Structure, stratigraphy, and depositional environment of the heterostegina limestone and overlying sandstones in the Lake Pontchartrain area of southeast Louisiana
Conference
·
OSTI ID:45240
- Univ. of Southwestern Louisiana, Lafayette, LA (United States)
The Heterostegina zone of the Oligocene Anahuac Formation in southwestern Louisiana occurs in the subsurface as an extensive shelf reef complex. The Heterostegina limestone is overlain by strata associated with the Oligocene Discorbis and lower Miocene Robulus (43) biostratigraphic zones. Examination of electric logs and drill cuttings from wells in the Lake Pontchartrain area of southeastern Louisiana reveals the importance of the Heterostegina reef as a paleoenvironmental punctuation marking a significant shift in regional depositional patterns that occurred between the generally transgressive Oligocene seas and the generally regressive Miocene seas. Fauna identified in thin section from the Heterostegina reef interval suggest deposition in a warm, shallow-marine environment relatively free of significant clastic influx. An eastward migration of late Oligocene-early Miocene stream systems introduced an influx of clastic sediments onto the ancient shelf of the Lake Pontchartrain area, which influenced the termination of favorable conditions for Heterostegina reef growth. Lithofacies I is characterized by thick, shore-parallel sandstone deposits and is interpreted to have been deposited in association with a barrier-beach/tidal-inlet channel environment. Lithofacies II is characterized by shale-prone sandstone intervals, which are immediately overlain by calcareous mudstones and limestones deposited in the offshore inner-middle neritic environment. Five oil and gas fields in the study area have produced hydrocarbons from the interval of interest. The occurrence of hydrocarbons at these locations with respect to mechanisms of entrapment and areal extent of the reservoirs was characterized through detailed subsurface mapping.
- OSTI ID:
- 45240
- Report Number(s):
- CONF-941065--
- Country of Publication:
- United States
- Language:
- English
Similar Records
Structure, stratigraphy, and depositional environment of the Heterostegina limestone and overlying sands in the Lake Pontchartrain Area of southeast Louisiana
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Journal Article
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Thu Sep 01 00:00:00 EDT 1994
· AAPG Bulletin
·
OSTI ID:96269
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Conference
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Tue Dec 31 23:00:00 EST 1991
· Geological Society of America, Abstracts with Programs; (United States)
·
OSTI ID:5755331
Heterostegina zone carbonates, southeastern Louisiana-offshore Mississippi: Petrography, seismic stratigraphy, hydrocarbon potential
Conference
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Wed Sep 01 00:00:00 EDT 1993
· AAPG Bulletin (American Association of Petroleum Geologists); (United States)
·
OSTI ID:6850637