Geology Map of Mount Diablo
Geologic Map
Legend
Quarternary - surficial deposits
Quarternary - landslide deposits
Jurassic/Cretaceous - dark
greenish-gray shale sandstone
interbeds (Knoxville Formation)
Miocene/Pliocene - non-marine
sandstone, siltstone, and conglomerate
Miocene - marine fossiliferous
sandstone and shale
Jurassic/Cretaceous - melange
(Franciscian Complex)
Jurassic - chert and basalt with some graywacke and shale
(Franciscan Complex)
Miocene - silicic intrusive rocks
Jurassic - basalt and diabase
(Coast Range Ophiolite)
Eocene - massive pebbly sandstone
with shale
Jurassic - serpentinite (Coast Range Ophiolite)
Cretaceous - shale, siltstone, and
sandstone (Great Valley Sequence)
Silica carbonate rock (altered serpentinite)
Thrust Fault
Thrust Fault - inferred
Fault
Fault - Inferred
Roads
Streams
Data Source Preliminary Geologic Map Emphazing Bedrock Formations in Contra Costa County, California. Compiled by R.W. Graymer, D.L. Jones, and E.E. Brabb U.S. Geological Survey Open-File Report 94-622 Arc/Info Data Files
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Simplified with minor modifications by Roi Peers and Craig Lyon, September 1996.
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Geologic Information Systems Map by Eric R. Sheehan, Martinez, California.