Lake Cahuilla Shoreline
October 11, 2007
Encircling the present day Salton Sea in Imperial and Riverside Counties, California, is the ancient shoreline of Lake Cahuilla. Now long evaporated, part of the lake's previous high-stand can be found as a long, linear feature running for miles around the southeastern end of the Salton Sea. Here it appears as a diagonal change in surface texture, most prominently as a line of streams that suddenly terminate. These are former creeks and seasonal streams that cut channels in the Colorado River sediments in the Salton Trough. When they reached Lake Cahuilla, they ceased carving into the soil. Only modern streams now cross the ancient shoreline.
This Google Earth picture is superficially similar to a previous Earth Science Picture of the Day in the same region: the San Andreas Fault. A close look at the stream morphology between the two pictures, however, shows them to have been formed by very different geological processes. See also the EPOD for June 5, 2007 and for August 17, 2007.