Anorthosite texture

Media in category "Anorthosite textures" The following 5 files are in this category, out of 5 total. Labradorescent plagioclase feldspar (Marcy Anorthosite, Mesoproterozoic, 1.16 Ga; Route 3 roadcut south of Bartlett Pond, New York State, USA) 3.jpg 4,000 × 3,000; 8.18 MB 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 silica mineral. The rock has had a complex metamorphic history. The texture reflects at least two episodes of shearing (followed by intense and partial recrystallization, respectively), one episode of cataclastic textures, developed in fine-grained to medium-grained gabbro and melagabbro layers; (4) size grading, most commonly developed in megacrystic anorthosite layers; (5) "spotted" texture in which pyroxene forms equant crystals that are more resistant to weathering than the plagioclase and, consequently, appear as "spots"; and (6) variable texture Feldspar (in anorthosite) Some varieties of gabbro have few dark minerals, and are made almost entirely of plagioclase feldspar. This rock shows the interlocking texture of the feldspars… The anorthosite highlands of the Moon are primary crust, formed as plagioclase crystallized out of the Moon's initial magma ocean and floated to the top; however, it is unlikely that Earth followed a similar pattern, as the Moon was a water-less system and Earth had water.

Anorthosite texture

More information about these rocks is included in chapters 11, 13, and 14 of Moorhouse. This is the first examination of intrusive rocks you will make. There are two 2010-01-01 · Free Online Library: Igneous structure and texture of the ~1.3 Ga Hosenbein anorthosite pluton (Nain, Labrador) and implications for the crystallization of massif-type anorthosite.(Report) by "Atlantic Geology"; Earth sciences Crystal structure Case studies Models Crystallization Research Crystals Structure Magma Natural history Plutonic rocks Observations Properties 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. The textures of plagioclase crystals within large olivine oikocrysts preserve the sequence of the formation of anorthosite.

The mesocumulate texture that characterizes leucogabbronorite-leuconorite is defined by higher proportions of intercumulus pyroxene and Fe-Ti oxide. TEXTURE • Anorthosite are leucocratic, coarse grained and hypidiomorphic.

6. Massive anorthosite has adcumulate texture comprising tightly packed cumulus plagioclase with accessory (<10 vol%) abundances of intercumulus pyroxene and Fe-Ti oxide. The mesocumulate texture that characterizes leucogabbronorite-leuconorite is defined by higher proportions of intercumulus pyroxene and Fe-Ti oxide. TEXTURE • Anorthosite are leucocratic, coarse grained and hypidiomorphic.

I14-05 – Andesite porphyry – you guessed it, porphyrictic texture. Identify the phenocrysts. 1709 (IU-40) – Identify the phenocryst and describe the texture. IU-31 (1826) – Identify the rock and texture However, the typical garnet symplectitic textures are totally absent in BAC, unlike those present in the Sittampundi anorthosite complex [30] [41] . Mafic granulites typically show granoblastic texture with sieved as well as coronal garnets, flakes of biotite, rounded grains of sphene.
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1709 (IU-40) – Identify the phenocryst and describe the texture. IU-31 (1826) – Identify the rock and texture However, the typical garnet symplectitic textures are totally absent in BAC, unlike those present in the Sittampundi anorthosite complex [30] [41] . Mafic granulites typically show granoblastic texture with sieved as well as coronal garnets, flakes of biotite, rounded grains of sphene.

Gabbro is available in dark grey to black colors whereas, Anorthosite is available in black, bluish - grey, brown, green, grey, light greenish grey, pink, white colors. The texture reflects at least two episodes of shearing (followed by intense and partial recrystallization, respectively), one episode of cataclastic deformation, and one or more episodes of shattering and fragmentation. TEXTURE • Anorthosite are leucocratic, coarse- grained and hypidiomorphic.
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Rapakivi is Finish for rotten or crumbly rock and describes the tendency of the rapakivi granite to easily weather, The Pipestone Lake anorthosite complex (PLAC) is an ca. 1 km thick x 17 megacrystic anorthosite layers; (5) "spotted" texture in which pyroxene forms equant (pyriclasites et anorthosites) associé à la série granulitique du port de Saleix pétrographique le plus fréquent ; leur texture est grano à granuloblastique et la The shear zone transects the Whitestone Anorthosite, located along the western margin of the Parry Sound Domain, and produces a range of new textures and Winter (2001) An Introduction toIgneous and. Metamorphic Petrology. Prentice Hall. Figure 20-1a. a.

The proportion of ferromagnesian minerals increases from anorthosite to ferrodiorite through leuconorites Anorthosite: The anorthosite is a fair1 y typical ferroan anorthosite in mode, texture, and mineral chemistry. Plagioclase makes up more than 95% of the rock. Orthopyroxene and augite are the most abundant accessory minerals, being present in roughly equal amounts in the available thin sections. Many of the anorthosite samples returned by astronauts from the Moon have a similar crumbly texture, not because of weathering by water but due to impact shock and shattering by meteorite bombardment. You'll notice a range of colors here. Anorthosite-mangerite-charnockite-granite (AMCG) magmatism is widespread throughout the Mesoproterozoic Grenville Province (), and nowhere else on Earth are massif anorthosite complexes, which underlie approximately ∼20% of the area, so abundant (Fig. 1; Corriveau et al., 2007; Morisset et al., 2008).

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. 6.