We provide new petrological data of andalusite-kyanite-sillimanite-bearing pelitic schists from Nishidohira in the southern Abukuma Mountains, Northeast Japan. Investigation of the pressure-temperature (P-T) evolution of amphibolite-facies metamorphism in the region described the timing and tectonics of early Cretaceous …

Aluminosilicates (kyanite, sillimanite and andalusite) are useful pressure–temperature (P–T) indicators that can form in a range of rock types through different mineral reactions, including those that involve partial melting. However, the presence of xenocrystic or inherited grains may lead to spurious P–T interpretations. The …

Quartz‐rich veins in metapelitic schists of the Sanandaj‐Sirjan belt, Hamadan region, Iran, commonly contain two Al 2 SiO 5 polymorphs, and, more rarely, three coexisting Al 2 SiO 5 polymorphs. In most andalusite and sillimanite schists, the types of polymorphs in veins correlate with Al 2 SiO 5 polymorph(s) in the host rocks, …

Kyanite, andalusite, and sillimanite are found together in the cordierite-bearing mica schist of the Prichard formation of the Precambrian Belt series exposed in the Boehls Butte quadrangle in the southern part of the Idaho panhandle.

Textural relations and relative deformation features among the three polymorphs suggest the crystallization sequence andalusite → kyanite → sillimanite, with growth of …

Staurolite has partially pseudomorphed kyanite, and occurs intergrown with sillimanite. Garnet occurs in some metaquartzites and interlayered mica schists. Mica schists lack Al2SiO5 polymorphs.

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 Miscellaneous Blue-gray kyanite blades on some foliation surfaces; medium- to large-sized red-brown garnets Metamorphic Type …

Pressure-temperature evolution of andalusite-kyanite-sillimanite-bearing pelitic schists from Nishidohira, southern Abukuma Mountains, Northeast Japan: Implications for …

Powder and single-crystal diffraction data measured from the three geologically important Al 2 SiO 5 polymorphs, kyanite, andalusite and sillimanite, over the last six decades have given varying accounts of each polymorph's thermal expansion, the scatter between and even within experimental datasets often being quite large. …

In this study, we report kyanite, for the first time, from two different types of UHP schists in SW Tianshan. The kyanite is documented to be a peak UHP phase, either equilibrated with coesite in garnet or hosting coesite inclusions. ... When pseudomorphously replacing andalusite or sillimanite, kyanite may form as fibrous aggregates. In sample ...

Andalusite is an aluminum silicate (Al 2 SiO 5), sharing its chemical composition with kyanite and sillimanite.These three minerals are polymorphs, and are often summarized as the sillimanite minerals. Andalusite is stable at pressures below 4 kbar, and is formed especially by low-grade metamorphism, by low-grade contact, or …

It is commonly found in schists, gneisses, and granulites. One of the most notable features of sillimanite is its polymorphism. It exhibits three distinct polymorphs: sillimanite, andalusite, and kyanite. …

Luster is vitreous. Occurrence. Commonly forms in rock types that have undergone high pressures. Kyanite is usually found in metamorphic rocks such as pelitic schists and gneisses. Infrequently found in kimberlite, granitic pegmatite, and eclogite. Associated minerals include staurolite, garnet, sillimanite, and andalusite.

Andalusite and sillimanite mica schists were subjected to multiple episodes of recrystallization that resulted in the reaction sequence andalusite → sillimanite → andalusite. Kyanite crystallized in an adjacent area during the same time period. Kyanite from quartzite containing hematite is enriched in Fe 2 O 3 but andalusite. and ...

Sillimanite-bearing schists are strongly foliated, fine- to medium-grained, and characterized by their grayish-white color and resistance to weathering.These schists are encountered in Gabal Hafafit, and Wadi Allaqi, South Eastern Desert, Egypt. The major constituents are sillimanite (more than 25%), quartz, and plagioclase (El-Desoky, 2010; …

In the Lesjaverk, Norway, rock that contains andalusite, kyanite, and sillimanite, observation of the Al 2 SiO 5 polymorphs in thin section indicate crystallization Sequence (2). Temperatures were calculated using Zr-in-rutile thermometry; results of 580-650°C indicate that rutile likely equilibrated in the kyanite or sillimanite stability field.

