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: http://pubs.usgs.gov/imap/i1874/

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 (?)