Lecture 8 Metamorphism, Metamorphic Rocks and Hydrothermal Rocks

Lecture Outline IDefinitions IIControls on Metamorphic Characteristics A)Composition of Parent Rock B)Temperature C)Pressure i.Differential Stress ii.Foliation D)Fluids E)Time IIITypes of Metamorphism A)Contact Metamorphism B)Regional Metamorphism IVPlate Tectonics and Metamorphism Physical Geology

Definitions 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. Physical Geology

Metamorphic Rocks Foliated Metamorphic RocksNon-foliated Metamorphic Rocks Slate Phyllite Schist Gneiss Anthracite Coal Hornfels Marble Quartzite Serpentinite Soapstone Physical Geology

Controls on Metamorphic Characteristics Composition of Parent Rock Temperature Pressure Fluids Time Tectonic Setting Physical Geology

Controls on Metamorphic Characteristics Parent Rock Physical Geology

Controls on Metamorphic Characteristics Temperature Physical Geology

Controls on Metamorphic Characteristics Pressure Physical Geology

Controls on Metamorphic Characteristics Pressure - Foliation foliation - the planar structure that results from the flattening of the constituent grains of a metamorphic rock Physical Geology

Controls on Metamorphic Characteristics T-P Diagram Physical Geology

Controls on Metamorphic Characteristics Temperature and Pressure Physical Geology

Controls on Metamorphic Characteristics Fluids 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 Physical Geology

Types of Metamorphism Contact Metamorphism Regional Metamorphism Hydrothermal Metamorphism Burial Metamorphism Blueschist Metamorphism Eclogite Metamorphism Physical Geology

Types of Metamorphism Contact Metamorphism Physical Geology

Types of Metamorphism Regional Metamorphism Physical Geology

Types of Metamorphism Progressive Metamorphism Physical Geology

Types of Metamorphism Hydrothermal Processes Physical Geology

Types of Metamorphism Hydrothermal Processes Physical Geology

Types of Metamorphism Hydrothermal Processes - Metasomatism Physical Geology

Types of Metamorphism Hydrothermal Processes - Veins Physical Geology

Metamorphism and Plate Tectonics Physical Geology

Metamorphism and Plate Tectonics Metamorphic Facies Physical Geology