HR: 1340h
AN: S43B-1005    [Abstracts]
TI: Seismic Imaging of Rifted Margins in the Southern Gulf of California
AU: * Paramo, P
EM: paramo@uwyo.edu
AF: University of Wyoming, Geology and Geophysics dept, Laramie, wy 82071 United States
AU: Holbrook, S W
EM: steveh@uwyo.edu
AF: University of Wyoming, Geology and Geophysics dept, Laramie, wy 82071 United States
AU: Brown, H E
EM: hbrown@uwyo.edu
AF: University of Wyoming, Geology and Geophysics dept, Laramie, wy 82071 United States
AU: Lizarralde, D
EM: danl@eas.gatech.edu
AF: Georgia Institute of Technology, School of Earth and Atms Sciences, Atlanta, GA 30332 United States
AU: Umhoefer, P
EM: paul.umhoefer@nau.edu
AF: Northern Arizona University, Dept of Geology, Flagstaff, AZ 86011 United States
AU: Kent, G
EM: gkent@uscd.edu
AF: Scripps Oceanographic Institution, 9500 Gilman Drive, La jolla, CA 92093 United States
AU: Harding, A
EM: aharding@ucsd.edu
AF: Scripps Oceanographic Institution, 9500 Gilman Drive, La jolla, CA 92093 United States
AU: Fletcher, J
EM: jfletche@cicese.mx
AF: CICESE, CICESE, Ensenada, BC 00000 Mexico
AU: Gonzalez, A
EM: mindundi@cicese.mx
AF: CICESE, CICESE, Ensenada, BC 00000 Mexico
AU: Axen, G
EM: gaxen@ess.ucla.edu
AF: UCLA, Dept of Earth and Space Sciences, Los Angeles, CA 90095 United States
AB: We present preliminary velocity models from two wide-angle seismic transects located in the southern Gulf of California along with coincident seismic reflection images. Continental rupture in the Gulf of California occurred recently and the conjugate margins can be studied with little uncertainty in plate reconstruction. Therefore it is considered an ideal place to analyze patterns of crustal extension and rift magmatism. The seismic reflection data were acquired with a 6-km-long streamer, 480-channel, aboard R/V Maurice Ewing, and ocean-bottom seismographs (OBSs) were deployed from R/V New Horizon. Onshore seismographs were also deployed along onshore extensions of the transects. Transect 5W runs northwest-southeast from the Los Cabos block, at the southern tip of the Baja California Peninsula, to the East Pacific Rise in the mouth of the Gulf. Transect 0E runs northeast-southwest from the hills of Sierra Madre in mainland Mexico near Mazatl n to approximately 115 km into the Gulf of California. Preliminary velocity models from Transect 5W margin show an abrupt transition from a 25-km-thick continental crust to an oceanic crust of normal thickness. Transect 0E crosses what is believed to be extended continental crust and lies in the initial direction of extension characteristic of the protogulf.
DE: 3000 MARINE GEOLOGY AND GEOPHYSICS
DE: 3025 Marine seismics (0935)
DE: 0900 EXPLORATION GEOPHYSICS
DE: 0935 Seismic methods (3025)
SC: Seismology [S]
MN: 2004 AGU Fall Meeting