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The term pegmatite is thus purely a textural description. [6] [7] Geologists typically prefix the term with a compositional description, so that granitic pegmatite is a pegmatite with the composition of granite while nepheline syenite pegmatite is a pegmatite with the composition of nepheline syenite. [6]
The Tin Mountain pegmatite is roughly L-shaped, with the longer leg trending N7’W and the other trending N75’W. [2] It is approximately 200 m long and is 30 m wide at the maximum. [3] It is a vertically differentiated zoned pegmatite, and consists of five main zones: the wall zone, three intermediate zones, and a core. [2] [7]
Greisen is a highly altered granitic rock or pegmatite, usually composed predominantly of quartz and micas (mostly muscovite). Greisen is formed by self-generated alteration of a granite and is a class of moderate- to high-temperature magmatic-hydrothermal alteration related to the late-stage release of volatiles dissolved in a magma during the ...
Phaneritic rock: Anorthosite from the Stillwater Igneous Complex (Neoarchean; Montana) Igneous textures include the rock textures occurring in igneous rocks.Igneous textures are used by geologists in determining the mode of origin of igneous rocks and are used in rock classification.
Described by the United States Geological Survey as one of the greatest deposits of rare-earth minerals in the world, the pegmatite was the first place geologists discovered fergusonite, thorogummite, yttrialite, and nivenite. The pegmatite is centrally located in the Lone Grove pluton, a 1.6 Ga old rapakivi granite, intruded into Valley Spring ...
Pegmatite mines (9 P) Pages in category "Pegmatite" The following 3 pages are in this category, out of 3 total. This list may not reflect recent changes. M.
Quartzolite occurs as dykes, sills, veins, bosses and segregation masses; [3] [4] it is also found in association with greisen and pegmatite. [5] [6] [7] Quartzolite is an extremely rare type of rock. [8] No extrusive rock equivalent of quartzolite is known. [9]
The Maine Pegmatite Workshop curriculum includes: [9] Introduction to the nature of pegmatites; Introductory concepts of igneous rock formation and mineral composition; Overview of pegmatite mineralogy; Pegmatites in relation to other igneous rocks; The role of volatiles and fluxes in the crystallization of pegmatite melt