2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM
Paper No. 206-7
Presentation Time: 3:20 PM-3:35 PM

Centennial-Millennial Scale Stability of a Large Gas-Hydrate Field in the Northern Gulf of Mexico: Investigating Linkages to Climate Change and Slope Erosion

INGRAM, Wesley C., Marine Sciences, University of North Carolina, Chapel HIll, Chapel Hill, NC 27516, wesley.ingram@dvn.com, MEYERS, Stephen, Geological Sciences, University of North Carolina - Chapel Hill, Mitchell Hall, 104 South Road, CB 3315, Chapel Hill, NC 27599, BRUNNER, Charlotte, Department of Marine Science, Univ of Southern Mississippi, Stennis Space Center, MS 39529, and MARTENS, Christopher, Marine Sciences, University of North Carolina, Chapel Hill, 3202 Venable Hall, Chapel Hill, NC 27516

Gas hydrates underlie a substantial portion of the Northern Gulf of Mexico margin. It has been proposed that such deposits are subject to catastrophic degassing events, resulting in slope destabilization, and the rapid release of methane into the ocean-atmosphere system. Although methane hydrates constitute a potential control on both climate change and slope sedimentation processes, many important questions remain about the stability of these deposits (e.g., their time scales of variability), and the precise factors that trigger large dissociation events. This study investigates centennial-millennial scale variability of an active gas-hydrate field in the northern Gulf of Mexico (Mississippi Canyon Federal Lease Block 118, or MC-118) during the late Pleistocene and Holocene. A depth transect of twelve sediment cores collected from sites above to below the field comprises a 20,000-year long record of slope sedimentation. A suite of sedimentologic, paleontologic, and geochemical data are used to evaluate (1) variable sedimentation across the study area, (2) the temporal stability of the gas hydrate deposits, and (3) their connection to recent paleoclimate and depositional events in the Gulf of Mexico. Elemental data obtained from X-ray fluorescence (XRF) scanning of the cores indicates pronounced changes in sedimentation across the study area. Contrasting deposition upslope and downslope of MC-118 provides a means to differentiate gas-hydrate induced erosion from regional slope erosion. Finally, analysis of Ba/Al, which has been previously proposed as a proxy for hydrate eruption events, suggests periods of enhanced hydrate dissociation over the past 20,000 years.

2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM
General Information for this Meeting
Session No. 206
Late Quaternary of the Northern Gulf of Mexico Margin: Climate Change, Sea-Level Change, and the Depositional Record
George R. Brown Convention Center: 320DE
1:30 PM-5:30 PM, Monday, 6 October 2008

Geological Society of America Abstracts with Programs, Vol. 40, No. 6, p. 278

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