C sup 13 depleted authigenic carbonate buildups from hydrocarbon seeps, Louisiana Continental Slope

Conference · Fri Sep 01 04:00:00 EDT 1989 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:5113233

Roberts, H H; Sassen, R; Carney, R; Aharon, P ^[1]

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1. Louisiana State Univ., Baton Rouge (USA)

Geohazard and geochemical survey data consisting of high-resolution profiles, side-scan sonographs, drop cores, dredge samples, and borings have substantiated the consistent association between carbonate buildups and hydrocarbon seeps on the Louisiana continental slope. Analyses of lithified bottom samples indicate a range of carbonate mineralogies including aragonite, Mg-calcite, and dolomite that are extremely depleted in the C{sup 13} isotope ({delta}C{sup 13} values to {minus} 48 {per thousand} PDB). Microbial oxidation of methane (biogenic and thermogenic) and crude oil creates a source of pore-water CO{sub 2} containing isotopically light carbon which triggers carbonate precipitation. Geophysical and geochemical evidence suggests that both surface and subsurface lithification is taking place. Recent observations and samples collected using a Pisces class research submersible confirm the abundance of C{sup 13} depleted sedimentary carbonates and massive authigenic buildups associated with the tops and flanks of shallow salt diapirs and gas hydrate hills.

• OSTI ID: 5113233
• Report Number(s): CONF-8910221--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Journal Volume: 73:9
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
ALKANES
CARBON 13
CARBON ISOTOPES
CARBONATE ROCKS
CHEMICAL REACTIONS
EVEN-ODD NUCLEI
EXPLORATION
FEDERAL REGION VI
GEOLOGIC DEPOSITS
GULF COAST
HYDROCARBONS
ISOTOPES
LIGHT NUCLEI
LOUISIANA
METHANE
MINERAL RESOURCES
NATURAL GAS DEPOSITS
NORTH AMERICA
NUCLEI
OFFSHORE SITES
ORGANIC COMPOUNDS
OXIDATION
PETROLEUM DEPOSITS
RESOURCES
ROCKS
SALT DEPOSITS
SEDIMENTARY ROCKS
STABLE ISOTOPES
USA