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Geologic Map of Yosemite Valley

Geologic Map of Yosemite Valley region

This map was scanned from the Geologic Map of Yosemite National Park and Vicinity, California, U.S. Geological Survey Miscellaneous Investigations Series Map I-1874 by N. King Huber, Paul C. Bateman, and Clyde Wahrhaftig, published in 1989. The entire map is available from the U.S. Geological Survey:

For a general explanation of plutonic rocks, click here.

Explanation of Symbols:

Qal: Quaternary Alluvium

Includes stream deposits, meadow deposits, and glacial outwash (Quaternary)

Qtl: Talus (Holocene)

Rock waste derived from cliffs. Only especially extensive areas shown

Qti: Tioga Till

Moraines usually sharp crested with abundant boulders at surface (Pleistocene)

Qta: Tahoe Till

Moraines usually crested, but subdued, with scattered, weathered boulders at surface.

Qpt: Pre-Tahoe Till

Moraines hummocky and dissected. May include Sherwin tills (Pleistocene).

Khd: Half Dome granodiorite

Medium grained biotite hornblende granodiorite with conspicuous crystals of sphene. Locally porphyritic with abundant large phenocrysts of potassium feldspar. Age 86-88 Ma

Kkc: Granodiorite of Kuna Crest

Dark-colored, fine- to medium-grained, biotite-hornblende granodiorite. Age 88 Ma

Ks: Sentinel Granodiorite

Coarse-grained, dark-gray, biotite-hornblende granodiorite with abundant sphene. Age 93 Ma

Kbv: Bridalveil Granodiorite

Fine-grained hornblende-biotite granodiorite and granite.

Kic: Granodiorite of Illilouette Creek

Medium- to coarse-grained mafic hornblende-biotite granodiorite, tonalite and granite. Age about 100 Ma

Kid: Quartz diorite

Dark fine-grained rock rich in hornblende. Occurs as irregular intrusive masses cross-cutting El Capitan and Taft Granites on north side of Yosemite Valley.

Kt: Taft Granite

Fine- to coarse-grained white to gray biotite granite and biotite granodiorite. Locally porphyritic with phenocrysts of potassium feldspar. Age 96 Ma

Kec: El Capitan Granite

Coarse-grained, white to light-gray biotite granite and biotite granodiorite. Commonly porphyritic with blocky phenocrysts of potassium feldspar and conspicuous quartz grains. Age about 102 Ma

Kga: Tonalite of the Gateway

Also known as Bass Lake Tonalite. Medium-grained biotite-hornblende tonalite. Varies to granodiorite and quartz diorite. Age 114 Ma

Kar: Granodiorite of Arch Rock

Medium-grained, biotite granodiorite, commonly with poikilitic potassium feldspar. Age 116 Ma

KJdg: Diorite and gabbro

Occurs as generally small, irregularly shaped bodies throughout map area, including the Rockslides adjacent to El Capitan. Age Jurassic to Cretaceous

Jms: Metasedimentary rock

Hornfels and other metamorphic rocks. Jurassic (?)

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