Metamorphism, metamorphic rocks

Metamorphism, Metamorphic Rocksand Hydrothermal Rocks... I DefinitionsII Controls on Metamorphic Characteristics A Composition of Parent Rock... metamorphism - the mineralogical, chemica

Metamorphism, Metamorphic Rocks

and Hydrothermal Rocks

I Definitions

II Controls on Metamorphic Characteristics

A) Composition of Parent Rock

metamorphism - the mineralogical, chemical, and structural adjustment of solid

rocks to physical and chemical conditions imposed at depth below the surface zones

of weathering and cementation, which differ from the conditions under which the rock originated

metamorphic rock - any rock derived from pre-existing rocks by mineralogical,

chemical, and/or structural changes, essentially in the solid state, in response to

marked changes in temperature, pressure, shearing stress, and chemical environment, generally at depth in the Earth's crust

metamorphic grade - the intensity of metamorphism, measured by the degree of

difference between the parent rock and the metamorphic rock

parent rock - the original rock from which a metamorphic rock was formed Parent

rocks may be igneous, sedimentary, or metamorphic

Foliated Metamorphic Rocks Non-foliated Metamorphic Rocks

Slate Phyllite Schist Gneiss

Anthracite Coal Hornfels

Marble Quartzite Serpentinite Soapstone

Composition of Parent Rock Temperature

Pressure Fluids Time Tectonic Setting

foliation - the planar structure that results from the flattening of the constituent

grains of a metamorphic rock

water and carbon dioxide most common metamorphic fluids

present along grain boundaries or in pore spaces of rocks

Fluids derived from several sources:

trapped in pore spaces when parent rock formed exuded from magmas

dehydration of water bearing minerals (e.g gypsum, clays)

metamorphic reactions themselves may liberate fluids:

often contain ions in solution, increasing the rate of chemical reactions

Contact Metamorphism Regional Metamorphism Hydrothermal Metamorphism Burial Metamorphism

Blueschist Metamorphism Eclogite Metamorphism