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The exposed geology of the Yosemite area includes primarily granitic rocks with some older metamorphic rock. The first rocks were laid down in Precambrian times, when the area around Yosemite National Park was on the edge of a very young North American continent. The sediment that formed the area first settled in the waters of a shallow sea, and compressive forces from a subduction zone in the mid-Paleozoic fused the seabed rocks and sediments, appending them to the continent. Heat generated from the subduction created island arcs of volcanoes that were also thrust into the area of the park. In time, the igneous and sedimentary rocks of the area were later heavily metamorphosed.
Cathedral Peak is part of the Cathedral Range, a mountain range in the south-central portion of Yosemite National Park in eastern Mariposa and Tuolumne Counties. The range is an offshoot of the Sierra Nevada. The peak which lends its name to the range derives its name from its cathedral-shaped peak, which was formed by glacial activity: the peak remained uneroded above the glaciers in the Pleistocene.
Aplite is an intrusive igneous rock that has a granitic composition. Aplites are fine-grained to aphanitic and may consist of only quartz and feldspar or the term may refer to any leucocratic (pale-coloured) minor intrusion of that grain size. They are associated with the later stages of many larger intermediate to felsic intrusions.
Quartz monzonite is an intrusive, felsic, igneous rock that has an approximately equal proportion of orthoclase and plagioclase feldspars. It is typically a light colored phaneritic (coarse-grained) to porphyritic granitic rock. The plagioclase is typically intermediate to sodic in composition, andesine to oligoclase. Quartz is present in significant amounts. Biotite and/or hornblende constitute the dark minerals. Because of its coloring, it is often confused with granite, but whereas granite contains more than 20% quartz, quartz monzonite is only 5–20% quartz. Rock with less than five percent quartz is classified as monzonite. A rock with more alkali feldspar is a syenite whereas one with more plagioclase is a quartz diorite. The fine grained volcanic rock equivalent of quartz monzonite is quartz latite.
Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form intrusions, such as batholiths, dikes, sills, laccoliths, and volcanic necks.
Granodiorite is a coarse-grained (phaneritic) intrusive igneous rock similar to granite, but containing more plagioclase feldspar than orthoclase feldspar.
The Sierra Nevada Batholith is a large batholith that is approximately 400 miles long and 60-80 miles wide which forms the core of the Sierra Nevada mountain range in California, exposed at the surface as granite.
The Cathedral Peak Granodiorite (CPG) was named after its type locality, Cathedral Peak in Yosemite National Park, California. The granodiorite forms part of the Tuolumne Intrusive Suite, one of the four major intrusive suites within the Sierra Nevada. It has been assigned radiometric ages between 88 and 87 million years and therefore reached its cooling stage in the Coniacian.
The Idaho Batholith is a granitic and granodioritic batholith of Cretaceous-Paleogene age that covers approximately 25,000 square kilometres (9,700 sq mi) of central Idaho and adjacent Montana. The batholith has two lobes that are separate from each other geographically and geologically. The Bitterroot lobe is the smaller lobe and the larger lobe is the Atlanta lobe. The Bitterroot lobe is in the north and is separated from the larger Atlanta lobe in the south by the Belt Supergroup metamorphic rocks that compose the Salmon River Arch. Much of the Atlanta and Bitterroot lobes are in the Idaho Batholith ecoregion.
Half Dome Granodiorite is granodiorite found in a region on and near Half Dome, in Yosemite National Park, California, United States. The granodiorite forms part of the Tuolumne Intrusive Suite, one of the four major intrusive suites within the Sierra Nevada.
El Capitan Granite is a type of granite, in a large area near El Capitan, in Yosemite National Park, California, United States. The granite forms part of the Tuolumne Intrusive Suite, one of the four major intrusive suites within the Sierra Nevada.
Kuna Crest Granodiorite, is found, in Yosemite National Park, United States. The granodiorite forms part of the Tuolumne Intrusive Suite, one of the four major intrusive suites within the Sierra Nevada. Of the Tuolumne Intrusive Suite, it is the oldest and darkest rock.
Sentinel granodiorite is a type of granodiorite found in Yosemite National Park. It is a poorly understood western "outlier" of the ~93-85-Ma Tuolumne Intrusive Suite of the Sierra Nevada batholith. It is only slightly older than the undated Yosemite Creek Granodiorite and the Kuna Crest Granodiorite.
