HR: 0800h
AN: NS51B-01    [Abstracts]
TI: The Presence of Gas Hydrate Layers Inferred From BSR at the West Margin of the Baja Californian Peninsula
AU: * Cruz-Melo, C E
EM: cmelo_mx@yahoo.com.mx
AF: Universidad Nacional Autónoma de México, Insituto de Geofsica, Coyoacan, DF 04510, Mexico
AU: Mortera-Gutierrez, C A
EM: cmortera@geofisica.unam.mx
AF: Universidad Nacional Autónoma de México, Insituto de Geofsica, Coyoacan, DF 04510, Mexico
AU: Bandy, W L
EM: bandy@geofisica.unam.mx
AF: Universidad Nacional Autónoma de México, Insituto de Geofsica, Coyoacan, DF 04510, Mexico
AU: Michaud, F
EM: micho@obs-vlfr.fr
AF: Université Pierre-et-Marie-Curie, Géosciences Azur Université Pierre-et-Marie-Curie, Villefranche-sur-Mer, France
AU: Ortega-Ramirez, J
AF: Instituto Nacional de Antropología e Historia, Laboratorio de Geofísica, INAH, Cuauhtemoc, DF , Mexico
AU: Bourgois, J
AF: IRD & CNRS, Université Pierre-et-Marie-Curie, Paris, France
AU: Royer, J
AF: CNRS, CNRS, Plouzané, France
AB: Studies of hydrate occurrence have been very limited at the Mexican Pacific margins. Five seismic reflection profiles across the west margin of the Baja California Peninsula were examined to determine the temperature and pressure at sediment layers containing gas hydrate, inferred from the presence of BSR events. During March and April, 2002, a French-Mexican marine geophysical expedition (FAMEX-2002) was carried out in the Eastern Pacific margin to survey the sea floor structures in the Mexican region near the peninsula [22N-29N]. More than 4,000 nautical miles of seismic reflection sections were gathered during FAMEX-2002. BSR were well identified at several seismic reflection profiles across the peninsula western slope [26N and 23.5N], at depths greater than 3,000 m bsl. The maximum length of BSR seen in the margin is greater than 30 km long. Using phase diagrams of the hydrate stability zones and range of temperatures measured at the sea floor, we were able to estimate interactively the upper and bottom limits of the BSR temperatures to preserve the hydrate state at depths greater than 3,200 m bsl and 200 m bsf.
DE: 1050 Marine geochemistry (4835, 4845, 4850)
DE: 3004 Gas and hydrate systems
DE: 4219 Continental shelf and slope processes (3002)
SC: Near-Surface Geophysics [NS]
MN: 2007 Joint Assembly