Metamorphism

Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture.

Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts, and hence quartzite is a metasandstone.

During the initial collision of the Asia and Indian plates, this granitic batholith was buried to depths of about 20 kilometres (12 mi) or more, highly metamorphosed, highly deformed, and partially remelted during the Eocene Period to form gneiss.

The kyanite quartzite and associated schist and gneiss consist of volcaniclastic sediments and volcanic rocks that have been altered by amphibolite grade metamorphism under pressure as high as 6.5 kb and temperatures as high as 600 °C.

Corundum occurs as a mineral in mica schist, gneiss, and some marbles in metamorphic terranes.

Talc dominantly forms from the metamorphism of magnesian minerals such as serpentine, pyroxene, amphibole, and olivine, in the presence of carbon dioxide and water.

The metamorphism of impure dolomite or other sedimentary rocks with high magnesium and low silica content also produces Mg-rich olivine, or forsterite.

It is found in metamorphic rocks as a product of contact metamorphism.

It is traditionally defined as metamorphism which involves a change in the chemical composition, excluding volatile components.

Ultra-high-pressure metamorphism refers to metamorphic processes at pressures high enough to stabilize coesite, the high-pressure polymorph of SiO2.

Aragonite is the high pressure polymorph of calcium carbonate. As such, it occurs in high pressure metamorphic rocks such as those formed at subduction zones.

It is the primary mineral in metamorphic marble.

Cordierite typically occurs in contact or regional metamorphism of pelitic rocks.

Forsterite also occurs in dolomitic marble which results from the metamorphism of high magnesium limestones and dolomites.

The mineral garnet is commonly found in metamorphic and to a lesser extent, igneous rocks.

Grossular is found in contact metamorphosed limestones with vesuvianite, diopside, wollastonite and wernerite.

Jadeite is formed only in the subduction zones of continental margins, where rock undergoes metamorphism at high pressure but relatively low temperature.

Kyanite occurs in biotite gneiss, mica schist, and hornfels, which are metamorphic rocks formed at high pressure during regional metamorphism of a protolith which is rich in aluminium (a pelitic protolith).

Lazurite is a product of contact metamorphism of limestone and is typically associated with calcite, pyrite, diopside, humite, forsterite, hauyne and muscovite.

Flake mica comes from several sources: the metamorphic rock called schist as a byproduct of processing feldspar and kaolin resources, from placer deposits, and pegmatites.

Tremolite occurs in metamorphosed dolomitic limestones, and actinolite in metamorphic greenschists/glaucophane schists.

It occurs most often in granite pegmatite and allied rock types and in certain low-grade metamorphic phyllites.

Spinel is found as a metamorphic mineral in metamorphosed limestones and silica-poor mudstones.

Serpentinization is a hydration and metamorphic transformation of ferromagnesian minerals, such as olivine and pyroxene, in mafic and ultramafic rock to produce serpentinite.

Marble is a metamorphic rock consisting of carbonate minerals (most commonly calcite (CaCO3) or dolomite (CaMg(CO3)2) that have recrystallized under the influence of heat and pressure

Gneiss ( NYSE) is a common and widely distributed type of metamorphic rock

Soapstone (also known as steatite or soaprock) is a talc-schist, which is a type of metamorphic rock

Serpentinite is a metamorphic rock composed predominantly of serpentine group minerals formed by serpentinization of mafic or ultramafic rocks

Most of the islands have a bedrock formed from ancient metamorphic rocks, and the climate is mild and oceanic.