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Geologic units in Shasta county, California

Additional scientific data in this geographic area

Quaternary volcanic flow rocks, unit 1 (Cascade Volcanic Field) (Quaternary) at surface, covers 19 % of this area

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

Tertiary volcanic flow rocks, unit 17 (Cascade Range) (Tertiary (2-24 Ma)) at surface, covers 16 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Carboniferous marine rocks, unit 4 (Eastern Klamath Mountains) (Mississippian to Early Permian) at surface, covers 11 % of this area

Shale, sandstone, conglomerate, limestone, dolomite, chert, hornfels, marble, quartzite; in part pyroclastic rocks

Paleozoic metavolcanic rocks, unit 1 (Eastern Klamath Mountains) (Devonian and Permian) at surface, covers 7 % of this area

Undivided Paleozoic metavolcanic rocks. Mostly flows, breccia and tuff, including greenstone, diabase, and pillow lavas; minor interbedded sedimentary rocks

Triassic marine rocks, unit 2 (Eastern Klamath Mountains) (Middle to Late Triassic) at surface, covers 7 % of this area

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Plio-Pleistocene and Pliocene loosely consolidated deposits (Miocene to Pleistocene) at surface, covers 6 % of this area

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

Recent (Holocene) volcanic flow rocks, unit 1 (Cascade Volcanic Field) (Holocene) at surface, covers 4 % of this area

Recent (Holocene) volcanic flow rocks; minor pyroclastic deposits; in part Pleistocene.

Lithology: andesite; dacite

Tertiary pyroclastic and volcanic mudflow deposits, unit 9 (Cascade Range) (Tertiary (2-24 Ma)) at surface, covers 4 % of this area

Tertiary pyroclastic and volcanic mudflow deposits.

Quaternary alluvium and marine deposits (Pliocene to Holocene) at surface, covers 3 % of this area

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

Upper Cretaceous marine rocks, unit 1 (Upper Great Valley Sequence) (Late Cretaceous) at surface, covers 2 % of this area

Upper Cretaceous sandstone, shale, and conglomerate

Ultramafic rocks, chiefly Mesozoic, unit 1 (Trinity Ophiolite) (Ordovician) at surface, covers 2 % of this area

Ultramafic rocks, mostly serpentine. Minor peridotite, gabbro, and diabase. Chiefly Mesozoic unit 1

Mesozoic granitic rocks, unit 5 (Klamath Mountains) (Jurassic to early Cretaceous) at surface, covers 2 % of this area

Mesozoic granite, quartz monzonite, granodiorite, and quartz diorite

Lower Cretaceous marine rocks (Early Cretaceous) at surface, covers 2 % of this area

Lower Cretaceous sandstone, shale, and conglomerate

Jurassic marine rocks, unit 5 (Northern Sierra Nevada and Eastern Klamath Mountains) (Devonian to Late Jurassic) at surface, covers 2 % of this area

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

Mesozoic volcanic rocks, unit 5 (Northern Sierra Nevada and Eastern Klamath Mountains) (Late Permian(?) to Jurassic) at surface, covers 2 % 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 nonmarine rocks, unit 1 (Northern and Central California) (Eocene) at surface, covers 2 % of this area

Sandstone, shale, and conglomerate.

Schist of various types and ages, unit 7 (Klamath Mountains) (Devonian) at surface, covers 1 % of this area

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

Lithology: schist; amphibolite; marble

Mesozoic granitic rocks, unit 4 (Klamath Mountains and Northern Sierra Nevada) (Devonian) at surface, covers 1.0 % of this area

Mesozoic granite, quartz monzonite, granodiorite, and quartz diorite

Recent (Holocene) pyroclastic and volcanic mudflow deposits, unit 1 (Cascade Volcanic Field) (Holocene) at surface, covers 0.5 % of this area

Recent (Holocene) pyroclastic and volcanic mudflow deposits; in part Pleistocene.

Devonian marine rocks, unit 2 (Eastern Klamath Mountains) (Devonian) at surface, covers 0.3 % of this area

Limestone and dolomite, sandstone and shale; in part tuffaceous

Quaternary glacial deposits (Pleistocene) at surface, covers 0.3 % of this area

Glacial till and moraines. Found at high elevations mostly in the Sierra Nevada and Klamath Mountains.

Lithology: glacial drift

Mesozoic gabbroic rocks, unit 1 (Trinity Ophiolite) (Ordovician) at surface, covers 0.3 % of this area

Gabbro and dark dioritic rocks; chiefly Mesozoic

Lithology: gabbro; diorite

Permian marine sedimentary rocks, unit 4 (Eastern Klamath Mountains) (Early Permian) at surface, covers 0.3 % of this area

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Lithology: limestone

Paleozoic marine rocks, undivided, unit 7 (Southeastern Klamath Mountains) (Devonian(?)) at surface, covers 0.2 % of this area

Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite

Lithology: gneiss; amphibolite

Mesozoic granitic rocks, unit 6 (Eastern Klamath Mountains) (Permian) at surface, covers 0.2 % of this area

Mesozoic granite, quartz monzonite, granodiorite, and quartz diorite

Lithology: diorite

Miocene nonmarine rocks (Oligocene to Pleistocene) at surface, covers 0.2 % of this area

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

Ultramafic rocks, chiefly Mesozoic, unit 2 (Western Sierra Nevada and Klamath Mountains) (Late Proterozoic(?) to Early Jurassic) at surface, covers 0.1 % of this area

Ultramafic rocks, mostly serpentine. Minor peridotite, gabbro, and diabase. Chiefly Mesozoic unit 2

Paleozoic marine rocks, undivided, unit 9 (Western Klamath Mountains) (Devonian to Jurassic) at surface, covers 0.1 % of this area

Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite

Paleozoic and Permo-Triassic granitic rocks, unit 1 (Eastern Klamath Mountains) (Permian) at surface, covers < 0.1 % of this area

Paleozoic and Permo-Triassic granitic rocks in the San Gabriel and Klamath Mountains

pre-Cenozoic metasedimentary and metavolcanic rocks undivided (Early Proterozoic to Cretaceous) at surface, covers < 0.1 % 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.

Undated granitic rocks, unit 2 (Western Klamath Mountains) (Late Triassic to Early Jurassic) at surface, covers < 0.1 % of this area

Undated granitic rocks unit 2