Daniel Brothers, Woods Hole Coastal and Marine Science Center, Massachusetts; University of California, San Diego
Alistair Harding, University of California, San Diego
Antonio González-Fernández, CICESE, Ensenada, Mexico
W. Steven Holbrook, University of WyomingFollow
Graham Kent, University of Nevada
Neal Driscoll, University of California, San Diego
John Fletcher, CICESE, Ensenada, Mexico
Dan Lizarralde, Woods Hole Oceanographic Institution, Massachusetts
Paul Umhoefer, Northern Arizona University
Gary Axen, New Mexico Institute of Mining and Technology
Subduction of the Farallon plate beneath northwestern Mexico stalled by ∼12 Ma when the Pacific-Farallon spreading-ridge approached the subduction zone. Coupling between remnant slab and the overriding North American plate played an important role in the capture of the Baja California (BC) microplate by the Pacific Plate. Active-source seismic reflection and wide-angle seismic refraction profiles across southwestern BC (∼24.5N) are used to image the extent of remnant slab and study its impact on the overriding plate. We infer that the hot, buoyant slab detached ∼40 km landward of the fossil trench. Isostatic rebound following slab detachment uplifted the margin and exposed the Magdalena Shelf to wave-base erosion. Subsequent cooling, subsidence and transtensional opening along the shelf (starting ∼8 Ma) starved the fossil trench of terrigenous sediment input. Slab detachment and the resultant rebound of the margin provide a mechanism for rapid uplift and exhumation of forearc subduction complexes. © 2012 by the American Geophysical Union.
Geophysical Research Letters
Brothers, Daniel; Harding, Alistair; González-Fernández, Antonio; Holbrook, W. Steven; Kent, Graham; Driscoll, Neal; Fletcher, John; Lizarralde, Dan; Umhoefer, Paul; and Axen, Gary (2012). "Farallon Slab Detachment and Deformation of the Magdalena Shelf, Southern Baja California." Geophysical Research Letters 39.L09307, 1-7.