A Metamorphic Rock Formed From Granite

The end product of their metamorphism is a banded rock with a mineralogical composition like granite.

A metamorphic rock formed from granite.

Gneiss ˈnaɪs is a common and widely distributed type of metamorphic rock. The original rock is subjected to heat temperatures greater than 150 to 200 c and pressure 100 megapascals 1 000 bar or more causing profound physical or chemical change the protolith may be a sedimentary igneous or existing metamorphic rock. Slate is another common metamorphic rock that forms from shale. Gneissgranite gneiss is a metamorphic rock formed from granite gneiss schist quartzite.

It is usually composed primarily of the minerals quartz feldspar and mica. It is formed by dynamic metamorphism at high temperatures and high pressures that aligns the grains of mica hornblende and other flat or elongated minerals into thin layers or foliation. Gneiss is formed by high temperature and high pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. Granite gneiss can also form through the metamorphism of sedimentary rocks.

Schist comes from the ancient greek for split through latin and french. These rocks develop a platy or sheet like structure that reflects the direction that pressure was applied. The granitic rock in migmatite probably originated from partial melting of some of the metamorphic rock though in some migmatites the granite may have intruded the rock from deeper in the crust. Gneissgranite gneiss is a metamorphic rock formed from granite gneiss schist quartzite.

The preexisting rocks may be igneous sedimentary or other metamorphic rocks. A photograph of polished gneiss from the stock of a countertop vendor. When granite is subjected to intense heat and pressure it changes into a metamorphic rock called gneiss. Metamorphic rocks arise from the transformation of existing rock types in a process called metamorphism which means change in form.

Schist is a metamorphic rock that comes in almost infinite variety but its main characteristic is hinted at in its name. Granite is an igneous rock that forms when magma cools relatively slowly underground. Foliated means the parallel arrangement of certain mineral grains that gives the rock a striped appearance foliation forms when pressure squeezes the flat or elongate minerals within a rock so they become aligned. The view shown in the photo is about 12 inches across.

The only rock that granite forms is the metamorphic. What rock does granite form from heat and pressure. Orthogneiss is gneiss derived from igneous rock such as granite.