The Tuolumne Intrusive Suite is the youngest and most extensive of the intrusive suites of Yosemite National Park, and also comprises about 1/3 of the park's area. The Suite includes Half Dome Granodiorite, Cathedral Peak Granite, and Kuna Crest Granodiorite.
The Intrusive Suite of Buena Vista Crest is an intrusive suite which extends 30 kilometres (19 mi) southward, from Yosemite Valley to Yosemite National Park's southeastern boundary, into plutons of the Sierra Nevada Batholith, which are slightly older. These intrusive suites also include
- Fine Gold Intrusive Suite
- Intrusive Suite of Jack Main Canyon
- Intrusive Suite of Merced Peak
- Intrusive Suite of Sonora Pass
- Intrusive Suite of Yosemite Valley
- Tuolumne Intrusive Suite
The Intrusive Suite of Yosemite Valley is one of several intrusive suites in Yosemite National Park. These also include
- Fine Gold Intrusive Suite
- Intrusive Suite of Buena Vista Crest
- Intrusive Suite of Jack Main Canyon
- Intrusive Suite of Merced Peak
- Intrusive Suite of Sonora Pass
- Tuolumne Intrusive Suite
- Johnson Granite Porphyry
The Intrusive Suite of Sonora Pass is one of several intrusive suites in Yosemite National Park. These also include
- Fine Gold Intrusive Suite
- Intrusive Suite of Buena Vista Crest
- Intrusive Suite of Jack Main Canyon
- Intrusive Suite of Merced Peak
- Intrusive Suite of Yosemite Valley
- Tuolumne Intrusive Suite
Mammoth Peak is a mountain in the area of Tuolumne Meadows, Yosemite National Park, California. The summit is a class 1-2 cross-country hike that features river crossings and boulder scrambling. The peak lies at the northern end of the Kuna Crest and is close to California State Route 120. From the road, its summit appears rounded and quite rocky. Though Mammoth Peak is not as popular as other nearby peaks, its relatively easily accessed summit affords tremendous views of Mount Gibbs, Mount Dana, and Mount Lewis.
Kuna Crest is a mountain range near Tuolumne Meadows, in Yosemite National Park, California.
The Intrusive Suite of Merced Peak is one of several intrusive suites in Yosemite National Park. These also include:
- Fine Gold Intrusive Suite
- Intrusive Suite of Buena Vista Crest
- Intrusive Suite of Jack Main Canyon
- Intrusive Suite of Sonora Pass
- Intrusive Suite of Yosemite Valley
- Johnson Granite Porphyry
- Tuolumne Intrusive Suite
References
- 1 2 3 Calkins, Frank C. "The Granitic Rocks of the Yosemite Region".
- ↑ Glazner, Allen F, Stock, Greg M. (2010). Geology Underfoot in Yosemite. Mountain Press, p. 53. ISBN 978-0-87842-568-6.
- ↑ Bracciali, Laura; Paterson, Scott R.; Memeti, Vali; Rocchi, Sergio; Matzel, J.; Mundil, Roland (2008). "Build-up of the Tuolumne Batholith, California: the Johnson Granite Porphyry" (published January 1, 2008).
- ↑ Calkins, F.C. (1930). "National Geologic Map Database".
- 1 2 3 Bracciali, Laura; Memeti, Vali; Paterson, Scott R.; Rocchi, Sergio (January 2008). "Build-up of the Tuolumne Batholith, California: the Johnson Granite Porphyry". ResearchGate.
- ↑ Bracciali, Laura; Paterson, Scott; Memeti, Valbone; Rocchi, Sergio; Matzel, Jennifer; Mundil, Roland (2008). "Build-up of the Tuolumne Batholith, California: the Johnson Granite Porphyry".
- ↑ Titus, Sarah J.; Clark, Ryan; Tikoff, Basil (September 2005). "Geologic and geophysical investigation of two fine-grained granites, Sierra Nevada Batholith, California: Evidence for structural controls on emplacement and volcanism". Geological Society of America Bulletin.
{{cite web}}: CS1 maint: date and year (link) - ↑ Titus, S.; Clark, R.; Tikoff, S. (September 1, 2005). "Geologic and geophysical investigation of two fine-grained granites, Sierra Nevada Batholith, California: Evidence for structural controls on emplacement and volcanism". Geological Society of America Bulletin. 117 (9): 1256. doi:10.1130/B25689.1. S2CID 129298834.