CaO values can be influenced by scapolite alteration or contamination by thin calcite veins (Morrison and Valley, 1991). The leucogabbros display large variations in trace-element concentrations, ranging from low concentrations similar to anorthosite in less mafic varieties to higher concentrations similar to gabbros in more mafic varieties.

The former rocks of this study are located in the southern part of TIB, in the late Olle Wallner, who without complaints prepared an endless row of thin sections. model for the origin of the gabbro-anorthosite-syenite-potassic granite suite.

Small “clumps” of mafic minerals are in the hand specimen, but these are not represented in the thin sections. The composition of this rock is given in table 6. The age of this rock is 4440 million years. Olivine - Trace olivine Fo 65-67 is found with low-Ca pyroxene in “mafic clumps.” Anorthosite This white rock is composed almost entirely of crystals of one mineral, feldspar. Rocks like this make up much of the Highlands of the Moon, where feldspar produces the light color. Shortly after material gathered together to form the Moon, the outer Moon melted.

Anorthosite thin section

Anorthite is the calcic end member of the plagioclase feldspar series. In thin section, plagioclase feldspar grains often look like they’re sprinkled with dirt (PPL) or tiny confetti (XPL). You can find the explanation on the plagioclase feldspar page. 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.

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ORIGIN of anorthosite Magmatic Origin: Massif anorthosite are magmatic and layered anorthosites are magmatic differentiation. • It has been derived from a basic magma either grabbroic or … Anorthosite is a rock type of the mafic-ultramafic succession, The thin section above doesn't allow evaluation of textures that may be related to overgrowths.

Anorthosite is an almost monomineralic, feldspathic rock with a great variety of industrial applications (Table 1). Anorthosite massifs are known to host important ore depos-its such as ilmenite and are, in many cases, excellent sources for high-quality rock aggregate and also for dimension-stone. The exploitation of anorthosite for industrial

[ RIGHT ] Microscope image in linear polarized light of a thin-section showing a spinel-rich clast in lunar meteorite ALHA81005. The Bethampudi layered anorthosite complex at the border zone of Archaean supracrustal rocks of Khammam district, Eastern Ghats shows normal stratification predominantly in the form of rhythmic layering and often exhibits of zebra layering. Graded bedding and cumulate structures are also noticed. The rocks of the study area are classified based on petrography into anorthositic rocks, gabbroic This file is licensed under the Creative Commons Attribution 2.0 Generic license.: You are free: to share – to copy, distribute and transmit the work; to remix – to adapt the work; Under the following conditions: attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that Find the perfect anorthosite stock photo. Huge collection, amazing choice, 100+ million high quality, affordable RF and RM images.

These are photomicrographs - very thin slices of rock, seen in plane-polarised light, Merensky Reef, and the remaining eight from the mottled anorthosite forming the footwall to the. Bastard Reef. Magnetite is found in the majority of thin sections 16 - Mineralienatlas (Deutsch) 17 - Online Mineral Museum 18 - QUT Mineral Atlas 19 - Ruff.Info 20 - UCLA - Petrography Thin-Sections 21 - WWW- MINCRYST. plagioclase megacrysts from the Chugwater anorthosite yields a baddeleyite age of 1435.4.
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This sample was collected from a Part of the Hypersthene gabbro at Sanna Point. CaO values can be influenced by scapolite alteration or contamination by thin calcite veins (Morrison and Valley, 1991).

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Jan 19, 2017 - Photomicrograph of a thin section showing twinned, aligned plagioclase in anorthosite. A coarse grained igneous rock, anorthosite is

Olivine: Warren and Wasson (1977), Ryder (1982) and James et al. (1991) find that olivine in various portions of 60025 has a range of compositions (Fo 42-66). Pyroxene: Pyroxene is present as subhedral to anhedral grains included in plagioclase, as anhedral grains at 2019-06-03 · One distinctive feature of some komatiites is spinifex texture, in which the rock is crisscrossed with long, thin olivine crystals. Spinifex texture is commonly said to result from extremely fast cooling, but recent research points instead to a steep thermal gradient, in which olivine conducts heat so rapidly that its crystals grow as wide, thin plates instead of its preferred stubby habit.

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The microscopic examination of thin-sections in the petrographic analysis also provides important grain size, textural Quartz monzogabbro. Quartz anorthosite.

No need to register, buy now! Grenville Province anorthosite massifs were derived from depleted mantle. It is not clear whether massifs and related mafic intrusions throughout the Nain Province of Labrador were derived from enriched mantle, or were contaminated by early Archean (greater than 3500 Ma) silicic crustal materials, heretofore thought to be restricted to coastal Labrador. Anorthosite Thin Sections (cont.) 2.2 Secondary Minerals Quartz.

Anorthosite. Calciclasite ⓘ Labradoritite ⓘ Anorthitite ⓘ Foid-bearing-anorthosite ⓘ Troctolitic anorthosite ⓘ Charnockitic anorthosite; Foid-syenitoid. Foid-monzosyenite. Nepheline-monzosyenite ⓘ Allochetite; Leucite-monzosyenite ⓘ Sommaite; Foid-gabbroid. Foid-gabbro. Analcime-gabbro ⓘ Glenmuirite ⓘ Teschenite; Nepheline-gabbro ⓘ Theralite

Famous for its complete ring dyke made of Eucrite, a similar gabbro. This sample was collected from a Part of the Hypersthene gabbro at Sanna Point. CaO values can be influenced by scapolite alteration or contamination by thin calcite veins (Morrison and Valley, 1991). The leucogabbros display large variations in trace-element concentrations, ranging from low concentrations similar to anorthosite in less mafic varieties to higher concentrations similar to gabbros in more mafic varieties. 11 clasts and studied thin sections of them.

Microscopic examination of a thin section of garnet anorthosite from the former locality showed it to consist predominantly of scapolitised plagioclase; large (2 - 9mm) garnets, altered to kelyphite on their margins; and minor clinopyroxene, hornblende and magnetite-ilmenite. Origin of Anorthosite by Textural Coarsening: Quantitative Measurements of a Natural Sequence of Textural Development MICHAEL D. HIGGINS* SCIENCES DE LA TERRE, UNIVERSITE´ DU QUE´BEC A` CHICOUTIMI, CHICOUTIMI, G7H 2B1, CANADA Thin section of an olivine oikocryst adjacent to section … 2013-10-27 Jan 19, 2017 - Photomicrograph of a thin section showing twinned, aligned plagioclase in anorthosite.