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Johnson Granite Porphyry
Johnson Granite Porphyry is found in Tuolumne Meadows, Yosemite National Park. Johnson Granite Porphyry was named for Johnson Peak, the highest mountain in Tuolumne Meadows, Yosemite National Park. Its area is estimated at , the exposed area covering roughly .Glazner, Allen F, Stock, Greg M. (2010). ''Geology Underfoot in Yosemite''. Mountain Press, p. 53. . Johnson Granite Porphyry is part of the Tuolumne Batholith. Its boundaries are difficult to trace, and are irregular. It is both the youngest, and the most siliceous rock of Tuolumne Intrusive Suite. Geology The innermost, most felsic part of the Tuolumne Batholith is the Johnson Granite Porphyry. It is a highly irregular, elongated body. Completely surrounding it is the much larger body of Cathedral Peak granite. Field observations and magnetic fabrics suggest an extrusive event, that is, Johnson Granite Porphyry may record possible volcanism. This may relate to deformation along active shear zones. Johnson Granite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Year
A year is a unit of time based on how long it takes the Earth to orbit the Sun. In scientific use, the tropical year (approximately 365 Synodic day, solar days, 5 hours, 48 minutes, 45 seconds) and the sidereal year (about 20 minutes longer) are more exact. The modern calendar year, as reckoned according to the Gregorian calendar, approximates the tropical year by using a system of leap years. The term 'year' is also used to indicate other periods of roughly similar duration, such as the lunar year (a roughly 354-day cycle of twelve of the Moon's phasessee lunar calendar), as well as periods loosely associated with the calendar or astronomical year, such as the seasonal year, the fiscal year, the academic year, etc. Due to the Earth's axial tilt, the course of a year sees the passing of the seasons, marked by changes in weather, the hours of daylight, and, consequently, vegetation and soil fertility. In temperate and subpolar climate, subpolar regions around the planet, four ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
K-feldspar
Orthoclase, or orthoclase feldspar (endmember formula K Al Si3 O8), is an important tectosilicate mineral which forms igneous rock. The name is from the Ancient Greek for "straight fracture", because its two cleavage planes are at right angles to each other. It is a type of alkali feldspar, also known as potassium feldspar or K-spar. The gem known as moonstone (see below) is largely composed of orthoclase. Formation and subtypes left, Orthoclase Organ_Mountains.html" ;"title="crystal twinning from the Organ Mountains">crystal twinning from the Organ Mountains in New Mexico Orthoclase is a common constituent of most granites and other felsic igneous rocks and often forms huge crystals and masses in pegmatite. Typically, the pure potassium endmember of orthoclase forms a solid solution with albite, the sodium endmember (NaAlSi3O8) of plagioclase. While slowly cooling within the earth, sodium-rich albite lamellae form by exsolution, enriching the remaining orthoclase with p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Geology Of The Yosemite Area
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. Most of the rock now exposed in the park is granitic, having been formed 210 to 80 million years ago as igneous diapirs 6 miles (10 km) below the surface. Over time, most of the overlying rock was uplifted along with the rest of the Sierra Nevada and was removed from the area by erosion. This exposed t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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, metamorphic, and sedimentary 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 '' si .... References External links and references The Fine Gold Intrusive Suite: The roles of basement terranes and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
El Capitan Granite
El Capitan Granite is a type of granite (also see granodiorite), in a large area near El Capitan, in Yosemite National Park, California, United States. The granite forms part of the Tuolumne Intrusive Suite (also known as Tuolumne Batholith), one of the four major intrusive suites within the Sierra Nevada. El Capitan granite is mostly unjointed. Composition The granite has abundant quartz, plagioclase, crystals of orthoclase, and both feldspars — orthoclase and plagioclase — are white. Hornblende is rare, compared to other Yosemite granites. Most black minerals are biotite.Glazner, Allen F, Stock, Greg M. (2010). ''Geology Underfoot in Yosemite''. Mountain Press, p. 45. Location It is found west of Half Dome Granodiorite, both north and south, to a western limit near Cookie Cliffs. All of Turtleback Dome, El Capitan, The Three Brothers, and Cathedral Rocks are made of El Capitan Granite as is Elephant Rock. El Capitan Granite makes up most of the granite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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. Califor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Magnetite
