metamorphism: Changes in Chemical Constituents

Chemical changes occurring during metamorphism also can rearrange the chemical constituents into assemblages stable in their new environment, thus often forming new minerals of essentially the same chemical composition as those occurring in the rock prior to metamorphism. For example, hornblende can be changed into garnet or pyroxene. The mineral composition of rocks may also be altered by the addition of new elements or by the removal of elements formerly present through the action of circulating liquids or gases or by recrystallization under pressure.

Sections in this article:

• Introduction
• Regional Metamorphism
• Local Metamorphism
• Changes in Chemical Constituents
• Foliation
• Characteristics of Metamorphism

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