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plagioclase ( usually uncountable, plural plagioclases ) ( mineralogy) Any of a group of aluminum silicate feldspathic minerals ranging in their ratio of calcium to sodium . quotations . 2004, Richard Fortey, The Earth, Folio Society 2011, p. 51: These crystals are of one of the most abundant minerals in nature - feldspar; furthermore, they ...
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Plagioclase feldspars are important Na- and Ca-bearing aluminosilicates that occur in most igneous rocks, as well as in many metamorphic and sedimentary rocks. Plagioclases are fundamental constituents of the Earth's crust and also of the anorthosite crust of the Moon (the highlands). The name plagioclase derives from the Greek πλάγιος ...
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Granite with black biotite and feldspar, plagioclase, Rocks, mineral, igneous, Near Karamea, West CoaSt New Zealand . Plagioclase feldspar, Joins a quartz vein, Rocks, mineral, igneous, New Zealand . piece of raw sunstone. sunstone is a plagioclase feldspar, which when viewed from certain directions exhibits a spangled appearance. - plagioclase ...
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General Plagioclase Information : Chemical Formula: (Na,Ca)(Si,Al)4O8 : Composition: Molecular Weight = 270.77 gm Sodium 4.25 % Na 5.72 % Na 2 O: Calcium 7.40 % Ca 10.36 % CaO: Aluminum 9.96 % Al 18.83 % Al 2 O 3: Silicon 31.12 % Si 66.57 % SiO 2: Oxygen 47.27 % O: 100.00 % 101.48 % = TOTAL OXIDE
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Figure 1Fractured wall rock plagioclase.(a) Thin section scan of wall rock plagioclase (Plg), garnet (Grt), clinopyroxene (Cpx) and scapolite (Sc) adjacent to an eclogite facies pseudotachylyte (pst) on Holsnøy.(b) Fine-grained reaction products of clinozoisite (Czo) are associated with the microfractures; the box denotes the location of MF1.(c) Some microfractures in plagioclase display ...
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The plagioclases are all colorless, white, or gray, although the drabness is often broken by spectacular Schiller effects. Moonstones may be colored by impurities such as goethite (brown). Comments by Don Clark, CSM IMG Feldspars are our most common mineral, making up over 99% of the earth's crust.
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Abstract. Lingunite nanocrystals and amorphous plagioclase (maskelynite) are identified at the contacts between augite and labradorite wedge-shaped interfaces in the doleritic rocks of the Lockne impact structure in Sweden. The occurrence of lingunite suggests that the local pressure was above 19 GPa and the local temperature overwhelmed 1000 °C.
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These samples form part of a wider sample set characterized in terms of petrology, mineral chemistry and whole rock major and trace elements by Cooper et al. (2016) and Tollan et al. (2012), providing key context for plagioclase isotopic analyses. We also present whole rock Sr, Nd, and Pb isotope data for 15 of the characterized Martinique ...
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Plagioclase is part of WikiProject Rocks and minerals, an attempt at creating a standardized, informative, comprehensive and easy-to-use rocks and minerals resource.If you would like to participate, you can choose to edit this article, or visit the project page for more information. Rocks and minerals Wikipedia:WikiProject Rocks and minerals Template:WikiProject Rocks and minerals Rocks and ...
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Plagioclase feldspars Plagioclase feldspars At high temperatures, the solid solution series form the complete basis from pure albite (Ab), Na AlSi3O8, to pure anorthite (An), CaAl2Si2O8. Plagioclase feldspars, as rock-forming minerals, are more widely distributed and abundant than potassium feldspars and are found in igneous rocks, metamorphism ...
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Oligoclase Plagioclase Comments: Clear glassy crystalline oligoclase with milky quartz and muscovite. Location: Bakersville, Mitchell County, North Carolina, USA.
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also contain one or more of the following minerals: quartz, plagioclase, garnet, andalusite, staurolite, and/or kyanite. (2) Protoliths that are rich in iron, magnesium, and calcium. Possible protoliths include ... Which would be more useful to infer the given information about a metamorphic rock: its mineral composition or its chemical ...
