Phase equilibria of HP–UHP mica-schists in Jiangling
There are also some scholars trying to obtain HP–UHP metamorphic records from the main mineral assemblages of gneisses. For example, using the garnet–muscovite thermometer and the muscovite Si-content barometer, Wei et al. [14] calculated PT conditions of the mica-schist around eclogite in Jiangling as 650–660 °C at 1.8–2.0 GPa, and proposed that …
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Schist: Metamorphic Rock & Geology | Vaia
The texture of schist is what geologists refer to as 'schistosity,' a result of the preferred alignment of elongated mineral grains.Unlike other metamorphic rocks such as gneiss, schist exhibits a more pronounced foliation pattern, making the individual mineral grains visible to the naked eye.In addition to mica, schist can contain other minerals such as quartz, feldspar, …
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Petrographic features of the garnet-kyanite gneiss and mica schist…
Several large feldspar grains enclose quartz crystals and mica flakes. Garnet grains appear as large porphyroblasts with quartz, rutile and ilmenite inclusions wrapped by the main foliation (S2).
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Schist: Identification, Characteristics, and More
It can often be very difficult for people to identify schist, even with pictures and descriptions to compare to. This is because schist isn't primarily defined by its mineralogy, but rather by its texture. So what does schist look like? Schist has large, flattened grains of platy minerals like muscovite, biotite, and chlorite. Th…
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Schist
The specific mineral composition of a schist is indicated by placing the name or names of significant subordinate minerals in front of the word schist; commonly occurring types include biotite schist, muscovite-chlorite schist, garnet-mica schist, staurolite kyanite schist, and hornblende schist. ... Many porphyroblasts contain inclusions ...
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The mineralogy and chemical composition of garnets from …
THE MINERALOGY AND CHEMICAL COMPOSITION OF GARNETS FROM THE SCHIST-COMPLEX OF ... occurrence of almandite in the mica schists and in the accompan3"ing rocks of Nellore is well known. For instance, King x has recorded that the ... ment of some other mineral originally present in the garnet. Further, these inclusions axe not affected by the ...
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Biotite Mica Schist: Rockhounds Guide to Different Types
Garnet Schist is the same as Mica Schist, with the exception of the inclusions of Garnet. ... The primary differences between Schist and Gneiss are the mineral composition and texture. Schist has a more foliated or layered appearance, with the minerals aligned in parallel planes. While Gneiss typically has a banded appearance with alternating ...
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HISTORICAL METAMORPHISM OF MICA SCHIST IN …
± garnet + epidote ± calcite + zircon + opaque ± oxides. Mica schist has three types of primary fluid inclusions, namely liquid-rich two-phase fluid, vapor-rich two-phase fluid, and liquid mono-phase fluid, which are trapped in the quartz grains that compose the mica schist. In addition to the primary fluid, there is also
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The Mica Schist Family of Rocks
Composition Minerals and Texture: ... Other minerals which occur in mica-schist, in a manner similar to garnet, are staurolite, often with garnet, ... Inclusions of various kinds occur in mica-schists as in gneiss, thus veins and lenticular masses of quartz, deposited from solution in cracks and cavities opened by movement and foldings of the ...
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Mineralogical Characteristics of Garnet in Garnet Mica …
schist whose composition is consistent with Hongyi River ... The mineral assemblage of the garnet mica schist is quartz, muscovite, biotite, garnet, epidote and a small ... Inclusions of quartz ...
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Metamorphic P–T conditions and ages of garnet-biotite schists in …
The Dahongshan Group, situated at the southwestern margin of the Yangtze Block, represents a geological unit characterized by relatively high-grade metamorphism in the region. This paper investigates the garnet-biotite schist from the Laochanghe Formation of the Dahongshan Group, employing an integrated approach that includes petrological analysis, …
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Schist
Schist (/ ˈ ʃ ɪ s t / SHIST) is a medium-grained metamorphic rock showing pronounced schistosity (named for the rock). This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes or plates.This texture reflects a high content of platy minerals, such as mica, talc, chlorite, or …
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Grenvillian and early Paleozoic polyphase metamorphism …
The peak P-T conditions of the Neoproterozoic metamorphism were roughly constrained at 7.7-12.0 kbar and 634-680℃ for the garnet mica schist, based on stability field of mineral inclusions in Neoproterozoic zircons domains in P-T pseudosection, the relic garnet core composition and Ti-in-zircon thermometer.
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Rutile geochemistry and thermometry of eclogites and associated garnet
In this study, the geochemical parameters of rutile in HP rocks from the Biga Peninsula have been investigated. This study focuses on the trace element composition of rutiles and Zr-in-rutile thermometry of eclogites and associated garnet-mica schist from the Biga Peninsula in the northwest of Turkey (Fig. 1).The purpose of this study is to provide first …
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Kyanite-Garnet-Mica Schist | Geology 1501 | ECU
Type Metamorphic Rock Texture Foliated; Medium- to coarse-grained Composition Muscovite, Biotite, Quartz, Feldspar, Kyanite, and Garnet Index Minerals Kyanite and Garnet Color Medium silver gray to whitish …
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Growth zoning of garnet porphyroblasts: Grain boundary and
Given the link between garnet chemistry and matrix mineralogy and the zoning that is preserved around some inclusions, it is suggested that steps and associated chemical zones on the garnet surface may initially develop around partially enclosed inclusions during garnet growth (Figure 9). However, many inclusions lack associated zoning and as ...
