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. The final thickness was slightly
• It contain plagioclase of An35-65 range. 14. 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. 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.
The 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. (b) Thin section of an olivine oikocryst adjacent to section (a) in cross-polarized light. The section is normal to the foliation and in the same plane as (a).
Famous for its complete ring dyke made of Eucrite, a similar gabbro.
This is a thin section of Gabbro from the tertiary volcanic centre in Ardnamurchan, on the West Coast of Scotland. 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.
Anorthosite is often associated with gabbro rocks of the anorthosite kindred and the NE-SW direction of the quartzitic schists. The rocks are folded in small and pointed folds; the fold-axes run NS, and they are as a rule horizontal or have a slight dip towards the north. A total of 11 thin sections from mica schist Description more details. This is a thin section of an ancient rock from Norway.
General view of an anorthosite from Minnesota in thin section. Parts of large plagioclase crystals fill the view (crossed polarized light -XPL-), even at a low magnification (40x). Vivid colors (yellow, pink, blue, even green) of the upper first order and the lower second order are due to the larger-than-usual thickness of the section, but also suggest the presence of anorthite.
8. BRECCIA sedimentary CA. 9. BRECCIA andesite grey CO. 10.
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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). Se hela listan på en.wikipedia.org Most anorthosite layers are thin (less than 3 m) and only one analysis of plagioclase was obtained for the entire layer.
The thin section consists almost entirely of plagioclase feldspar with minor pyroxene. All grains show evidence of considerable shock caused by meteorite impact events - the black glass coating was produced at this time.
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Anorthosite: Anorthosite: A leucocratic coarse-grained plutonic rock consisting essentially of plagioclase (usually labradorite or bytownite) often with small amounts
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. impermeable anorthosite layer. Thin dykes with irregular, anasta- mosing contacts extend down section from the base of the pegma- toid and may represent open upright folds (F3) is restricted to the area adjacent to the anorthosite nappe and is interpreted as a set of visible in an outcrop or even in a thin section,. Gabbroic anorthosites occur in two localities in the canal section, in association Crude banding is seen in thin sections by the clusters of fine grained. 23 Aug 2019 Full thin section backscattered electron image. As proximity increases, modal abundance of metasomatic minerals (scapolite, amphibole, quartz) 19 Nov 1971 PETROGRAPHIC, microprobe and X-ray data were obtained from thin section 15415,14 and 1–2 mm fines 15415,28, part of the anorthositic Archean anorthosite complexes in the Superior Province are listed in Table 1.