Gabbro is a phaneritic (coarse-grained), mafic intrusive igneous rock formed from the slow cooling of magnesium-rich and iron-rich magma into a holocrystalline mass deep beneath the Earth's surface. Slow-cooling, coarse-grained gabbro is chemically equivalent to rapid-cooling, fine-grained basalt. Much of the Earth's oceanic crust is made of gabbro, formed at mid-ocean ridges. Gabbro is also found as plutons associated with continental volcanism. Due to its variant nature, the term gabbro may be applied loosely to a wide range of intrusive rocks, many of which are merely "gabbroic". By rough analogy, gabbro is to basalt as granite is to rhyolite.
Amphibolite is a metamorphic rock that contains amphibole, especially hornblende and actinolite, as well as plagioclase feldspar, but with little or no quartz. It is typically dark-colored and dense, with a weakly foliated or schistose (flaky) structure. The small flakes of black and white in the rock often give it a salt-and-pepper appearance.
Diorite is an intrusive igneous rock formed by the slow cooling underground of magma that has a moderate content of silica and a relatively low content of alkali metals. It is intermediate in composition between low-silica (mafic) gabbro and high-silica (felsic) granite.
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.
Lamprophyres are uncommon, small-volume ultrapotassic igneous rocks primarily occurring as dikes, lopoliths, laccoliths, stocks, and small intrusions. They are alkaline silica-undersaturated mafic or ultramafic rocks with high magnesium oxide, >3% potassium oxide, high sodium oxide, and high nickel and chromium.
Granodiorite is a coarse-grained (phaneritic) intrusive igneous rock similar to granite, but containing more plagioclase feldspar than orthoclase feldspar.
Monzonite is an igneous intrusive rock, formed by slow cooling of underground magma that has a moderate silica content and is enriched in alkali metal oxides. Monzonite is composed mostly of plagioclase and alkali feldspar.
Yosemite National Park is located in the central Sierra Nevada of California. Three wilderness areas are adjacent to Yosemite: the Ansel Adams Wilderness to the southeast, the Hoover Wilderness to the northeast, and the Emigrant Wilderness to the north.
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 Piégut-Pluviers Granodiorite is situated at the northwestern edge of the Variscan Massif Central in France. Its cooling age has been determined as 325 ± 14 million years BP.
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.
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 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.
Johnson Granite Porphyry is found in Tuolumne Meadows, Yosemite National Park.
