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where is anorthosite found

Anorthosite is a phaneritic, intrusive igneous rock which is characterized by a predominance of plagioclase feldspar which is almost 90–100%, and a minimal mafic component. This is because Anorthite weathers rapidly to clay minerals under atmospheric conditions. Although these large masses are generally supposed to provide the best sample of the deep lithosphere (the outer shell of the Earth), they often appear to be floored over most of their outcrop area. Hudson Resources has … Anorthosite. The Morin Anorthosite in the same area occupies 2,600 square km (1,040 square miles), and the Adirondack Anorthosite is exposed over an area of about 3,900 square km (1,560 square miles). Mapped onto the Pangaean continental configuration of that eon, these occurrences are all contained in a single straight belt, and must all have been emplaced intracratonally. 4 ). Several pure anorthosite clasts have been found in the Dhofar samples, and 60015 is an anorthosite with high abundance of plagioclase and uniform composition in comparison with other FAN samples. This stuff is easy to mine. Shallow refraction work in the field was combined with high pressure laboratory experiments in order to investigate the effects of mylonitization as a control on seismic velocity anisotropy. Anorthosite forms deep underground, and in dikes and intrusions; it makes up about 60% of the Earth's crust. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. The Bushveld Complex underlies an area of about 50,000 square km (20,000 square miles); and the Great Dyke of Zimbabwe, another layered complex, has been traced for more than 480 km (300 miles). Some of the rocks in both the maria and the…. Large masses of anorthosite, however, do occur and can be found in such locations as the New England region of the United States, Zimbabwe, and Canada. Occurrences of Proterozoic anorthosites are commonly referred to as 'massifs'. The company had been working on its rare earth and found a large anorthosite body. The topic Anorthosite represents a specific aggregation or gathering of resources found in Colby College Libraries. However, the details of this process are still hotly debated. Major occurrences of Proterozoic anorthosite are found in the southwest U.S., the Appalachian Mountains, eastern Canada, across southern Scandinavia and eastern Europe. Anorthosite is considerably less abundant than either basalt or granite, but the complexes in which it occurs are, nevertheless, often of immense size. Our editors will review what you’ve submitted and determine whether to revise the article. Britannica Kids Holiday Bundle! All anorthosites found on Earth consist of coarse crystals, but some samples of the rock taken from the Moon are finely crystalline. Essential minerals - these are minerals that are required within the classification of this rock: Non-essential minerals - these minerals are common, sometimes major components, but are not always present: Current server date and time: November 30, 2020 23:24:37 • It has been derived from a basic magma either grabbroic or dioritic in compsition. Major occurrences of Proterozoic anorthosite are found in the southwest U.S., the Appalachian Mountains, eastern Canada, across southern Scandinavia and eastern Europe. The Canadian anorthosites are thought to be laccolithic, while the Adirondack Anorthosite is considered a floored sheet. Little correlation can be made with rocks of Mesozoic-Cenozoic age because few modern orogenic…, kinds are basalts and anorthosites. This white rock is composed almost entirely of crystals of one mineral, feldspar. Page generated: October 13, 2020 06:23:16, Lucky mine, Orogrande District, Otero Co., New Mexico, USA, Ashland Black Granite Quarry, Ashland Co., Wisconsin, USA. Hudson Resources has proven it can reduce the anorthosite's iron content by running it through the company's onsite magnetic separator. Lunar anorthosite is believed to be the result of a gravitational differentiation. Anorthite is rare on the Earth but abundant on the Moon. We have provided you with all information about Anorthosite rock here. Anorthite is very rare on Earth, but abundant in moon rocks. Oxides, mostly magnetite or ilmenite, are also common. This clast is especially interesting as it has one of the best-preserved igneous textures of any lunar anorthosite (see photo below), and it was found in a type of breccia collected around North Ray crater in which ancient crustal rocks have been found by Chantal Alibert, Malcolm McCulloch, and myself in a previous study back in 1994. Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... Large outcrop of anorthosite in the Helleren massif, Jibbeheia, Rogaland, Nor. The Whitestone anorthosite can be found in both the undeformed and mylonitic states. Feldspar is a very common mineral and occurs in virtually all igneous rocks, but rocks containing 90%+ calcium feldspar are less common. Get to know all the Anorthosite Uses. Olivine, amphibole, ilmenite, magnetite, and spinel are also sometimes present. This ancient crust has been smashed and redistributed by countless meteoric impacts. A particularly large and well-known series of anorthosite complexes occurs in the Adirondack Mountains and … They usually occur as laccoliths (low domelike intrusions with a flat base found between sedimentary beds), lopoliths (laccoliths with basin-shaped bases), or sills … A spectacular example of this type occurs in the Gardar Igneous Province near the southern tip of Greenland, where basaltic to trachytic dikes contain thousands of anorthosite inclusions in varying states of concentration and disaggregation. You do a little blasting, a little digging. Plagioclase compositions in the anorthosites (An 58-65) match those in their host dike rocks. The anorthosite occurs as a scull-cap on the mountain north of the borderland between the two pre-Cambrian complexes, the late 1.9 Ga … Anorthosite (pronunciation: / æ n ˈ ɔːr θ ə s aɪ t /) is a phaneritic, intrusive igneous rock characterized by a predominance of plagioclase feldspar (90–100%), and a minimal mafic component (0–10%). Massif-type anorthosites occur in Proterozoic rocks on all continents (Anderson, 1969; Ashwal, 1993), but in northeastern North America are concentrated in a belt stretching from the Adirondack Mountains in New York northeast through Quebec to the coast of Labrador (Fig. "A majority of the lunar surface is made up of rocks similar to the Shawmere Anorthosite, found near Foleyet. This stuff is easy to mine. Consequently, at least three geochemical end-members are required to explain the lunar anorthositic plagioclase REE variations, consistent with the geochemical fields observed in REE plots ( Fig. You do a little blasting, a little digging. White Mountain with 1300 m height, the Greenlandic name is ‘Qaqortorsuaq’ (i.e. These anorthosite samples are thought to be identified as pure anorthosite rocks composed of high abundances of igneous plagioclase (>98% plagioclase) or metamorphosed anorthosite from such … The mafic mineral may be clinopyroxene, orthopyroxene, olivine, or, more rarely, amphibole. Omissions? One explanation for the presence of anorthosite in the lunar crust is based on the assumption that the Moon was once molten. Anorthosite is in section 10 of the QAPF diagram. a granular plutonic rock composed largely of labradorite or a more calcic feldspar. As noted in the caption of Figure D, this anorthosite was found on the south shore of Lake Erie, many kilometers/miles from any recorded bedrock occurrences of anorthosite. Anorthosite is also found on the lunar surface. • It contain plagioclase of An35-65 range. Mapped onto the Pangaean continental configuration of that eon, these occurrences are all contained in a single straight belt, and must all have been emplaced intracratonally. They usually occur as laccoliths (low domelike intrusions with a flat base found between sedimentary beds), lopoliths (laccoliths with basin-shaped bases), or sills (tabular intrusions between other rocks). Anorthosite was found in all the rocks returned from the Moon , including the oldest (dating back 4.4 to 4.5 billion years), and is believed to make up a significant fraction of the lunar crust. The lunar basalts, relatively rich in iron and many also in titanium, are found in the maria. This stuff is easy to mine. The soda content is averaging 2.3%. From Stone Age, rocks are used for various purposes. The thickness of the Sudbury Lopolith is estimated at 3 km (1.9 miles), that of the Bushveld at 5 km (3 miles). For instance, about 155,000 square km (60,000 square miles) of eastern Canada is underlain by anorthosite, the Saguenay Mass alone accounting for a tenth of this. Corrections? The company had been working on its rare earth and found a large anorthosite body. Anorthosite dikes (slablike, steeply inclined intrusions along fissures) are very rare, and effusive equivalents of anorthosite are unknown. Massif anorthosite • Layring is not found in massif anorthosite. the big white), was observed in 1946 during fieldworkcarried out by the Geological Survey of Greenland on the west coast of Greenland. Although these large masses are generally supposed to provide the best sample of the deep lithosphere (the outer shell of the Earth), they often appear to be floored over most of their outcrop area. This