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Advertising Information The plagioclase Mineral Series The Plagioclase series is a group of related feldspar minerals that essentially have the same formula but vary in their percentage of sodium and calcium. Albite and Anorthite are the end members of the series, with the intermediary minerals Oligoclase, Andesine, Labradorite, and Bytownite.
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This special breed of feldspar is an intermediate product between the compositions of Albite and Anorthosite, both plagioclase feldspars. Tilting the specimen back and forth causes an optical phenomenon known as labradorescence and is caused by several degrees of refraction from several planes within the mineral.
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Definition - Plagioclase is a series of tectosilicate (framework silicate) minerals within the feldspar group, that form a solid solution series ranging from pure albite (Ab), Na(AlSi 3 O 8), to pure anorthite (An), Ca(Al 2 Si 2 O 8).The two intermingle and form a continuous chemical range (called a solid-solution series) between albite and anorthite (the end-members of the series).
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The extrusive component of the Karoo Large Igneous Province, the Drakensberg Continental Flood basalts of South Africa and Lesotho, is mainly composed of altered tholeiitic basalts without uraniferous mineral phases that are suitable for high-precision dating (e.g. baddeleyite or zircon), and thus dating is restricted to 40 Ar/ 39 Ar groundmass and plagioclase.
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Orders of 0.46, 1.2, and 2.0 are obtained for oligoclase, andesine, and bytownite, respectively. This indicates that the reaction intermediate is more highly protonated in feldspars of higher aluminum content. The nonintegral reaction orders obtained demonstrate the importance of several surface species in the dissolution reaction.
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Plagioclase. Solid solution series between Na-rich end-member (albite) and Ca-rich end-member (anorthite). Triclinic shape contributes to interesting optical angles. (001) is a perfect cleavage, and (010) is also quite good. (110) is a very poor cleavage and is not usually seen in thin section. Cleavages intersect at about 93-94 o angles.
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phenocrysts of plagioclase, clinopyroxene, and orthopyrox-ene in a glassy matrix that contains microlites of the same minerals and magnetite (Rapien, 1998; Rapien et al., 2003). Phenocrysts comprise 50-70 volume percent of the 1988 samples, and the order of abundance of phenocrysts
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Aug 19, 2022Labradorite is a silicate mineral, part of the feldspar Plagioclase, mineral series(of anorthite-albite). labradorite forms from layers of magma cooling (crystallizing) one on top of another.
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Acid plagioclase mineral data, information about Acid plagioclase, its properties and worldwide locations. LIVE REPORT! Greenland! - last updated 5 minutes ago.
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Various trace element data on 4 thin sections of lunar sample 60025. This set includes only data taken from plagioclase minerals present in thin section. These data were gathered via laser ablation (LA) ICP-MS at the University of Notre Dame MITERAC facility. Dataset is used for trace element modeling of lunar material.
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The bulk content of plagioclase in leucocratic gabbro of the Kharaelakh intrusion is up to 80%. Two generations of plagioclase have been distinguished: (1) earlier (An 70) and (2) later (An 80); An 100 is occasional (Geologiya., 2020). The content of plagioclase in olivine-free and olivine-bearing gabbro-dolerite is 50-60%.
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The steady-state dissolution rates of plagioclase feldspars into inorganic acid solutions in a flow-through reactor increased with Al content of the mineral from 1.4 {circ} 10{sup {minus}11} mol Si/m{sup 2}/s for albite to 5.6 {circ} 10{sup -9} mol Si/m{sup 2}/s for bytownite.
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Although plagioclase is one of the major constituent minerals in both chondritic and achondritic meteorites, the application for the estimate of shock conditions had not been straightforward owing...
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For plagioclase, LOD are <2% of reported abundances for Ca, Fe, Ga, Sr, Ba, La, and Ce, 4%-5% for Ti and Zn, 8% for Pr, and ∼18% for Nd and Eu. The high LOD for Pr, Nd, and Eu is due to the small spot size. Results of Hbl and plagioclase analyses are presented in Supplemental Files 3 and 4 ( footnote 1 ), respectively.
