Biostratigraphic correlation of eustatic cyclothems (basic Pennsylvanian sequence units) from Midcontinent to Texas and Illinois
- Univ. of Iowa, Iowa City (United States)
- Texas Tech Univ., Lubbock (United States)
- Kansas Geological Survey, Lawrence (United States)
- Illinois State Geological Survey, Champaign (United States)
The basic Midcontinent Pennsylvanian eustatic cyclothem (transgressive limestone, offshore shale, regressive limestone, nearshore/terrestrial shale/paleosol) has sequence stratigraphic counterparts (major eustatic cycles) in Texas and Illinois, in which the limestone members are poorly developed or localized because of proximity to detrital influx. The gray to black phosphatic facies of the offshore shales in all three areas, however, are characterized by abundant conodont faunas that not only are conspecific at each level across the entire region but also are diagnostic of individual cycles. These faunas, supplemented at several horizons by distinctive fusulinids and ammonoids, allow correlation of up to 16 of the major eustatic cycles at a time scale of about 400,000 years across a large area of North America. This correlation can be refined to perhaps 100,000 years when the intervening minor eustatic cycles are matched between the biostratigraphically diagnostic horizons. Similar successions of conodont faunas are reported in preliminary work on marine horizons in the Appalachians and in published work on the Russian platform augur well for eventual worldwide correlation of eustatic cycles on a time scale within the Milankovitch band of the Earth's orbital parameters during a period of time when glacial eustasy seems to have controlled inundation and withdrawal of the sea over large portions of the continents.
- OSTI ID:
- 5617627
- Report Number(s):
- CONF-910403-; CODEN: AABUD
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (United States), Vol. 75:3; Conference: Annual meeting of the American Association of Petroleum Geologists (AAPG), Dallas, TX (United States), 7-10 Apr 1991; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
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Sequence-stratigraphic implications of glacial-eustatic Pennsylvanian cyclothems in North America
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ILLINOIS
SEDIMENTARY BASINS
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BIOLOGICAL MARKERS
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AGE ESTIMATION
CARBONIFEROUS PERIOD
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CORRELATIONS
FOSSILS
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580000* - Geosciences