Sea of Cortez bathymetry

Modified from NOAA-NGDC image

Bathymetry of the Sea of Cortez

The northern end of the Gulf is a relatively flat and shallow region, with a bottom of Colorado River Delta and lagoonal fine-grained deposits. This northern area averages around 200 meters depth, with 60 percent of the area shallower than 200 meters (Brusca, 1980). The lower portion of the Gulf, from the Midriff region down, is a deep trough or rift between the two continental blocks (the Pacific and American tectonic plates), with a bottom of typically oceanic crust between them. There is an initial drop in this trough to about 2,400 meters depth just south of the midriff region, and then a more gradual descent to about 3,600 meters by about latitude 23 degrees north. There is also a relatively high heat flow from the seafloor of the gulf, related to the presence of the East Pacific Rise that is widening the Gulf and spreading the Baja California peninsula away from the mainland.