A Geophysical Study of the Hydrogeology of the Carrizo Plain Area, San Luis Obispo County, California
COOPER, JON W., Kennedy/Jenks/Chilton, Bakersfield, CA
This investigation was conducted to attempt to locate structural geologic features and variations in aquifer characteristics in an area within the Carrizo plain, San Luis Obispo County, California. The investigation included a review of the established geologic knowledge for the region, followed by field studies. The field studies included surface magnetometer surveys, thermal borehole logging, and a piezometric level survey. Existing borehole electric logs were obtained. The conclusions of the investigation were then derived from a collective interpretation.
The investigation concluded that a fault appears to extend beneath the valley fill in the northwestern part of the area, and that a subsurface basaltic dike is apparently located in the southeastern part of the area. Evaluations indicate that the valley has a deep aquifer overlain by a confining clay-rich layer in the central part of the area. Areal and depth-related variations in water quality are probably influenced by the presence of evaporites near Soda Lake and in the region near the San Andreas fault.
AAPG Search and Discovery Article #91009©1991 AAPG-SEPM-SEG-SPWLA Pacific Section Annual Meeting, Bakersfield, California, March 6-8, 1991 (2009)