In most of this anorthosite, andesine megacrysts with bytownite inclusions are embedded in a ghost-like, earlier fine-grained texture. Extinction contrast of the

The textures of plagioclase crystals within large olivine oikocrysts preserve the sequence of the formation of anorthosite. Such textures have been quantified in a troctolite–anorthosite from the Proterozoic Lac-St-Jean anorthosite complex, Canada.

Anorthosite, type of intrusive igneous rock composed predominantly of calcium-rich plagioclase feldspar. All anorthosites found on Earth consist of coarse crystals, but some samples of the rock taken from the Moon are finely crystalline. Most anorthosites formed during Precambrian times. Ashwal (1993) listed six major types or anorthosite occurrences: 1. Archean anorthosite plutons 2.

An information card with details on the rock formation, mineral content, characteristics, and uses is included. Typical samples sizes are generally 1-2 inches in length or width but can vary based on availability and natural formation. Abstract. Lunar anorthosite 15415 consists almost entirely of anorthite (homogeneous anorthite 96.6 molecule percent), with accessory diopsidic augite and traces of hypersthene, ilmenite, and a The dominant texture is ‘Nodular’ troctolite, in which amoeboid olivine oikocrysts 10–20 cm in diameter are spaced 20–30 cm apart within a matrix of anorthosite ( Woussen et al., 1988; Figs 1 and 2 ).

1980-01-01 · Small-scale ductile shear zones belonging to several sets in orientation and sense of movement, and including both continuous and discontinuous strain, modify an older granulite facies mineralogy and equilibrium textures of the meta-anorthosite and produce a new schistosity, textures and parageneses. The textures of plagioclase crystals within large olivine oikocrysts preserve the sequence of the formation of anorthosite. Such textures have been quantified in a troctolite–anorthosite from the Proterozoic Lac-St-Jean anorthosite complex, Canada.

2004-05-01

Cumulate rocks typically have the same minerals about the same size. 2014-09-10 Quantitative Texture Analysis of an Anorthosite— Application to Thermal Expansion, Young's Modulus and Thermal Stresses.pdf Available via license: CC BY 3.0 Content may be subject to copyright. 2591.13 Mottled anorthosite, mottles increasing in size and frequency downwards.

1972-01-28

Apr 23, 2013 Copper and nickel are two metals modern society cannot get enough of, but there is not enough to go around, says Rick Mills, publisher of Ahead Aug 23, 2019 Igneous textures and composition are variable at the mesoscale, and due to the scarcity of meter-scale structural mapping across much of the Sep 8, 2020 the radial texture) reflected the change in the undercooling state of the magma. Based on the petrography of the anorthosite and lava flows, the Mar 11, 2015 Most igneous rocks have a crystalline texture, but some are clastic, vesicular, frothy, or glassy. Anorthosite is an scarce, coarsely-crystalline, Schrijver (1968) for the Morin anorthosite and proposed that Adirondack anorthosites were Coarse comb texture is visible along the dike's margins. Proceed Anorthosite /ænˈɔːrθəsaɪt/ is a phaneritic, intrusive igneous rock characterized by its composition: mostly plagioclase feldspar, with a minimal mafic component. Pyroxene, ilmenite, magnetite, and olivine are the mafic minerals most commonly present.

top of Fe, Mg, and Ca. Basalt is the aphanitic (fine-textured) extrusive equivalent of gabbro. top Archean anorthosite complexes in the Superior Province are listed in Table 1.
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1 of the KIC. Cumulate textures are relatively widespread on a Lens-shaped aggre- gates of mafic minerals, up to 10 cm in size, commonly appear as well developed corona textures.

Stillwater Complex, Montana. Plane/cross-polarized light, field width is 6 mm.
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TEXTURE • Anorthosite are leucocratic, coarse grained and hypidiomorphic. Some crystals have euhedral form, some have poorly developed faces and others have no crystal form at all. 4.

10 Feb 1993 or neutron texture goniometry), crystal and spechnen sy•mnetry; but petrofabric data can be used to provide vital information about.