Importance of shelf to trough black phosphatic shales in Mid-Continent
Pennsylvanian black shales containing radiolarian-rich phosphatic nodules, such as are now accumulating on outer shelves and upper slopes of modern tropical seas, are widespread throughout much of Kansas, Oklahoma, and other Mid-Continent states. Conodonts, inarticulate brachiopods, conularids, fish teeth, and radiolarians constitute the main biota of these black shales. Such shales characterize about half the 60 or more known Pennsylvanian cyclothems of Oklahoma and Kansas. These shales, individually approximating about 1 m (3 ft) in thickness in the extensively mined limestone and coal sequences of eastern Kansas and northeastern Oklahoma, have been described by Moore, Branson, Heckel, and others. However, much thicker, up to 8 m (26 ft), coeval zones in the deep Arkoma and Anadarko basins are surprisingly under-reported considering that such highly organic shales may have been the prime source of commercial oil and gas. Dysaerobic (low oxygen) and supposedly slightly shallower water, dark gray concretionary shales adjoin these black phosphatic shales. In many cyclothems the dysaerobic facies represent the deep stillstand facies where the latter in missing. Typically, it features a middle to outer shelf diverse molluscan community, including rapidly evolving goniatites useful for correlations. These deep-water stillstand indicators are more useful for regional correlations than those for the low water stillstand that include coals, coaly shales, red beds, and paleosols. Carboniferous sea level fluctuations at times probably exceeded 200 m (656 ft), arising from interacting tectonic pulses and glacial-eustatic changes.
- OSTI ID:
- 6156033
- Report Number(s):
- CONF-8304200-
- Journal Information:
- Am. Assoc. Pet. Geol., Bull.; (United States), Vol. 67:3; Conference: Annual AAPG/SEPM/EMD/DPA convention, Dallas, TX, USA, 17 Apr 1983
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BLACK SHALES
GEOLOGY
FEDERAL REGION VII
RESOURCE POTENTIAL
SOURCE ROCKS
BITUMINOUS MATERIALS
CARBONACEOUS MATERIALS
CHATTANOOGA FORMATION
ENERGY SOURCES
FOSSIL FUELS
FUELS
GEOLOGIC FORMATIONS
MATERIALS
NORTH AMERICA
OIL SHALES
USA
040201* - Oil Shales & Tar Sands- Site Geology- (-1989)