HR: 1340h
AN: T43B-1411    [Abstracts]
TI: Crustal Structure of the Southern Gulf of California, the East Pacific Rise to the Jalisco Block
AU: * Brown, H E
EM: hbrown@uwyo.edu
AF: University of Wyoming, 1000 University Ave, Laramie, WY 82071 United States
AU: Paramo, P
EM: paramo@uwyo.edu
AF: University of Wyoming, 1000 University Ave, Laramie, WY 82071 United States
AU: Holbrook, W S
EM: steveh@uwyo.edu
AF: University of Wyoming, 1000 University Ave, Laramie, WY 82071 United States
AU: Lizarralde, D
EM: danl@whoi.edu
AF: Woods Hole Ocng. Institute, MS 22, Woods Hole, MA 02543 United States
AU: Kent, G
EM: gkent@ucsd.edu
AF: Scripps Institute of Oceanography, IGPP, La Jolla, CA 92037 United States
AU: Harding, A
EM: aharding@ucsd.edu
AF: Scripps Institute of Oceanography, IGPP, La Jolla, CA 92037 United States
AU: Gonzalez, A
EM: mindundi@cicese.mx
AF: CICESE, Dept. of Geology, Ensenada, BA 22860 Mexico
AU: Fletcher, J
EM: jfletche@cicese.mx
AF: CICESE, Dept. of Geology, Ensenada, BA 22860 Mexico
AU: Umhoefer, P
EM: paul.umhoefer@nau.edu
AF: Northern Arizona University, Dept. of Geology, Flagstaff, AZ 86011 United States
AU: Axen, G
EM: gaxen@ees.nmt.edu
AF: New Mexico Tech, Dept. of Geology, Socorro, NM 87801 United States
AB: We present new a seismic velocity model that composes the most detailed picture to date of the crustal structure of the southeastern Gulf of California. Wide-angle and multi-channel seismic (MCS) data were collected in 2002 using the R/V Maurice Ewing and a 480-channel, 6 km-long streamer, ocean bottom seismometers and land seismometers each spaced 10-15 km apart along transects. Preliminary wide-angle modeling of the Jalisco continental margin predicts an oceanic crust with a thickness of ~6 km and a continental crust with a thickness of at least 2510 km. A ~100 km zone of transitional crust and ~100 km section of extended continental crust lie between the typical oceanic and continental crusts. Compared with its conjugate rifted margin, the Cabo section of Baja California, the Jalisco margin possesses a wider zone of transitional crust. Initial MCS images of the southeastern Gulf show broad bathymetric highs of oceanic crust at the East Pacific Rise, the Maria Magdalena Rise, and a more lumpy high at the northern end of the Maria Magdalena Knoll. Very little sediment overlies the oceanic crust, only a few small basins are present. Pre-stack time-migrated images of the continental shelf show large sedimentary basins that have filled in lows created by blocks of faulted continental crust. Different periods of faulting, and hence rifting, are distinguished by sedimentary structures and faulted layers of the basins.
DE: 1734 Seismology
DE: 1744 Tectonophysics
SC: Tectonophysics [T]
MN: Fall Meeting 2005