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Cathedral Peak (California)
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. Geography Cathedral Peak has a subsidiary summit to the west called Eichorn Pinnacle, for Jules Eichorn, who first ascended a class 5.4 route to its summit on July 24, 1931, with Glen Dawson. In 1869, John Muir wrote in ''My first summer in the Sierra'': Geology The Cathedral Peak Granodiorite of Cathedral Peak is an intrusion into an area of older intrusive (or plutonic) and metamorphic rock in the Sierra Nevada Batholith. It is part of a grouping of intrusions called the Tuolumne Intrusive Suite. Cathedral Peak is the youngest of the rock formations in the Suite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sierra Peaks Section
The Sierra Peaks Section (SPS) is a mountaineering society within the Angeles Chapter of the Sierra Club that serves to provide mountaineering activities for Sierra Club members in the Sierra Nevada, and to honor mountaineers who have summited Sierra Nevada peaks. History The Sierra Peaks Section was established in 1955. The Section maintains historic summit registers at Bancroft Library on the University of California, Berkeley campus. Membership To become a member of the SPS, one must be a Sierra Club member and have climbed at least six peaks on the SPS List; it is not necessary that the peaks be Emblem peaks. For verification purposes, two of those ascents must be done on an official SPS trip. Especially accomplished members are award with ''emblems'', with the following grades (from highest to lowest): * Third List Completion * Second List Completion * First List Completion * Master Emblem * Senior Emblem * Emblem Upon receiving one of the normal emblems, members may be re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jules Eichorn
Jules Marquard Eichorn (February 7, 1912 – February 15, 2000) was an American mountaineer, environmentalist, and music teacher. Early years Jules Marquard Eichorn was born in San Francisco on February 7, 1912, to Hilmar and Frieda Eichorn, who were immigrants from Germany. As a youngster, he often hiked on the slopes of Mount Tamalpais in Marin County, California with his parents and siblings. He showed musical talent and began studying violin from Ansel Adams at a young age. In 1927, he began piano lessons, and his first instructor was Ansel Adams. Eichorn was also Adams's first piano student. That summer, Eichorn joined Adams on the Sierra Club annual High Trip, which included a climb of Alta Peak in Sequoia National Park. That climb sparked the 15-year-old Eichorn's love of mountaineering. Eichorn worked for Ansel Adams washing photographic prints and hauling photographic equipment in exchange for piano lessons, and their friendship lasted until Adams's death in 1984 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glaciers
A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as crevasses and seracs, as it slowly flows and deforms under stresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms such as cirques, moraines, or fjords. Although a glacier may flow into a body of water, it forms only on land and is distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water. On Earth, 99% of glacial ice is contained within vast ice sheets (also known as "continental glaciers") in the polar regions, but glaciers may be found in mountain ranges on every continent other than the Australian mainland, including Oceania's high-latitude oceanic island countries such as New Zealand. Between latitudes 35°N and 35°S, glaciers occur only ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Pleistocene
The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as Upper Pleistocene from a Stratigraphy, stratigraphic perspective. It is intended to be the fourth division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently defined as the time between c. 129,000 and c. 11,700 years ago. The Late Pleistocene equates to the proposed Tarantian Age of the geologic time scale, preceded by the officially ratified Chibanian (formerly known as Middle Pleistocene) and succeeded by the officially ratified Greenlandian. The estimated beginning of the Tarantian is the start of the Eemian interglacial period (Marine Isotope Stage 5). It is held to end with the termination of the Younger Dryas, some 10th millennium BC, 11,700 years ago when the Holocene Epoch began. The term Upper Pleistocene is currently in use as a provisional or "quasi-formal" designation by the International Union of Geological ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nunatak
A nunatak (from Inuit ''nunataq'') is the summit or ridge of a mountain that protrudes from an ice field or glacier that otherwise covers most of the mountain or ridge. They are also called glacial islands. Examples are natural pyramidal peaks. When rounded by glacial action, smaller rock promontories may be referred to as rognons. The word is of Greenlandic origin and has been used in English since the 1870s. Description The term is typically used in areas where a permanent ice sheet is present and the nunataks protrude above the sheet.J. J. Zeeberg, ''Climate and Glacial History of the Novaya Zemlya Archipelago, Russian Arctic''. pp. 82–84 Nunataks present readily identifiable landmark reference points in glaciers or ice caps and are often named. While some nunataks are isolated, sometimes they form dense clusters, such as Queen Louise Land in Greenland. Nunataks are generally angular and jagged, which hampers the formation of glacial ice on their tops, although snow can a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microcline
Microcline (KAlSi3O8) is an important igneous rock-forming tectosilicate mineral. It is a potassium-rich alkali feldspar. Microcline typically contains minor amounts of sodium. It is common in granite and pegmatites. Microcline forms during slow cooling of orthoclase; it is more stable at lower temperatures than orthoclase. Sanidine is a polymorph of alkali feldspar stable at yet higher temperature. Microcline may be clear, white, pale-yellow, brick-red, or green; it is generally characterized by cross-hatch twinning that forms as a result of the transformation of monoclinic orthoclase into triclinic microcline. The chemical compound name is potassium aluminium silicate, and it is known as E number reference E555. Geology Microcline may be chemically the same as monoclinic orthoclase, but because it belongs to the triclinic crystal system, the prism angle is slightly less than right angles; hence the name "microcline" from the Greek "small slope." It is a fully ordered triclin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenocryst
300px, feldspathic phenocrysts. This granite, from the Switzerland">Swiss side of the Mont Blanc massif, has large white plagioclase phenocrysts, triclinic minerals that give trapezoid shapes when cut through). 1 euro coins, 1 euro coin (diameter 2.3 cm) for scale. A phenocryst is an early forming, relatively large and usually conspicuous crystal distinctly larger than the grains of the rock groundmass of an igneous rock. Such rocks that have a distinct difference in the size of the crystals are called porphyries, and the adjective porphyritic is used to describe them. Phenocrysts often have euhedral forms, either due to early growth within a magma, or by post-emplacement recrystallization. Normally the term ''phenocryst'' is not used unless the crystals are directly observable, which is sometimes stated as greater than .5 millimeter in diameter. Phenocrysts below this level, but still larger than the groundmass crystals, are termed ''microphenocrysts''. Very large phenocrysts a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Granodiorite
Granodiorite () is a coarse-grained (phaneritic) intrusive igneous rock similar to granite, but containing more plagioclase feldspar than orthoclase feldspar. The term banatite is sometimes used informally for various rocks ranging from granite to diorite, including granodiorite. Composition According to the QAPF diagram, granodiorite has a greater than 20% quartz by volume, and between 65% and 90% of the feldspar is plagioclase. A greater amount of plagioclase would designate the rock as tonalite. Granodiorite is felsic to intermediate in composition. It is the intrusive igneous equivalent of the extrusive igneous dacite. It contains a large amount of sodium (Na) and calcium (Ca) rich plagioclase, potassium feldspar, quartz, and minor amounts of muscovite mica as the lighter colored mineral components. Biotite and amphiboles often in the form of hornblende are more abundant in granodiorite than in granite, giving it a more distinct two-toned or overall darker appearan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sierra Nevada Batholith
The Sierra Nevada Batholith is a large batholith which forms the core of the Sierra Nevada mountain range in California, exposed at the surface as granite. The batholith is composed of many individual masses of rock called ''plutons'', which formed deep underground during separate episodes of magma intrusion, millions of years before the Sierra itself first began to rise. The extremely hot, relatively buoyant plutons, also called ''plutonic diapirs'', intruded through denser, native country rock and sediments, never reaching the surface. At the same time, some magma managed to reach the surface as volcanic lava flows, but most of it cooled and hardened below the surface and remained buried for millions of years. The batholith – the combined mass of subsurface plutons – became exposed as tectonic forces initiated the formation of the Basin and Range geologic province, including the Sierra Nevada. As the mountains rose, the forces of erosion eventually wore down the material ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intrusion
In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and compositions, illustrated by examples like the Palisades Sill of New York and New Jersey; the Henry Mountains of Utah; the Bushveld Igneous Complex of South Africa; Shiprock in New Mexico; the Ardnamurchan intrusion in Scotland; and the Sierra Nevada Batholith of California. Because the solid country rock into which magma intrudes is an excellent insulator, cooling of the magma is extremely slow, and intrusive igneous rock is coarse-grained (phaneritic). Intrusive igneous rocks are classified separately from extrusive igneous rocks, generally on the basis of their mineral content. The relative amounts of quartz, alkali feldspar, plagioclase, and feldspathoid is particularly important in classifying intrusive igneous rocks. Intrusions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cathedral Peak Granodiorite
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 (Tuolumne Batholith), 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 (Upper Cretaceous). Geographic situation The Cathedral Peak Granodiorite forms part of the central eastern Sierra Nevada in California. It is exposed in glaciated outcrops from the upper Yosemite Valley into the high Sierra Divide. It covers large parts of Mariposa County and Tuolumne County and also touches Madera County and Mono County. At its northern end it includes Tower Peak and Matterhorn Peak, at 12,264 feet (3743 m) its highest elevation. In its southwestern section rises the Cathedral Range with the 10,911 feet Cathedral Peak (3326 m) above Tuolumne Meadows. California ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
