FAULT FEATURES OF SALTON BASIN, CALIFORNIA^ 



JOHN S. BROWN 

 U. S. Geological Survey 



OUTLINE 



General Features 



Surrounding Mountains 



The Basin Floor 



Stratigraphy 



Formation of Salton Basin 



The Indio Fault 



Faults Southwest of Salton Basin 



Valleys Formed by Faulting 



Type of Faulting 



Age of Faulting 



References 



GENERAL FEATURES 



The Salton Basin is a great natural depression in the south- 

 eastern corner of California (PI. I). Its lowest elevation is 273.5 

 feet below sea-level,^ and the lowest part of the basin is now occupied 

 by the more or less ephemeral lake known as Salton Sea, which was 

 created in 1905 by the accidental escape of Colorado River during 

 the diversion of irrigating water to Imperial Valley. Physio- 

 graphically, Salton Basin is continuous with the depression occupied 

 by the Gulf of California, and the only topographic barrier that 

 prevents the access of sea-water to the basin is a delta dam built 

 up in recent geologic time by Colorado River. At its lowest point 

 this dam is less than 50 feet above sea-level. 



SURROUNDING MOUNTAINS 



The axis of the basin trends southeast-northwest, and at its 

 northwest extremity the basin narrows nearly to a point, being 

 connected by San Gorgonio Pass to the Pacific Slope. Mountain 

 ranges from 2,000 to 10,000 feet in height flank the basin on the 



' Published by permission of the Director of the United States Geologic Survey. 



2 There is some question as to whether the exact elevation of the lowest point of 

 the basin, now covered by Salton Sea, is —273.5 or —287 feet. See U.S. Geol. Surv. 

 Water-Supply Paper 213, p. 30, for discussion and statement that former figure is 

 probably correct. 



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