Hi-res MCS

The major boundary zone between the Pacific and North America plates continues southward from the San Andreas fault system into the Gulf of California. Across this boundary, extension and strike-slip faulting is causing the Baja California peninsula to separate away from mainland Mexico, thereby opening the Gulf of California. The northern Gulf region contains the transition from an oceanic-type plate boundary (with deformation localized on transform faults and spreading centers) to continental deformation of the San Andreas and related fault systems.

From May 22 to June 12, 1999, we surveyed the northern gulf region (Delfin basin, Wagner basin, and regions to the west) with a portable, high-resolution MCS system that belongs to Columbia University. We used the ship Francisco de Ulloa, which is operated by the Centro de Investigacion Cientifica y Educacion Superior de Ensenada (CICESE), Ensenada, Mexico. The data imaged the active and young faults in this region as well as the youngest strata in the gulf basins in this area. As we analyze these data, we hope to determine how the young faults beneath the Gulf of California are kinematically connected to the active faults on land to the west on the Baja California peninsula. This will help us to understand the exact location of the continent-ocean transition zone at present, and how deformation is passing from the oceanic spreading regime to the continental deformational province.

This project was funded by the National Science Foundation of the USA and by CONACyT and CICESE. It is collaborative with Dr. Arturo Martin-Barajas and colleagues at the Centro de Investigacion Cientifica y Educacion Superior de Ensenada (CICESE), Ensenada, Mexico; and with Mike Steckler, John Diebold, and Greg Mountain at Lamont-Doherty Earth Observatory of Columbia University. 

Other members of the shipboard scientific party were: Patricia Persaud (Caltech), Antonio Gonzalez, Jose Luis Garcia Puga and Sergio Paz (CICESE), Peter Buhl and Erich Scholz (LDEO).

Click here for a preliminary plot of the cruise track.

Click here for a plot of the cruise track overlain on newly derived bathymetric contours for the northern Gulf area.

We thank Landmark Graphics Corporation for providing software used in this project, through the University Grants Program.

References:


Persaud, P., J. M. Stock, M. S. Steckler, A. Martin-Barajas, J. B. Diebold, A. Gonzalez-Fernandez, G. S. Mountain, Active deformation and shallow structure of the Wagner, Consag, and Delfin Basins, northern Gulf of California, Mexico, J. Geophys. Res., vol. 108, No. B7, 2355, doi:10.1029/2002JB001937, 31 July 2003.

All of the seismic lines collected during this cruise can be accessed over the internet through the free computer software GeoMapApp .