HR: 0830h
AN: OS51B-0853    [PDF]
TI: Seafloor methane discharge at the Guaymas Transform, Gulf of California: New insights from seismic reflection, thermal, and ROV data
AU: * Nealon, J W
EM: mhornbac@uwyo.edu
AF: University of Wyoming, Department of Geology and Geophysics, Laramie, Wy 82072 United States
AU: Holbrook, W S
EM: steveh@uwyo.edu
AF: University of Wyoming, Department of Geology and Geophysics, Laramie, Wy 82072 United States
AU: Paull, C K
AF: Monterey Bay Aquarium Research Institute, 886 Cannery Row, Moss Landing, CA 95039 United States
AU: Peltzer, E T
AF: Monterey Bay Aquarium Research Institute, 886 Cannery Row, Moss Landing, CA 95039 United States
AU: Ussler, W
AF: Monterey Bay Aquarium Research Institute, 886 Cannery Row, Moss Landing, CA 95039 United States
AB: We combine seismic reflection profiling, thermal gradient data, and ROV observations to examine active venting associated with the methane hydrate system in the Guaymas Transform, Gulf of California. In comparison to the 13 degrees C/km regional average, thermal gradients at the vent site are locally elevated in both measured values (584 C/km) and values calculated from BSR depths (321 C/km). Corresponding with the locally elevated thermal gradient is an abrupt shallowing of the BSR beneath the vent, which suggests a strong link between advective heat flow, vent activity, and hydrate stability zone thickness. A well-developed chemosynthetic biological communities was found surrounding the vent, and similar communities elsewhere along the transform ridge indicate that methane has recently escaped to the seafloor in multiple locations. There is little evidence of other BSR anomalies at these locations indicating that the seeps that supplied methane to these areas were either "cold" or that the local advective heat transport in this system is highly transient and the base of hydrate stability is able to respond to the changes in temperature over time scales of years.
DE: 3000 MARINE GEOLOGY AND GEOPHYSICS
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting