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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] |
Fine Gold Intrusive Suite
The Fine Gold Intrusive Suite is one of several intrusive suites that crosses into Yosemite National Park. These also include # Intrusive Suite of Buena Vista Crest # 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 Fine Gold Intrusive Suite is an intrusive suite which is massive (more than 3100 square kilometers) and long-lived (ca. 19 million years). Where is intrudes The Fine Gold Intrusive Suite intrudes both accreted oceanic terranes, and/or island-arc terranes, and, also continental crust Continental crust is the layer of igneous, sedimentary, and metamorphic rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called ''sial'' be .... References External links and references The Fine Gold Intrusive Suite: The roles of basement terranes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yosemite 20 Bg 090404
Yosemite National Park ( ) is an American national park in California, surrounded on the southeast by Sierra National Forest and on the northwest by Stanislaus National Forest. The park is managed by the National Park Service and covers an area of and sits in four countiescentered in Tuolumne and Mariposa, extending north and east to Mono and south to Madera County. Designated a World Heritage Site in 1984, Yosemite is internationally recognized for its granite cliffs, waterfalls, clear streams, giant sequoia groves, lakes, mountains, meadows, glaciers, and biological diversity. Almost 95 percent of the park is designated wilderness. Yosemite is one of the largest and least fragmented habitat blocks in the Sierra Nevada, and the park supports a diversity of plants and animals. The geology of the Yosemite area is characterized by granite rocks and remnants of older rock. About 10 million years ago, the Sierra Nevada was uplifted and tilted to form its unique slopes, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Farallon Plate
The Farallon Plate was an ancient oceanic plate. It formed one of the three main plates of Panthalassa, alongside the Phoenix Plate and Izanagi Plate, which were connected by a triple junction. The Farallon Plate began subducting under the west coast of the North American Plate—then located in modern Utah—as Pangaea broke apart and after the formation of the Pacific Plate at the centre of the triple junction during the Early Jurassic. It is named for the Farallon Islands, which are located just west of San Francisco, California. Over time, the central part of the Farallon Plate was completely subducted under the southwestern part of the North American Plate. The remains of the Farallon Plate are the Juan de Fuca, Explorer and Gorda Plates, subducting under the northern part of the North American Plate; the Cocos Plate subducting under Central America; and the Nazca Plate subducting under the South American Plate. The Farallon Plate is also responsible for transporting old i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sentinel Granodiorite
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.Structure of the Sentinel Granodiorite, Yosemite National Park, California – Books on Google Playhttps://play.google.com/store/books/details/Joseph_M_Petsche_Structure_of_the_Sentinel_Granodi?id=OWfrbPb8hikC accessdate: March 19, 2017 Its name Sentinel granodiorite was named after Sentinel Rock in Yosemite National Park, California.USGS: Geological Survey Professional Paper 160 (The Granitic Rocks of the Yosemite Region)less uniform in composition than most of the other intrusive bodies. In the western part of the zone crossed by the Yosemite Valley this rock is relatively light-colored and homogeneous; the eastern part is much more streaky and uneven in composition and texture an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuolumne Intrusive Suite
The Tuolumne Intrusive Suite 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 # Intrusive Suite of Yosemite Valley The age and composition of the Tuolumne Intrusive Suite 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, is the most extensive intrusive suite in the Park. It contains rock types including Half Dome Granodiorite and Cathedral Peak Granite, also, Kuna Crest Granodiorite. Oldest to youngest rocks are # Kuna Crest Granodiorite, # Half Dome Granodiorite, # Cathedral Peak Granodiorite (which is about 86 million years old), to # Johnson Granite Porphyry. The youngest, smallest, and most central rock body is of the Johnson Granite Porphyry, a variet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sierran Arc
In early Triassic time, an extensive volcanic arc system called the Sierran Arc began to develop along the western margin of the North American continent. In Southern California, this volcanic arc would develop throughout the Mesozoic Era to become the geologic regions known as the Sierra Nevada Batholith, the Peninsular Ranges Batholith, (in the Peninsular Ranges), and other plutonic and volcanic centers throughout the greater Mojave Desert region. Geology These massive belts of plutonic (intrusive) and volcanic (extrusive) regional belts and isolated centers developed as plate convergence and subduction took place farther west along the western continental margin. These igneous provinces shed vast quantities of sediment both eastward into the Western Interior Seaway and westward into Pacific margin basin. At the same time, older sedimentary materials and rocks were subjected to regional metamorphism throughout much of Baja and Southern California. In the region today, granitic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sierra Nevada–Great Valley Block
The Sierra Nevada–Great Valley Block (SNGV) is a section of the earth's crust in California encompassing most of the region east of the Great Valley fault system which runs along the eastern foot of the Coast Ranges, and west of the Sierra Nevada Fault which runs along the foot of the Sierra Nevada's eastern scarp. To the south, the block is bounded by the Garlock Fault. The northern bound is not well defined at present, but generally runs along a line extending across the northern Sacramento Valley. The SNGV has been found to behave like a rigid body relative to the North American Plate to which it is somewhat loosely attached, for this reason it is sometimes referred to as Sierra Nevada microplate. The block moves in a northwest direction at approximately 12 mm per year while the rest of the North American Plate is moving in a southwest direction. In far northern California, this produces a zone of convergence which has resulted in the compressive uplift of the Coast Ranges. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bald Rock, California
Bald Rock is a granite summit located in Butte County, California, in the Plumas National Forest. Located close to Lake Oroville, the dome peak overlooks Sacramento Valley and coastal mountain ranges. History The area was once home to the Maidu, a tribe of indigenous people. They left the rock with many unique features, such as, metate, grinding holes used to prepare acorns and grains. Recreation A short trail leads through the woods to the rock, which includes several crevasses and peculiar rock formations. The area is used for hiking, climbing, and rappeling. Camping is allowed but not closer than 300 yards from running water. The site also includes the ruin of a small shelter made from stacked rocks. Fauna The area is home to several animal species, including snakes, deer, mountain lion, and black bear Black bear or Blackbear may refer to: Animals * American black bear (''Ursus americanus''), a North American bear species * Asian black bear (''Ursus thibetanus''), a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Timeline Of Western North America
A timeline of significant geological events in the evolution of Western North America Western North America is the western edge of the North American continent that borders the Pacific Ocean. It consists of Alaska at the farthest north, down through the western Canadian province of British Columbia, the western U.S. states of Wa .... Dates are approximate. ("Ma" = millions of years ago) External links Geologic History of California: A Brief Overview by Joel Michaelsen {{DEFAULTSORT:Geologic Timeline Of Western North America Geology timelines North America geology-related lists Timelines of North American history Natural history of North America Geology of California Western United States ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erosion
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distinct from weathering which involves no movement. Removal of rock or soil as clastic sediment is referred to as ''physical'' or ''mechanical'' erosion; this contrasts with ''chemical'' erosion, where soil or rock material is removed from an area by dissolution. Eroded sediment or solutes may be transported just a few millimetres, or for thousands of kilometres. Agents of erosion include rainfall; bedrock wear in rivers; coastal erosion by the sea and waves; glacial plucking, abrasion, and scour; areal flooding; wind abrasion; groundwater processes; and mass movement processes in steep landscapes like landslides and debris flows. The rates at which such processes act control how fast a surface is eroded. Typically, physical erosion procee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now- extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pluton
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] |
