This geologic map database and cross sections presents new geologic mapping by the authors in addition to new radiometric ages and tephrochronology of volcanic rock units. The map database depicts the general distribution of bedrock and surficial deposits in the mapped area and provides a context for interpreting the evolution of active faults in the region. Together with the accompanying PDF file (SIM2858-pamphlet.pdf), it provides current information on the geologic structure and stratigraphy of the area covered. The database delineates map units that are identified by general age and lithology following the stratigraphic nomenclature of the U.S. Geological Survey. The scale of the source maps limits the spatial resolution (scale) of the database to 1:24,000 or smaller.
Additional publication details
USGS Numbered Series
Geology, tephrochronology, radiometric ages, and cross sections of the Mark West Springs 7.5 degree quadrangle, Sonoma and Napa counties, California
Scientific Investigations Map
2 sheets, 48 by 36 inches; 16 p. pamphlet; datafiles