metamorphic facies are a group of minerals that form at certain pressure and temperature conditions. For example if the minerals in the rock formed at pressures greater than 1 GPa and 500 degrees C, then this mineral assemblage will fall into the eclogite facies. mineral assemblages that undergo high presures but lower temperatures such as at convergent plate margins are known as the bluescist facies. At even lower temperatures is the greeenschist facies. Some of the minerals that fall into the eclogite facies are garnet and orthopyroxene. Some of the minerals in blueschist facies can be kyanite and gluacophane, and some minerals in the greenschist facies can be chlorite, epidote, and actinolite.
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