studies of the alkali feldspar granite

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  Pathways for 39Ar loss during step heating of alkali feldspar

  — Semantic Scholar extracted view of "Pathways for 39Ar loss during step heating of alkali feldspar megacrysts from the Shap granite UK Combined evidence from diffusion experiments and characterisation of heating induced texture modifications" by

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  Geochronology mineralogy and geochemistry of alkali feldspar granite

  — The alkali feldspar granite was derived from melting of Archean granodioritic rocks Coupled with other studies on sedimentary and volcanic successions in the Jiao Liao Ji Belt the unusual association of the A type alkali feldspar granite and albite granite indicates that the southern segment of the Jiao Liao Ji Belt experienced

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  Origin of alkali feldspar granites An example from the Poimena Granite

  — The Lottah Granite is a composite pluton of tin mineralised strongly peraluminous alkali feldspar granite which intrudes the Poimena Granite a major component of the mid Devonian Blue Tier Batholith of northeastern Tasmania Earlier workers interpreted the Lottah Granite as a metasomatised differentiate of the Poimena Granite

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  On the origin of alkali feldspar megacrysts in granitoids

  — data on alkali feldspar CSDs for rocks from the Cathedral Peak Granodiorite with the aim to gain new insights on alkali feldspar crystallization history and associated time scales so as to help us understand the origin of alkali feld spar megacrysts in granitoids Geological background The Late Cretaceous Tuolumne Intrusive Complex

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  Feldspar Group an overview ScienceDirect Topics

  Minerals of the feldspar group are the most abundant constituents of both the continental and oceanic crust of the Earth and the surface of the Moon making up more than 50% by volume Feldspars have been identified on Mars and are known from meteorites They are Na K and Ca aluminosilicates based on a 3 dimensional framework of linked Si and

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  Granite SpringerLink

  —a leucocratic granite with granitic texture and composed essentially of alkali feldspar and quartz Binary granite —a synonym of two mica granite O F and N L Bowen 1958 The origin of granite in the light of experimental studies in the system NaAlSi 3 O 8 KAlSi 3 O 8 SiO 2 H 2 O Mem Geol Soc Am 74 Google Scholar

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  Unraveling the pre metamorphic cooling history of the Koraput Alkaline

  — In alkali feldspar granite mesoperthites indicate higher temperature range than perthites The compositions of reintegrated mesoperthites of alkali gabbro syenite alkali feldspar granite are Ab 43 65 An 6 12 Or 29 49 Ab 52 67 An 1 4 Or 29 45 Ab 53 61 An 1 4 Or 36 46 respectively Table S7 Fig 8b

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  Postorogenic alkali feldspar granite and associated

  — The ± Ma 40 Ar 39 Ar muscovite Georgeville Pluton in mainland Nova Scotia is an epizonal body consisting of alkali feldspar granite and related pluton intrudes the ca 619 608 Ma arc related rocks of the Georgeville Group which comprises part of West Avalonia the largest terrane in the Canadian

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  Petrogenesis of Paleoproterozoic alkali feldspar granites associated

  — The Paleoproterozoic orogenic junctions between the Khondalite Belt and TNCO in Fengzhen and Huai an areas are intruded by dikes Fig 1 which consist of a variety of contemporaneous rock types including carbonatites pyroxenites syenites granites and gneisses Fig 2 a b These rocks are intimately associated and hybridise

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  Geology and mineralization of the Jabalat alkali feldspar granite

  — The Jabalat post tectonic granite pluton is composed of albite and oligoclase bearing low calcium F Sn and Rb rich subsolvus granites These granites display evidence of late magmatic granitophile and metallic element specialization resulting ultimately in the development of post magmatic metalliferous hydrothermal

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  Postorogenic alkali feldspar granite and associated

  — The ± Ma 40 Ar 39 Ar muscovite Georgeville Pluton in mainland Nova Scotia is an epizonal body consisting of alkali feldspar granite and related pluton intrudes the ca 619 608 Ma arc related rocks of the Georgeville Group which comprises part of West Avalonia the largest terrane in the Canadian

  Alkali feldspar syenite Geology is the Way

  — Numerous studies have determined that immiscibility occurs readily if a viscous silica rich melt contains certain levels of alkali or alkaline earth metals and fluorine F Dolejš and Baker 2007; Hess 1995 Hess 1996; Levin et al 1964; Thompson et al 2007 However most previous reports on immiscibility in alkaline granitic rocks were

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  Origin of alkali feldspar granites An example from the Poimena Granite