Magnetite is a mineral and one of the main iron ores, with the chemical formula . It is one of the iron oxide, oxides of iron, and is ferrimagnetism, ferrimagnetic; it is attracted to a magnet and can be magnetization, magnetized to become a permanent magnet itself. With the exception of extremely rare native iron deposits, it is the most magnetic of all the naturally occurring minerals on Earth. Naturally magnetized pieces of magnetite, called lodestone, will attract small pieces of iron, which is how ancient peoples first discovered the property of magnetism. Magnetite is black or brownish-black with a metallic luster, has a Mohs scale of mineral hardness, Mohs hardness of 5–6 and leaves a black streak (mineralogy), streak. Small grains of magnetite are very common in igneous rocks, igneous and metamorphic rocks. The chemical IUPAC name is iron(II,III) oxide and the common chemical name is ''ferrous-ferric oxide''. Properties In addition to igneous rocks, magnetite als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Apatite
Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of Hydroxide, OH−, Fluoride, F− and Chloride, Cl− ion, respectively, in the crystal. The formula of the admixture of the three most common Endmember (mineralogy), endmembers is written as Calcium, Ca10(Phosphate, PO4)6(OH,F,Cl)2, and the crystal unit cell formulae of the individual minerals are written as Ca10(PO4)6(OH)2, Ca10(PO4)6F2 and Ca10(PO4)6Cl2. The mineral was named apatite by the German geologist Abraham Gottlob Werner in 1786, although the specific mineral he had described was reclassified as fluorapatite in 1860 by the German mineralogist Karl Friedrich August Rammelsberg. Apatite is often mistaken for other minerals. This tendency is reflected in the mineral's name, which is derived from the Greek word ἀπατάω (apatáō), which means ''to deceive''. Geology Apatite is very common as an accessory mineral in igneous and metamorphic roc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Allanite
Allanite (also called orthite) is a sorosilicate group of minerals within the broader epidote group that contain a significant amount of rare-earth elements. The mineral occurs mainly in metamorphosed clay-rich sediments and felsic igneous rocks. It has the general formula A2M3Si3O12 H where the A sites can contain large cations such as Ca2+, Sr2+, and rare-earth elements, and the M sites admit Al3+, Fe3+, Mn3+, Fe2+, or Mg2+ among others. However, a large amount of additional elements, including Th, U, Be, Zr, P, Ba, Cr and others may be present in the mineral. The International Mineralogical Association lists four minerals in the allanite group, each recognized as a unique mineral: allanite-(Ce), allanite-(La), allanite-(Nd), and allanite-(Y), depending on the dominant rare earth present: cerium, lanthanum, neodymium or yttrium. Allanite contains up to 20% rare-earth elements and is a valuable source of them. The inclusion of thorium and other radioactive elements in allanit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Sphene
Titanite, or sphene (), is a calcium titanium nesosilicate mineral, Ca Ti Si O5. Trace impurities of iron and aluminium are typically present. Also commonly present are rare earth metals including cerium and yttrium; calcium may be partly replaced by thorium. Nomenclature The International Mineralogical Association Commission on New Minerals and Mineral Names (CNMMN) adopted the name titanite and "discredited" the name sphene as of 1982, although commonly papers and books initially identify the mineral using both names. Sphene was the most commonly used name until the IMA decision, although both were well known. Some authorities think it is less confusing as the word is used to describe any chemical or crystal with oxidized titanium such as the rare earth titanate pyrochlores series and many of the minerals with the perovskite structure. The name sphene continues to be publishable in peer-reviewed scientific literature, e.g. a paper by Hayden et al. was published in early 2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Accessory Phases
Accessory may refer to: * Accessory (legal term), a person who assists a criminal In anatomy * Accessory bone * Accessory breast * Accessory kidney * Accessory muscle * Accessory nucleus, in anatomy, a cranial nerve nucleus * Accessory nerve * Accessory spleen In arts and entertainment * Accessory (band), with members Dirk Steyer and Ivo Lottig * Video game accessory, a piece of hardware used in conjunction with a video game console for playing video games * ''Accessories'' (album), a compilation album from Dutch alternative rock band The Gathering * Accessory, a type of rulebook in ''Dungeons & Dragons'' and other role-playing games Other uses * Fashion accessory, an item used to complement a fashion or style * Accessory suite, a secondary dwelling on a parcel of land * Rental accessories and attachments, accessories used in the rental industry * Cable accessories for connecting and terminating cables * Accessory fruit, in which some of the flesh is derived from tissues other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Mafic Mineral
A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include basalt, diabase and gabbro. Mafic rocks often also contain calcium-rich varieties of plagioclase feldspar. Mafic materials can also be described as ferromagnesian. History The term ''mafic'' is a portmanteau of "magnesium" and "ferric" and was coined by Charles Whitman Cross, Joseph P. Iddings, Louis V. Pirsson, and Henry Stephens Washington in 1912. Cross' group had previously divided the major rock-forming minerals found in igneous rocks into ''salic'' minerals, such as quartz, feldspars, or feldspathoids, and ''femic'' minerals, such as olivine and pyroxene. However, micas and aluminium-rich amphiboles were excluded, while some calcium minerals containing little iron or magnesium, such as wollastonite or apatite, were included in the f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