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Properties, Formation, Occurrence, Uses
Almandine is a type of mineral that belongs to the garnet group, which is a diverse family of silicate minerals. ... with the degree of transparency depending on the quality of the crystal and any inclusions or impurities present. ... mica schist, amphibolite, and others. The specific type of parent rock and its mineral composition influence ...
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ANALYSES OF Two SEPARATED FRACTIONS GARNET …
Discontinuous compositional zoning in an almanditic garnet from a g.,rnct-mica-schist (64 K 176) from Sulitjelma, Northern Norway, as ... composed of fine-grained inclusions, and ... differences ...
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Detrital zircon and rutile U–Pb dating of garnet-mica schist in the
Based on almandine garnet and Fe-biotite mineral chemistry, garnet bearing mica-schist are affected by lower amphibolite facies metamorphism under 6.1 kbar pressure and approximately 547 °C. Moreover, detrital zircon U Pb dating was performed on 107 points to describe the maximum depositional age of this garnet-mica schist.
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Schist: Metamorphic Rock
Garnetiferous schist: This rock is composed of fine-grained muscovite mica with numerous visible grains of red garnet. The specimen shown is about two inches (five centimeters) across. …
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Polymetamorphic P–T evolution of the andalusite–garnet…
A sample of micaceous schist of the Cushamen Metamorphic Complex in the Cushamen area (northwestern North Patagonia, Argentina) preserves a complex mineral assemblage, including staurolite, andalusite, garnet, sillimanite, biotite, quartz, and plagioclase. This unit proves an opportunity to analyse a complex mineral association often related to …
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Metamorphic P–T paths and New Zircon U–Pb age data for garnet–mica
Garnet–mica schist samples were collected from the lower part of Wutai Group in the central Trans-North China Orogen for determination of the metamorphic P–T path and age and for better understanding the tectonic evolution of the NCC. ... a possible hot exhumation is suggested from the pressure peak (P max) defined by garnet rim composition ...
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Garnet micaschist
Garnets (with quartz inclusions) bordered by muscovite-biotite layers and quartz layers in a garnet micaschist. PPL image, 2x (Field of view = 7mm) XPL image, 2x (Field of view = 7mm)
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GARNET GRAIN SIZE ANALYSIS, GARNET …
of garnet across the central hinge of the syncline is a garnet mica schist. Additionally, garnet samples from drainages within the upper and lower schist units of the Wallace Formation were analyzed using electron micro probe analysis, wavelength dispersive x-ray fluorescence, and x-ray diffraction. Compositionally, the garnet consists
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Garnet micaschist
Schist is a medium-grained strongly-foliated crystalline metamorphic rock, formed by dynamic metamorphism, that can be readily split into thin flakes or slabs due to the well-developed parallelism of more than 50% of the minerals present, particularly those of lamellar or elongate prismatic habit, e.g., mica and amphiboles.
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8 Metamorphic Minerals and Metamorphic Rocks – Mineralogy
If schists contain prominent minerals, we name them accordingly. So the schist in Figure 8.23 is a garnet schist, and the one in Figure 8.28 is a muscovite schist, or simply a mica schist. Photos of staurolite schist and kyanite schist are included later in …
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The Mica Schist Family of Rocks
Composition Minerals and Texture: The essential minerals of mica-schist are quartz and mica, and it is especially the latter which gives the rock its particular character. Different varieties of mica occur; the most common is a silvery …
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Schist | Properties, Formation, Occurrence and Uses
Schist is a type of metamorphic rock characterized by its foliated texture, which means it possesses distinct layers or bands of minerals that have undergone significant physical and chemical changes due to heat, pressure, and other geological processes. The term "schist" is derived from the Greek word "schízein," meaning "to split," referencing the rock's tendency to …
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Mineral chemistry and geothermobarometry of metasedimentary …
Detrital zircon dating of a garnet-mica schist derived from a quartzofeldspathic source measured the youngest zircon age to be 450 ± 61 Ma (102 % concordant, Th/U = 0.02) Ma and the oldest zircon age to be 1529 ± 18 Ma (97 % concordant, Th/U = 0.02) Ma.
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Metamorphic P–T evolution of garnet-staurolite-biotite pelitic schist
The staurolite-garnet mica schist was further subjected to pseudosection analysis. ... a–c). The porphyroblast population is made up by poikiloblastic staurolite and garnet. Inclusions in garnet are quartz, biotite, muscovite and ilmenite, while staurolite has all the inclusions that are present in garnet plus some garnet and plagioclase ...
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