Geologic units in Sacramento county, California

Additional scientific data in this geographic area

Quaternary alluvium and marine deposits (Pleistocene to Holocene) at surface, covers 62 % of this area

Alluvium, lake, playa, and terrace deposits; unconsolidated and semi-consolidated. Mostly nonmarine, but includes marine deposits near the coast.

Plio-Pleistocene and Pliocene loosely consolidated deposits (Miocene to Pleistocene) at surface, covers 26 % of this area

Pliocene and/or Pleistocene sandstone, shale, and gravel deposits; in part Miocene.

Mesozoic volcanic rocks, unit 2 (Western Sierra Foothills and Western Klamath Mountains) (Jurassic) at surface, covers 4 % of this area

Undivided Mesozoic volcanic and metavolcanic rocks. Andesite and rhyolite flow rocks, greenstone, volcanic breccia and other pyroclastic rocks; in part strongly metamorphosed. Includes volcanic rocks of Franciscan Complex: basaltic pillow lava, diabase, greenstone, and minor pyroclastic rocks.

Miocene nonmarine rocks (Oligocene to Pleistocene) at surface, covers 3 % of this area

Sandstone, shale, conglomerate, and fanglomerate; in part Pliocene and Oligocene.

Jurassic marine rocks, unit 1 (Western Sierra Nevada and Western Klamath Mountains) (Triassic to Late Jurassic) at surface, covers 2 % of this area

Shale, sandstone, minor conglomerate, chert, slate, limestone; minor pyroclastic rocks

Older Quaternary alluvium and marine deposits (Pleistocene) at surface, covers 1 % of this area

Older alluvium, lake, playa, and terrace deposits.

Eocene nonmarine rocks, unit 1 (Northern and Central California) (Eocene) at surface, covers 1 % of this area

Sandstone, shale, and conglomerate.

Mesozoic granitic rocks, unit 3 (Sierra Nevada, Death Valley area, Northern Mojave Desert and Transverse Ranges) (Permian to Tertiary; most Mesozoic) at surface, covers 0.5 % of this area

Mesozoic granite, quartz monzonite, granodiorite, and quartz diorite