Geochemical constraints on the distribution of gas hydrates in the Gulf of Mexico

Gas hydrates are common within near-seafloor sediments immediately surrounding fluid and gas venting sites on the continental slope of the northern Gulf of Mexico. However, the distribution of gas hydrates within sediments away from the vents is poorly documented, yet critical for gas hydrate assessments. Porewater chloride and sulfate concentrations, hydrocarbon gas compositions, and geothermal gradients obtained during a porewater geochemical survey of the northern Gulf of Mexico suggest that the lack of bottom simulating reflectors in gas-rich areas of the gulf may be the consequence of elevated porewater salinity, geothermal gradients, and microbial gas compositions in sediments away from fault conduits.

[1]  W. Reeburgh.  AN IMPROVED INTERSTITIAL WATER SAMPLER1 , 1967 .

[2]  G. Redden,et al.  Hydrocarbon gas in sediment from the shelf, slope, and basin of the Bering Sea , 1980 .

[3]  Paul J. Wallace,et al.  Proceedings of the Ocean Drilling Program, 164 Initial Reports , 1996 .

[4]  W. Reeburgh,et al.  METHANE CONSUMPTION IN CARIACO TRENCH WATERS AND SEDIMENTS , 1976 .

[5]  W. Borowski,et al.  Marine pore-water sulfate profiles indicate in situ methane flux from underlying gas hydrate , 1996 .

[6]  Alexei V. Milkov,et al.  Estimate of gas hydrate resource, northwestern Gulf of Mexico continental slope , 2001 .

[7]  J. Brooks,et al.  Light hydrocarbons in recent Texas continental shelf and slope sediments , 1978 .

[8]  Alexei V. Milkov,et al.  Preliminary assessment of resources and economic potential of individual gas hydrate accumulations in the Gulf of Mexico continental slope , 2003 .

[9]  Carolyn A. Koh,et al.  Clathrate hydrates of natural gases , 1990 .

[10]  I. MacDonald,et al.  Gas hydrate and chemosynthetic biota in mounded bathymetry at mid-slope hydrocarbon seeps: Northern Gulf of Mexico , 2003 .

[11]  P. Hart,et al.  High-resolution seismic-reflection investigation of the northern Gulf of Mexico gas-hydrate-stability zone , 2002 .

[12]  W. Borowski,et al.  Global and local variations of interstitial sulfate gradients in deep-water, continental margin sediments: Sensitivity to underlying methane and gas hydrates , 1999 .

[13]  Alexei V. Milkov,et al.  Thickness of the gas hydrate stability zone, Gulf of Mexico continental slope , 2000 .

[14]  H. Roberts,et al.  Submarine venting of brines in the deep Gulf of Mexico: Observations and geochemistry , 1992 .

[15]  J. Brooks,et al.  Organic geochemistry of sediments from chemosynthetic communities, Gulf of Mexico slope , 1994 .