Depositional patterns and shelf-margin styles of a lowstand slope fan systems tract, offshore Louisiana

Conference · Tue May 01 04:00:00 EDT 1990 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:6857745

Bowen, B E ^[1]; Pacht, J ^[2]; Shaffer, B L.S.

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1. Geophysical Co., Houston, TX (USA)
2. RPI, Boulder, CO (USA)

A complete spectrum of facies from deep-water fans to up-dip deltaics and fluvial sediments occurs in the Pliocene-Pleistocene lowstand fan systems tracts of the Gulf of Mexico. Seismic data, well logs, and biostratigraphy have been used to delineate and map the upper Pliocene slope fan systems tract, commonly referred to as the Lenticulina I interval. This tract contains sands that are major hydrocarbon producers in the southern part of the Louisiana shelf. Both a ramp margin and a growth fault modified ramp margin can be recognized in this unit. Large submarine fans with well-developed channel levee complexes occur basinward of the growth fault margin. The sands in these sediments typically are thin-bedded and highly lenticular. On the upside of the growth faults, the slope fan sediments can be chronostratigraphically correlated to deltaics by using the encasing condensed sections that have been defined by biostratigraphy. The sands in the deltaics are coarsening-upward cycles, occasionally blocky, are generally thicker bedded than the downdip fan deposits. Updip, the semicontinuous to continuous reflectors of the deltaic sediments are replaced by highly discontinuous reflectors with variable amplitude characteristic of upper delta plain or fluvial deposits. A different set of facies is characteristic of the ramp margin. Extensive slope fan sediments are rarely developed and the updip deltaic wedge tends to be thicker and is characterized by slumping along the seaward margin. The deltaics occur in an area that extends about 100 mi along strike and 75 mi in the dip direction.

• OSTI ID: 6857745
• Report Number(s): CONF-900605--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Journal Volume: 74:5
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580000 -- Geosciences
ALLUVIAL DEPOSITS
ATLANTIC OCEAN
CARIBBEAN SEA
CENOZOIC ERA
DEPOSITION
FEDERAL REGION VI
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GULF OF MEXICO
LOUISIANA
NORTH AMERICA
OFFSHORE SITES
QUATERNARY PERIOD
SEAS
SURFACE WATERS
USA