Geologic units in San Diego county, California

Additional scientific data in this geographic area

Mesozoic granitic rocks, unit 2 (Peninsular Ranges) (Middle Jurassic to Late Cretaceous) at surface, covers 44 % of this area

Mesozoic granite, quartz monzonite, granodiorite, and quartz diorite

Quaternary alluvium and marine deposits (Pleistocene to Holocene) at surface, covers 12 % of this area

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

pre-Cenozoic granitic and metamorphic rocks undivided (Early Proterozoic to Late Cretaceous) at surface, covers 10 % of this area

Granitic and metamorphic rocks, mostly gneiss and other metamorphic rocks injected by granitic rocks. Mesozoic to Precambrian.

Older Quaternary alluvium and marine deposits (Pleistocene) at surface, covers 6 % of this area

Older alluvium, lake, playa, and terrace deposits.

Mesozoic volcanic rocks, unit 4 (Peninsular Ranges) (Late Jurassic to Early Cretaceous) at surface, covers 5 % 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.

Eocene marine rocks (Paleocene to Oligocene) at surface, covers 5 % of this area

Shale, sandstone, conglomerate, and minor limestone; in part Oligocene and Paleocene.

Mesozoic gabbroic rocks, unit 2 (undivided) (Triassic to Cretaceous) at surface, covers 4 % of this area

Gabbro and dark dioritic rocks; chiefly Mesozoic

Plio-Pleistocene and Pliocene loosely consolidated deposits (Miocene to Pleistocene) at surface, covers 4 % of this area

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

Eocene nonmarine rocks, unit 2 (Southern California) (middle to late Eocene) at surface, covers 3 % of this area

Sandstone, shale, and conglomerate.

Pliocene marine rocks (Miocene to Pleistocene) at surface, covers 2 % of this area

Sandstone, siltstone, shale, and conglomerate; in part Pleistocene and Miocene.

Schist of various types and ages, unit 1 (Peninsular Ranges) (Triassic(?)) at surface, covers 2 % of this area

Schists of various types; mostly Paleozoic or Mesozoic age; some Precambrian

pre-Cenozoic metasedimentary and metavolcanic rocks undivided (Early Proterozoic to Cretaceous) at surface, covers 1 % of this area

Undivided pre-Cenozoic metasedimentary and metavolcanic rocks of great variety. Mostly slate, quartzite, hornfels, chert, phyllite, mylonite, schist, gneiss, and minor marble.

Jurassic marine rocks, unit 4 (Peninsular Ranges and Western Transverse Ranges) (Paleozoic(?) to Late Jurassic) at surface, covers 0.7 % of this area

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

Miocene marine rocks (Oligocene to Pliocene) at surface, covers 0.7 % of this area

Sandstone, shale, siltstone, conglomerate and breccia; in part Pliocene and Oligocene.

Miocene nonmarine rocks (Oligocene to Pleistocene) at surface, covers 0.6 % of this area

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

Tertiary nonmarine rocks, undivided (Paleocene to Pliocene) at surface, covers 0.4 % of this area

Undivided Tertiary sandstone, shale, conglomerate, breccia, and ancient lake deposits.

Cretaceous marine rocks (in part nonmarine), unit 1 (Coast Ranges) (Early to Late Cretaceous) at surface, covers 0.4 % of this area

Undivided Cretaceous sandstone, shale, and conglomerate; minor nonmarine rocks in Peninsular Ranges

Upper Cretaceous marine rocks, unit 1 (Upper Great Valley Sequence) (Late Cretaceous) at surface, covers 0.4 % of this area

Upper Cretaceous sandstone, shale, and conglomerate

Tertiary volcanic flow rocks, unit 11 (Jacumba) (Tertiary (12-19 Ma)) at surface, covers 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Tertiary volcanic flow rocks, unit 10 (Alverson) (Tertiary (14-18 Ma)) at surface, covers < 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Miocene marine rocks (?) (Miocene(?) or Pliocene(?)) at surface, covers < 0.1 % of this area

Miocene marine rocks (?)

Cretaceous marine rocks (in part nonmarine) (?), unit 2 (Jacumba) (Late Cretaceous(?) to Miocene(?)) at surface, covers < 0.1 % of this area

Undivided Cretaceous sandstone, shale, and conglomerate; minor nonmarine rocks in Peninsular Ranges (?)

Quaternary volcanic flow rocks, unit 8 (Peninsular Ranges) (Quaternary) at surface, covers < 0.1 % of this area

Quaternary volcanic flow rocks; minor pyroclastic deposits; in part Pliocene and Miocene.

Tertiary volcanic flow rocks, unit 8 (Southern California Basin) (Tertiary (8-25 Ma; most near 15)) at surface, covers < 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Limestone of probable Paleozoic or Mesozoic age (Paleozoic to Mesozoic) at surface, covers < 0.1 % of this area

Limestone, dolomite, and marble whose age is uncertain but probably Paleozoic or Mesozoic