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Plagioclase is a subdominant mineral in the Kobe meteorite. The structural state of plagioclase, i.e., the dis-tribution of Al and Si in the four symmetrically nonequiv-alent tetrahedral sites of the framework, is sensitive to the temperature at which the feldspar forms (Tuttle and Bowen, 1950; Smith and Yoder, 1956; Bambauer et al.,
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The concentration of La in plagioclase (Table 1) creates an even bigger problem. It decreases from 4.7 ppm at F 64 to 1.7 ppm at F 20. We emphasize this interval only, because above this level in the intrusion apatite becomes a cumulus mineral, and contains high concentrations of REE which affects simple Rayleigh Law fractionation.
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Mineral reactions in closed systems involving amphibole and plagioclase ANonrw JonN ZrNcc* Institute of Mineralogy and Petrology, Mining University koben, 4-8700 Leoben, Austria Ansrucr Reactions are derived involving solid solutions of amphibole and plagioclase as well as end-members of spinel, olivine, orthopyroxene, clinopyroxene, and quartz.
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It is postulated that the sericitization resulted from the action of externally derived secondary hydrothermal fluids, which gained access to the pores in the plagioclase via now sealed microfractures, formed either by contraction during cooling of the Rosses Complex, or more likely by hydraulic fracturing by the fluids themselves.
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Compared to other rocks, protolith of amphibolite (sample M16-42) could be enriched in low-REE mineral, for instance, in plagioclase. This is confirmed by the high Al 2 O 3 content in the rock and positive Rb and Sr anomalies, whereas the absence of the positive Eu anomaly could be related to the intrusive rather than effusive nature of ...
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OCCURRENCE & Use. Occurrence. Plagioclase Feldspar is the most common mineral found on Earth due to its high stability and resistance to erosion. Because of this resistance, plagioclase feldspar is frequently found in many sedimentary rocks throughout Earth (Neese 2012). However, the mineral's original formation is deeper within the Earth ...
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OCCURRENCE & Use Occurrence Plagioclase Feldspar is the most common mineral found on Earth due to its high stability and resistance to erosion. Because of this resistance, plagioclase feldspar is frequently found in many sedimentary rocks throughout Earth (Neese 2012).
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On Earth, SiO 2 (silica) concentrations are used as a 1st-order chemical classification parameter. On the Moon, the three major minerals, plagioclase feldspar, pyroxene, and olivine, all have about the same SiO 2 concentration, so SiO 2 does not vary much among lunar rocks and isn't particularly useful for classification. "KREEPic" rocks often contain minor amounts of silica minerals ...
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Plagioclase, or a plagioclase feldspar, is a solid solution formed by the reaction of albite and anorthite. Only a small solid solution exists between K-feldspar and anorthite, and immiscibility occurs in the two other solid solutions at temperatures found in the Earth's crust. Albite is classified as a plagioclase or alkali mineral.
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Advertising Information The Mineral oligoclase Oligoclase belongs to the Plagioclase Feldspar group, an isomorphous solid solution series. Albite is one member, containing sodium and no calcium. The other end member, Anorthite, contains calcium and no sodium. Oligoclase is an intermediary member of this series.
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(a) They are plagioclase-bearing tectonites in which plagioclase is the dominant constituent by volume (> 50%). (b) They were deformed under amphibolite or granulite facies conditions, corresponding to the mechanically ductile domain for plagioclase (Tul- lis, 1983). (c) The plagioclase grains display abundant
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Plagioclase mineral Monthly Tech-Tip from Tony Hansen SignUp No tracking! No ads! That's why this page loads quickly! All Minerals Plagioclase A abundant sodium calcium feldspar mineral. Na 2 O 9.5%, CaO 4.0%, Al 2 O 3 22.5%, SiO 2 68.7% Related Information Links By Tony Hansen Tell Us How to Improve This Page
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Plagioclase Labradorite. Comments: Dual view of a cleavage fragment of labradorite showing the multi-colored labradorescence (schiller effect) and the same area viewed without the color.The color is due to optical interference on Bøggild exsolution lamellae. Location: Ihosy, Betroka district, Toliara Province, Madagascar.Scale: Picture size 3x3 cm. ...
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Plagioclase minerals are important constituents of many metamorphic rocks, such as gneiss, where they can be inherited from an igneous protolith or formed during the regional metamorphism of sedimentary rocks. Plagioclase is a common clast produced during the weathering of igneous and metamorphic rocks.
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