a: Stratigraphy and Tectonics of the

Carboniferous and the Permian Periodsin 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 large 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

Shale

Organic ShaleCoal

Limestone

Illinois Basin Cyclothem

Pennsylvanian DepositsCyclothems – Trangressive Cycles

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 EraPart 5b: Geological History of Gondwanaland

and Late Paleozoic Life

Mid-term on Friday!!Chapters 8-13