article was most recently revised and updated by, https://www.britannica.com/science/anorthosite, Central Michigan University - Anorthosite. [1860 65; < F anorthose anorthoclase (an AN 1 + Gk orthós straight) + ITE1] * * * Type of A few people raised questions about how the new-found H2O in the lunar mantle would change our models of anorthosite formation. In the highlands the rocks are largely anorthosites, which are relatively rich in aluminum, calcium, and silicon. Importantly, large volumes of ultramafic rocks are not found in association with Proterozoic anorthosites. The ancient crust of the Moon is believed to have been composed of the rock, anorthosite, a calcium-rich white rock. Let us know if you have suggestions to improve this article (requires login). 14. You do a little blasting, a little digging. The lunar highlands are … Updates? westside turnout of Baughman Spring's, is an exposure of white-colored anorthosite, a rock 1220 million years old, which is also found on the lunar highlands Gabronite (706 words) [view diff] exact match in snippet view article find links to article Anorthosite is also found on the lunar surface. Oxides, mostly magnetite or ilmenite, are also common. Rocks like this make up much of the Highlands of the Moon, where feldspar produces the light color. NOW 50% OFF! Good crystals have been found in lava-digested limestone blocks erupted from Mount Vesuvius. Anorthosite Anorthosite: Anorthosite: A leucocratic coarse-grained plutonic rock consisting essentially of plagioclase (usually labradorite or bytownite) often with small amounts of pyroxene. Anorthite is found in mafic igneous rocks. A coarse-grained crystalline rock consisting mostly of calcic plagioclase (>90%, usually labradorite) with <10% mafics. Generally, anorthosite occurrences in Greenland are structurally deformed and heavily metamorphosed which complicates revealing their genetic relationships. /an awr theuh suyt /, n. Petrol. Plagioclase is lighter than most other minerals found there and therefore rose to the uppermost part of the magma ocean. Mapped onto the Pangaean continental configuration of that eon, these occurrences are all contained in a single straight belt, and must all have been emplaced intracratonally. This section is currently hidden. ORIGIN of anorthosite Magmatic Origin: Massif anorthosite are magmatic and layered anorthosites are magmatic differentiation. Also, the issue of how the very pure anorthosite (with scarce mafic minerals) widely observed across the Moon is formed was also discussed. Andesite is a fine-grained igneous rock that forms when the magma is erupted onto the surface and is crystallized quickly. Shortly after material gathered together to form the Moon, the outer Moon melted. Origin of Anorthosite. …a marked similarity in the anorthosites in various belts throughout the world, and their similar relationship with the gneisses suggests that the belts have undergone comparable stages of evolution, although each has its own distinctive features. It seems likely that the cobbles and pebbles represent pieces of rock that were glacially transported from one or more of the anorthosite massifs of the Grenville Province north and northwest of Montreal, Québec, Canada. Also, the metals and minerals found in rock play an important role in our life. The mafic mineral may be clinopyroxene, orthopyroxene, olivine, or, more rarely, amphibole. anorthositic /an aw theuh sit ik/, adj. Click the. That is, the lunar anorthosite plagioclase REE compositions define a 2-dimensional dataset. However, there is some question as to what name would best describe any occurrence of anorthosite together with the rock types mentioned above. Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. The term anorthosite, from Frenc anorthose (term for plagioclase) was coined by Sterry Hunt. Major occurrences of Proterozoic anorthosite are found in the southwest U.S., the Appalachian Mountains, eastern Canada, across southern Scandinavia and eastern Europe. The company had been working on its rare earth and found a large anorthosite body. Strictly speaking, the name “anorthosite” is applied to a rock composed of 90 to 100 of calcium-rich plagioclase feldspar and small amounts of high temperature minerals like pyroxene, olivine, magnetite (Fe3O4) or ilmenite (FeTiO3). 1). Anorthosite, type of intrusive igneous rock composed predominantly of calcium-rich plagioclase feldspar. Most anorthosites formed during Precambrian times. Courtesy of Hudson Resources L arge deposits of pure, highly calcic anorthosite have only been discovered in two places in the known universe: Hudson Resources’ White …

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