Anorthosite is an intrusive igneous rock characterized by its composition: mostly plagioclase feldspar (90–100%), with a minimal mafic component (0–10%).

IGSN, Sample Type, Notes, Location, Number Thin Sections, Storage Location. GRD02YCS0, Microcline, Microcline var. Amazonite, Colorado, 0, Ritter 154,

O. 3) yielded only 4 of pure plagioclase [9]. Of 100 Andesite. Andesite is an extrusive igneous rock that is higher in silica than basalt and lower than … 2013-04-23 Anorthosite plutons occur in a wide range of sizes. Some smaller plutons, exemplified by many anorthosite bodies in the U.S. and Harris in Scotland, cover only a few dozen square kilometres.

It is then mounted on a glass slide and then ground smooth using … 2009-09-01 Anorthosite rock thin section 2018-04-27 Anorthosite. Calciclasite ⓘ Labradoritite ⓘ Anorthitite ⓘ Foid-bearing-anorthosite ⓘ Troctolitic anorthosite ⓘ Charnockitic anorthosite; Foid-syenitoid. Foid-monzosyenite. Nepheline-monzosyenite … This is a thin section of one of a series of specimens very kindly sent to me from USA. Many thanks to the donor! This has come from an area dominated geologically by a large pre-cambrian anorthosite intrusion. Rounded-granular plagioclase and quartz with areas of intergrowth, with pink embayed garnet.

9, map and sections A–B, E–F). The monzonite and ferrodiorite were already solidified before the intrusion of troctolite and were recrystallized in a narrow

6. BRECCIA volcanic light grey CO. 7.

17 Feb 2013 the lunar surface2–4 and in volcanic rocks5–9 and regolith10. Part estimation) and after the heating experiment (lower thin curve) at the.

Accessory minerals present include ilmenite, chromite and olivine. Anorthosite: Anorthosite: A leucocratic coarse-grained plutonic rock consisting essentially of plagioclase (usually labradorite or bytownite) often with small amounts of pyroxene. Olivine, amphibole, ilmenite, magnetite, and spinel are also sometimes present. The term anorthosite, from Frenc anorthose (term for plagioclase) was coined by Sterry Hunt. Many anorthosite outcrops are transected by thin veins and stringers of quartz and feldspar, manifesting incipient disaggregation by the granitic protolith to the host quartzofeldspathic gneiss. This advances to the situation where clusters of individual plagioclase megacrysts, some with adhering mafic intercumulus, are strewn throughout the enclosing quartzofeldspathic gneiss (e.g., Fig. 18.8A ).

Some smaller plutons, exemplified by many anorthosite bodies in the U.S. and Harris in Scotland, cover only a few dozen square kilometres. Larger plutons, like the Mt. Lister Anorthosite, in northern orites mention clasts of anorthosite, but pyroxene- and olivine-bearing feldspathic lithologies such as impact-melt breccias, granulitic breccias, norites, and troctolites are mentioned just as frequently. Our own study of the 98 largest clasts in a thin section of Shişr 161 (25.2% Al. 2. O. 3) yielded only 4 of pure plagioclase [9]. Of 100 Andesite.
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Anorthite weathers quite readily, so it’s not terribly abundant on Earth. Unfortunately, these thin sections are thicker than the usual 30 micrometers, and in crossed polarizers (XPL) the plagioclase has colors of the upper first order, instead of the usual grey. The QAPF diagram ( see on this page ) shows that anorthosite has more than 90% plagioclase (P) compared to K-feldspar (or alkali feldspar, A), less than 5% quartz (Q) and less 5% feldspathoids (F). 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.

A coarse grained igneous rock, anorthosite is characterized by being … Proterozoic anorthosite Age. Proterozoic anorthosites were emplaced during the Proterozoic Eon (ca. 2,500–542 Ma).. Mode of occurrence. Anorthosite plutons occur in a wide range of sizes.
Ericsson 1995

Anorthosite; Norite, feldspathic pyroxenites; Harzburgite, Dunite (ultramafic in thin section; It may occur as independent prisms or as crusts on the pyroxene. 14.

Mylonit. Kolhaltiga peloider.

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HIGGINS TEXTURAL COARSENING OF ANORTHOSITE Fig. 1. Schematic diagram of the relationships of the three principal lithologies of anorthosite and troctolite. The section is ~1 m thick, but the horizontal scale is not linear. To the left the Nodular Troctolite consists of olivine oikocrysts 20–30 cm long (pale) set in a matrix of anorthosite

A thin sliver of rock is cut from the sample with a diamond saw and ground optically flat. It is then mounted on a glass slide and then ground smooth using … 2009-09-01 Anorthosite rock thin section 2018-04-27 Anorthosite. Calciclasite ⓘ Labradoritite ⓘ Anorthitite ⓘ Foid-bearing-anorthosite ⓘ Troctolitic anorthosite ⓘ Charnockitic anorthosite; Foid-syenitoid. Foid-monzosyenite.

In optical mineralogy and petrography, a thin section is a laboratory preparation of a rock, mineral, soil, pottery, bones, or even metal sample for use with a polarizing petrographic microscope, electron microscope and electron microprobe. A thin sliver of rock is cut from the sample with a diamond saw and ground optically flat. It is then mounted on a glass slide and then ground smooth using progressively finer abrasive grit until the sample is only 30 μm thick. The method uses the Michel

The properties of the main rock-forming minerals as seen There are video clips showing the optical properties of minerals in six rock thin sections. The thin sections, covering a range of igneous, metamorphic and Anorthosite is an intrusive igneous rock characterized by its composition: mostly plagioclase feldspar (90–100%), with a minimal mafic component (0–10%). The Buehler PetroThin is a thin section machine designed for sectioning a variety of samples. Our precision thin section machines come with a diamond cutting thin-sections were also examined using scanning electron situ analysis in thin-section, zircon grains were first iden- anorthosite complex, southern India. Modal analyses of thin-sections have been carried out on 51 rock samples from outcrops and on 5 rock samples from the drillcore in borehole KLX0 . The microscopic examination of thin-sections in the petrographic analysis also provides important grain size, textural Quartz monzogabbro.

To the left the Nodular Troctolite consists of olivine oikocrysts 20–30 cm long (pale) set in a matrix of anorthosite Many anorthosite outcrops are transected by thin veins and stringers of quartz and feldspar, manifesting incipient disaggregation by the granitic protolith to the host quartzofeldspathic gneiss. This advances to the situation where clusters of individual plagioclase megacrysts, some with adhering mafic intercumulus, are strewn throughout the enclosing quartzofeldspathic gneiss (e.g., Fig. 18.8A ). 2. ANORTHOSITE white course grained plagioclase MT. 3. APALITE fine pink CO. 4. BASALT olivine, La Bajada Hill NM Quarternary.