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Tertiary volcanic flow rocks, unit 2 (Pinnacles-Neenach)

Tertiary volcanic flow rocks; minor pyroclastic deposits.
State California
Name Tertiary volcanic flow rocks, unit 2 (Pinnacles-Neenach)
Geologic age Tertiary (22-24 Ma)
Comments two areas separated by San Andreas Fault system
Primary rock type rhyolite
Secondary rock type pyroclastic
Other rock types andesite; dacite
Lithologic constituents
Major
Igneous > Volcanic > Felsic-volcanic > Rhyolite (Flow)
Minor
Igneous > Volcanic > Felsic-volcanic > Rhyolite (Volcaniclastic, volcanic breccia)
Incidental
Igneous > Volcanic > Felsic-volcanic > Rhyolite (Pyroclastic)
Igneous > Volcanic > Felsic-volcanic > Dacite (Flow)
Igneous > Volcanic > Felsic-volcanic > Dacite (Volcaniclastic, volcanic breccia)
Igneous > Volcanic > Mafic-volcanic > Andesite (Flow)
Igneous > Volcanic > Mafic-volcanic > Andesite (Volcaniclastic, volcanic breccia)
Map references
Jennings, C.W., Strand, R.G., and Rogers, T.H., 1977, Geologic map of California: California Division of Mines and Geology, scale 1:750,000.
Unit references
Stanley, R.G., Wilson, D.S., and McCrory, P.A., 2000, Locations and ages of middle Tertiary volcanic centers in coastal California: U.S. Geological Survey Open-File Report 00-154, 27 p., url http://geopubs.wr.usgs.gov/open-file/of00-154/
Matthews, V.,III, 1973, Geology of the Pinnacles volcanic formation and the Neenach volcanic formation and their bearing on the San Andreas fault problem. Unpublished Ph.D dissertation, University of California, Santa Cruz, Santa Cruz, CA.
Weigand, P. W., and Thomas, J. M., 1989, Middle Cenozoic volcanic fields adjacent to the San Andreas fault, central California: Correlation and petrogenesis: in Baldwin, E. J., Foster, J. H., Lewis, W. L., and Hardy, J. K., eds., San Andreas fault - Cajon Pass to Wallace Creek: South Coast Geological Society Guidebook, no. 17, vol. 1, p. 207-222.
Ludington, Steve, and Gray, Karen, 1987, Petrochemical studies of the Pinnacles Wilderness contiguous wilderness study area, Monterey and San Benito Counties, California. U.S. Geological Survey Open-file report 87-135, 9 p.
Jennings, C.W., Strand, R.G., and Rogers, T.H., 1977, Geologic map of California: California Division of Mines and Geology, scale 1:750,000.
Counties Los Angeles - Monterey - San Benito