Andalusite-kyanite-sillimanite-bearing pelitic schists from Nishidohira Peak P-T condition of 4.5–6.9 kbar and 630–660 °C kbar Max-P of ~9 kbar based on Raman …

The schists comprise kyanite-bearing sillimanite-muscovite schist and garnet-bearing sillimanite-muscovite-biotite schist. These rocks are dark gray with a strong foliation commonly defined by quartz ribbons and fine- to coarse-grained muscovite aggregates (1–10 mm). The schists are mainly composed of quartz ...

Kyanite schist outcrop near Powell in Iron County, Wisconsin. (Photo courtesy Tod Roush.) Kyanite is formed by the metamorphism of alumium-rich rocks, and is often associated with biotite, muscovite, almandine, staurolite, and sillimanite. It is indicative of relatively high pressures during metamorphism. ASHLAND COUNTY: Kyanite is reported in schists …

The new diagnostic assemblage is garnet + biotite + kyanite (sillimanite). The ... Enami M (1983) Petrology of pelitic schists in the oligoclase-biotite zone of the Sanbagawa metamorphic terrain, Japan: phase equilibria in the highest grade zone of a high-pressure intermediate type of metamorphic belt. J Metamorph Geol 1:141–161

• Kyanite zone. Schists with kyanite, biotite, muscovite, quartz, plagioclase, and usually garnet and staurolite • Sillimanite zone. Schists and gneisses with ... 0.37 GPa (~ 10 km), while kyanite →sillimanite at the sillimanite isograd only above this pressure The P-T phase diagram for the system Al 2 SiO 5

Sillimanite and massive kyanite in Georgia (a preliminary report) Creator: Furcron, Aurelius Sydney, 1899-Contributor to Resource: ... The variety of kyanite found disseminated in schists, and also the type of interlockingtabular blue-bladed crystals associated with quartz veins and pegmatites, have a unique, hardness. The hardness …

Large crystals (porphyroblasts) of Al-silicates such as garnet, kyanite, andalusite, and sillimanite often appear at some stage in the development of (aluminous) schistose rocks . In recent years, petrographic work on schists has often focused on petrofabric studies, the growth in time of porphyroblasts, and their relationship to schist matrix ...

Kyanite, andalusite, and sillimanite are found together in the cordierite-bearing mica schist of the Prichard formation of the Precambrian Belt series exposed in the Boehls Butte …

Abstract Regionally metamorphosed, muscovite-bearing quartzites from Sivrihisar, Turkey, contain coexisting andalusite, kyanite, and sillimanite. Kyanite is the most abundant polymorph and defines a lineation along with prismatic sillimanite, andalusite, staurolite, and elongate quartz. Andalusite is the most Fe-rich of the …

KYANITE, ANDALUSITE AND SILLIMANITE Kyanite, andalusite and sillimanite are naturally occurring polymorphic minerals that have the same chemical composition, Al 2 SiO 5 ... and schists. The occurrence and predominance of one of the polymorphic minerals over another reflects the stability field of each mineral, defined by the ...

Schists have mineral crystals large enough to be identified and usually have wavy, undulating foliation textures caused by micas and other platy minerals. Distinctively metamorphic minerals such as garnet, staurolite, kyanite, and sillimanite occur in schists, depending on the metamorphic grade and starting composition of the parent rock.

Sillimanite commonly occurs as fine-grained needle-like grains (fibrolite). Decrease in the modal content of kyanite, and the absence of K-feldspar association with kyanite indicate that sillimanite could have been derived by the polyphase transformation of kyanite (Mohan et al. 1989; Lal et al. 2005).

Lower-grade rocks preserve chloritoid+andalusite±kyanite in muscovite–chlorite phyllite, and higher-grade rocks contain andalusite+sillimanite (±kyanite)+staurolite±garnet in mica schists.

Kyanite (schists) quartz, biotite, muscovite, oligoclase, almandine, kyanite Sillimanite (schists & gneisses) quartz, biotite, muscovite, oligoclase, almandine, sillimanite Mineral assemblages for pelitic rocks of …