Mississippian and Pennsylvanian (Carboniferous) Notes

Mississippian and Pennsylvanian (Carboniferous)

Carboniferous Period

  • The Carboniferous period includes both the Mississippian and Pennsylvanian subperiods.
  • The Carboniferous was named by Conybeare and Phillips in 1822, marking it as the first modern system.
  • The name "Carboniferous" means “coal-bearing,” originating from the extensive coal seams found in England.
  • In North America, the Carboniferous is divided into the Mississippian (mainly marine rocks) and Pennsylvanian (more terrestrial rocks with coal) subperiods. Globally, these are considered subperiods of the Carboniferous.

Carboniferous Subdivisions

The Carboniferous System is divided into subsystems and ages, with corresponding stages. Here's a simplified view:

  • Permian
    • Cisuralian
      • Asselian (younger)
  • Pennsylvanian
    • Gzhelian (298.9-303.7 Ma)
    • Kasimovian (303.7-307.0 Ma)
    • Moscovian (307.0-315.2 Ma)
    • Bashkirian (315.2-323.2 Ma)
  • Mississippian
    • Serpukhovian (323.2-330.9 Ma)
    • Viséan (330.9-346.7 Ma)
    • Tournaisian (346.7-358.9 Ma)
  • Devonian
    • Late
      • Famennian (older)

Regional Subdivisions

The Carboniferous also has regional subdivisions across different areas:

  • Russian
    • Gzhelian
    • Kasimovian
    • Moscovian
    • Bashkirian
    • Serpukhovian
    • Visean
    • Tournaisian
  • Western European
    • Rotliegend
    • Silesian
    • Dinantian
    • Autunian
  • North American
    • Virgilian
    • Missourian
    • Desmoinesian
    • Atokan
    • Morrowan
    • Chesterian
    • Meramecian
    • Osagean
    • Kinderhookian
    • Chautauquan
  • Chinese
    • Zisongian
    • Xiaoyaoan
    • Mapingian
    • Daiaan
    • Weiningian
    • Huashibanian
    • Luosuan
    • Dewuan
    • Shangsian
    • Tatangian
    • Jiusian
    • Aikuanian
    • Tangbagouan
    • Gelaohean

Carboniferous Paleogeography

Middle Mississippian (340 Ma)

  • Gondwana was located at the South Pole, mainly in the southern hemisphere.
  • Glaciation occurred in Gondwana during the Late Paleozoic Ice Age.
  • Euramerica was situated across the equator, experiencing high sea levels until the late Mississippian (end of the Kaskaskia sequence).
  • Warm, shallow seas were prevalent.

Late Pennsylvanian (300 Ma)

  • Gondwana remained over the South Pole and heavily glaciated during the Late Paleozoic Ice Age.
  • Gondwana moved northward throughout the late Paleozoic, leading to a collision with Euramerica.
  • This collision contributed to the formation of Pangea.
  • Siberia and Euramerica collided, forming Eurasia (Laurussia) in the late Carboniferous/Permian period.

Orogenies

Antler Orogeny

  • Continued into the Carboniferous period.
  • Erosion of the Antler highlands resulted in the deposition of sediments (2 km of sandstone, shale, lavas, ash beds) adjacent to the mountains.
  • These deposits are now exposed in Nevada and the Klamath Mountains of Northern California.

Alleghanian Orogeny

  • A series of collisions occurred during the late Pennsylvanian-Permian period.
  • Northwestern Gondwana collided with southeastern Laurentia.
  • This collision initiated the formation of Pangea.
  • The mountain belts formed include the Appalachian, Ouachita, Arbuckle/Wichita, and Uncompahgre ranges.
  • These belts stretch 1600 km from southern New York to central Alabama.

Tectonic Events and Supercontinent Formation

  • Late Silurian (~420 million years ago):
    • North American Plate interacting with the Taconic Terrane in the western Iapetus Ocean.
    • Avalonia Island Arc present.
  • Late Devonian (~370 million years ago):
    • Avalon Terrane (New England) approaching the Proto-African Plate (Gondwanaland).
    • Formation of the Catskill Delta.
  • Late Mississippian (~320 million years ago):
    • Early stages of the Alleghenian Orogeny.
    • Formation of the supercontinent Pangaea began.
  • Late Pennsylvanian (~290 million years ago):
    • Climax of the Alleghenian Orogeny.
    • Fold belt forms.
    • Development of "Sedimentary Appalachians" (The Appalachian Basin).
  • Late Permian (~250 million years ago):
    • The supercontinent Pangaea is fully formed.
    • Erosion of relief.

Sea Level Changes

  • Kaskaskia-Absaroka transition around the Mississippian-Pennsylvanian boundary.
  • Cyclothems, which are cyclic repetitions of marine and nonmarine strata, occurred.
  • These were due to repeated transgressions and regressions caused by glacial and interglacial periods.
  • Cyclothems are characteristic of Pennsylvanian rocks and some Permian rocks.
  • They are crucial for correlating rocks and understanding the Late Paleozoic Ice Age.

Cyclothem Facies

  • West Texas (Midland Basin): Deep marine deposition occurred continuously.
  • Midcontinent (Kansas): A major cyclothem sequence is observed with a general westward progradation of the shoreline during major regressions.
  • Illinois Cyclothem: Coal beds represent the marine highstand deposit where marine strata is absent.
  • Appalachian Cycles: All cyclothems are bounded by exposure surfaces with paleosols.

Carboniferous Coal Formation

  • Low-lying, warm, swampy areas provided ideal conditions for coal swamps.
  • Carboniferous trees were large and sturdy, containing abundant bark and lignin-enforced tissues.
  • Lignin was undigestible by existing fungi, preventing decomposition after death.
  • Carbon from these trees was buried in low-oxygen swamps and transformed into coal.
  • The burial of carbon led to the removal of atmospheric CO_2, promoting cooling and a rise in atmospheric oxygen levels.

Atmospheric Changes and Terrestrialization

  • Increase in atmospheric oxygen and terrestrialization of land occurred during the Carboniferous period.
  • The Carboniferous atmosphere contained approximately 35% oxygen.
  • This high oxygen level facilitated the evolution of giant arthropods, such as the 28-inch wingspan Meganeura and the 8.5 ft Arthropleura.