Chapter 11 – Late Paleozoic Events. 160 million years Three periods Devonian Mississippian Pennsylvanian Permian By the end of the Permian, Pangaea was completely assembled from the six plates that fled Rodina. The Seas Come In, The Seas Go Out.
160 million years
By the end of the Permian, Pangaea was completely assembled from the six plates that fled Rodina
The end of the Early Paleozoic had much of North America above sea level and eroding.
At the beginning of the Late Paleozoic the seas were advancing again depositing sediment over the old unconformity.
As sea level rose the Oriskany Sandstone of New York, Pennsylvania, Virginia, and West Virginia are deposited. Important glass sand.
South of New York
Contains tourmaline, zircon, and rutile and lacks fast weathering minerals. Reworked.
Contains less resistant minerals
Pyroxenes, hornblende, and biotite
Derived from igneous or metamorphic minerals; not re-worked sedimentary rocks.
Chattanooga Shale composed of silts and clays from erosion of Acadian highlands.
Contains no fossils, but does contain pyrite and disseminated carbon indicating deposition in stagnant, oxygen-poor water.
Later a thick deposit of limestones are deposited.
Last great Paleozoic flooding of North America
South Dakota and Montana to Canada
Arid climate reef-enclosed basins. Rock gypsum
Petroleum in reef limestones
Important Canadian oil source
Utah and Colorado
Flooded by Absaroka Sea
Thick beds of halite, gypsum and anhydrite (waterless gypsum)
Assembly of Pangaea
Baltica collides with N.A. to form northern Appalachian Mtns.
Avalon microcontinent collides with volcanic arc and then NW Africa to form the southern Appalachian Mtns.
The tall, ancestral Appalachian Mtn’s are shedding sediments west (Catskill Clastic Wedge) and east (Devonian Old Red Sandstone).
Important natural gas deposits in sandstones/shales.