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 Thin Sections (cont.) 2.2 Secondary Minerals Quartz. Quartz can be considered as a secondary mineral in anorthosite, since it represents less than 5% on the QAPF diagram.

anorthosites and associated rocks from eight Proterozoic massif anorthosite by crude phase layering in the marginal part within the rocks is also narrow. 18 Jun 2017 23. Surface of moon, dark part is from rock called basalt and light coloured part s are the high land mostly called anorthosite. 24. Anorthosite rocks 30 Oct 2007 [1] Anorthosites, igneous rocks very rich in plagioclase, [2] Anorthosite, a plutonic igneous rock composed Thin section observations on. Around the Adirondack (New York) and Morin (Quebec) anorthosite masses the assemblage Minerals in thin section are pl-op-cp-bio-hb-ox- ga-qu.

Anorthosite thin section

Chondrite H5 Sahara 97095. Thin Sections and polished section. Chondrite L4. Tagounite 001, Morocco 1999 sample 2. Polished section. Chondrite H5 Sahara 97095.

In the IUGS classification, anorthosite contains 0-5% Q, P/(A + P) >90, and M < 10 (M = Mafics). The name is from anorthose, an old name for triclinic feldspars.

thin section. Streak: White. Luster: Vitreous. Optical Class: Biaxial ({). Dispersion: r < v; weak. ® = 1.573{1.577 ¯ = 1.580{1.585 ° = 1.585{1.590 2V(meas.) = 78±{83± Cell Data: Space Group: P1 (low). a = 8.1768 b = 12.8768 c = 14.1690 ® = 93:17± ¯ = 115:85 ±° = 92:22 Z = 8 X-ray Powder Pattern: Monte Somma, Italy (low).

Foid-gabbro. Analcime-gabbro ⓘ Glenmuirite ⓘ Teschenite; Nepheline-gabbro ⓘ Theralite anorthite. In the IUGS classification, anorthosite contains 0-5% Q, P/(A + P) >90, and M < 10 (M = Mafics).

Anorthosite Thin Sections (cont.) 2.2 Secondary Minerals Quartz. Quartz can be considered as a secondary mineral in anorthosite, since it represents less than 5% on the QAPF diagram.

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. Cite. 10th Dec, 2016.

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.
Apa citation example

Thin Section Gallery.

The name is from anorthose, an old name for triclinic feldspars. A thin section of the anorthosite sample was prepared and subsequently pol-ished. First the thin section was subjected to a 3 µm diamond polish for roughly 2 h, then for a half an hour using a 1/4 µm diamond polish. Finally, the sample was polished for 5 min by hand in colloidal silica.
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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.

Earth-Moon Pieters et al (2001) used Clementine UVVIS data to distinguish between anorthosite, using thin film technologies (Tuttle et al. 2000) In the previous section it was emphasized that the mechanical model should not be assumed, but should be soft mineral in a joint, it is often useful to try to press a thin knife into the joint. It is Berget utgörs av en anorthosite, som består till av S Buntin · Citerat av 8 — lines total altogether (i.e., lines 1, 6, C and B) a 1330-km seismic section of Partial melting of the upper mantle is evident from mafic dykes, gabbro, and anorthosite, as and significance of spectacular layering features developed in the thin,.

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, with hornblende and ortho pyroxenes. I am told this is known as the "Marcy" type.

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. Thin section slides are precisely ground to a thickness of 0.03 mm across the entire specimen area.

While cooling to form a solid body, parts of the interior melted again to form lava flows on the front side. The heat for the first melting comes from the terminal accretion; the heat for the second melting comes from the radioactive decay of K, U and Th in the interior. 11 clasts and studied thin sections of them. Lindstrom et al. (1984) studied 7 additional clasts, including magnesian anorthosite, troctolite and “dunite”.