Seismic stratigraphic framework of Louisiana Continental Margin: clues to hydrocarbon sourcing

Conference · Mon Sep 01 04:00:00 EDT 1986 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:6932000

Dinkelman, M G

Interpretation of several thousand miles of multichannel seismic data indicates that large volumes of continental rise and basinal sediments have been continuously entrapped and are overridden by the basinward flow or creep of broad, extensive salt tongues that form the lower slope and Sigsbee Escarpment. Thick accumulations of Lower Cretaceous to upper Miocene sediments are identified beneath the salt at least 60 km landward of the escarpment. Spotty seismic data suggest that the Cretaceous to middle Miocene succession extends up to 120 km landward of the escarpment and beneath the present shelf break. Pleistocene-Holocene sequences of the deep gulf can be traced up to 15 km landward of the escarpment, where they are truncated by the base of the salt. Similar truncation of older deep gulf sequences by salt occurs progressively farther landward of the escarpment. Recently, the case has been made that hydrocarbons found in seeps and reservoirs on the outer shelf and upper slope are generated from Miocene anoxic basins buried at depth. Anoxic slope basins are presently rare, and their total sediment volume is small. It is unlikely that these anoxic basins were significantly more numerous during the Miocene or that their sediment volume was significantly greater. Therefore, the scenario of large allochthonous salt tongues, or flows, overriding flat continental rise and basinal sediments high in organics suggests that: (1) much of the hydrocarbon found in shallow Pliocene-Pleistocene reservoirs along the shelf and upper slope may have been generated from the now deeply buried Cretaceous to early Tertiary marine sedimentary sequences since the late Miocene-early Pliocene, and (2) hydrocarbons migrated vertically upward relatively recently along postsedimentary faults that cut the decollement.

• Research Organization: ARCO Exploration and Technology Co., Plano, TX
• OSTI ID: 6932000
• Report Number(s): CONF-8610199-
• Conference Information: Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 70:9
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
ATLANTIC OCEAN
CARIBBEAN SEA
CENOZOIC ERA
CONTINENTAL MARGIN
CRETACEOUS PERIOD
FEDERAL REGION VI
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GULF OF MEXICO
LOUISIANA
MESOZOIC ERA
MINERAL RESOURCES
NATURAL GAS DEPOSITS
NORTH AMERICA
PETROLEUM DEPOSITS
RESOURCES
SEAS
SOURCE ROCKS
SURFACE WATERS
TERTIARY PERIOD
USA