Metamorphic Roks

METAMORPHIC ROCKS
Metamorphic rocks are altered forms of pre-existing rocks which might have been igneous or sedimentary. The alternation may be due to either heat or pressure or by both acting together. Un er t e effect of pressure and temperature certain of the original miners are no longer stable and give place to new minerals. Quartz, e spar, and hornblende are stable under both igneous and metamorphic conditions. In addition to new minerals, new textures arise during the process of alteration or metamorphism. Rocks not altered beyond recognition include quartzite (from sandstone) and slate (from clay). Rocks altered beyond recognition include rocks known as gneisses and schists.

The original rock-forming material and the names of original rocks and metamorphic rocks produced by it are given below.
MineralOriginal rock Metamorphic rock
SandSandstone Quartzite
Clay Shale Slate, mica-schist
Calcium
Carbonates Limestone Marble

mudstone argillite

Granite Gneiss

 SlateSchist

Basalt Amphibolite

igneous to metamorphic
igneous to metamorphic


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