2009 Portland GSA Annual Meeting (18-21 October 2009)

Paper No. 27
Presentation Time: 9:00 AM-6:00 PM


DAWSON, Timothy E.1, SAUCEDO, George1 and WILLS, Chris2, (1)California Geological Survey, 345 Middlefield Road, MS 520, Menlo Park, CA 94025, (2)California Geological Survey, 801 K Street, MS 12-32, Sacramento, CA 95814, tdawson@conservation.ca.gov

As part of the STATEMAP project, the California Geological Survey has prepared a geologic compilation of the Lodi 30 x 60 minute quadrangle. This map is part of an ongoing effort by CGS to provide 1:100,000-scale regional maps for the Sacramento - San Joaquin Delta area, an area characterized by rapid urbanization, as well as critical habitat and infrastructure critical to the distribution of water within California. Geologic materials in the delta region are described by their age and environment of deposition, both of which correlate with engineering properties of the materials. This map and associated GIS database provides a basic data layer for analysis of levee stability, seismic hazards, and other engineering issues in this area. The map is a synthesis of existing geologic mapping and includes recent 1:24,000 scale mapping of Quaternary deposits by the U.S. Geological Survey, the California Geological Survey, and William Lettis and Associates, as well as older 1:24,000 and 1:62,500-scale geologic mapping. This new compilation also presents a regionally consistent treatment of Quaternary surficial units for the Delta. We anticipate that this data will form a consistent base layer that provides context for more site-specific evaluations of the safety and impacts of existing and proposed infrastructure in this critical area.