  Many other examples of alkali feldspar granite and much of the associated mineralisation are probably also of essentially primary magmatic origin rather than of metasomatic or hydrothermal origin as commonly interpreted 63 Previous studies of the Lot&h Granite COCKER 1977 Tio2 or Ti02 Of 1982

  On the origin of alkali feldspar megacrysts in granitoids

  — data on alkali feldspar CSDs for rocks from the Cathedral Peak Granodiorite with the aim to gain new insights on alkali feldspar crystallization history and associated time scales so as to help us understand the origin of alkali feld spar megacrysts in granitoids Geological background The Late Cretaceous Tuolumne Intrusive Complex

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  The nucleation and growth of alkali feldspars from hydrous

  Melting of plagioclase in granite and related systems composition of coexisting phases and kinetic observations The Second Hutton Symposium on the Origin of Granites and Related Rocks Reactive transport modelling of compacting siliciclastic sediment diagenesis

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  Late crystallization of K feldspar and the paradox of

  — K feldspar crystals >5 cm in greatest dimension are common in calc alkaline granites and granodiorites worldwide Such megacrysts are generally interpreted as having grown to large sizes early in a magma s crystallization history while they were largely molten owing to field relations such as megacryst alignment and megacryst rich clusters and to

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  Origin of alkali feldspar granites An example from the Poimena Granite

  — This paper aims to show that the Lottah Granite the alkali feldspar granite upon which earlier interpretations were largely based is genetically unrelated to the host biotite granite and that there and elsewhere in the world magmatic processes have been the primary controls on the chemical evolution mineralogy and mineralisation of

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  Late crystallization of K feldspar and the paradox of

  — K feldspar crystals >5 cm in greatest dimension are common in calc alkaline granites and granodiorites worldwide Such megacrysts are generally interpreted as having grown to large sizes early in

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  Generation of Cretaceous high silica granite by

  zogranite as well as alkali feldspar granite Previous studies of mineral assemblage and geochemistry show that the monzogranite is I type whereas the alkali feldspar granite is A type Qiu

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  Geochemistry of K‐feldspar and Muscovite in Rare‐element

  — K feldspar and muscovite crystallize through extensive periods of pegmatite and granite solidification K feldspar provides a suitable host for Rb NH 4 Cs Ca Sr Pb Ba Eu La and Li in the alkali position and B Ga Ge Fe Mg Ti and P in tetrahedral sites whereas in muscovite the most frequent substitutions are in the interlayer and

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  Postorogenic alkali feldspar granite and associated

  The ± Ma 40Ar 39Ar muscovite Georgeville Pluton in mainland Nova Scotia is an epizonal body consisting of alkali feldspar granite and related pegmatite

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  Skeletal quartz and dendritic biotite Witnesses of primary

  — Whole rock geochemical data show that the studied alkali feldspar granite derives from parent magma generated by partial melting of an old recycled continental crust in agreement with the regional geodynamic reconstruction Skrzypek et al 2014

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  The hydrothermal alkaline alteration of potassium feldspar A

  — These rocks were specifically chosen for their high alkali feldspar content which in turn makes them interesting candidates for hydrothermal K extraction studies This is the principal reason more common alkali feldspar bearing rock types like granite were not chosen for this study The samples were dry crushed and ground in an agate mortar

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  Petrogenetic implications of mineral chemistry and mode

  — The Sholayar alkaline syenite complex SASC 10°17′′′N 076°47′′′E figure 1b is emplaced within a terrain of high grade granite gneiss and mafic granulites having an orientation of WNW ESE and trending for about 8 km It shows a sharp contact with the country rocks which mainly comprise granitic gneiss and mafic

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  Feldspar minerals properties types uses ZME Science

  — The alkali feldspars are significant for their presence in granite and other felsic igneous rocks Common members include Orthoclase KAlSi3O8 Potassium rich typically displaying a salmon pink

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  PDF Nb/Ta Zr/Hf and REE fractionation in exotic

  — The White Tundra pegmatites are associated with the Keivy alkali feldspar granite complex in the Kola Peninsula NW Russia The host granites are aegirine arfvedsonite biotite arfvedsonite and

  Alkali Feldspar Granite ALEX STREKEISEN

  — The KCG and ACG are calc alkaline granitoids of mixed origin The distinction between the KCG K rich and K feldspar porphyritic Calc alkaline Granitoids and the ACG Amphibole rich Calc alkaline Granitoids is also underlined by the chemical data Fig 1 C The KCG have a low CaO content and a constantly high K 2 O content about