Metamorphic Rocks Flashcards
What are the three agents of metamorphism?
Heat, Pressure, chemically active fluids.
What causes heat metamorphism?
geothermic gradient, magma, and friction
What causes pressure metamorphism?
Depth, directed pressure,
How do chemically active fluid metamorphose rock?
depth, hydrothermal fluids
what 3 changes result from metamorphism
increased density, coarsening of crystals, foliation
what is foliation?
alignment of platy or engate mineral grains
what is rock cleavage?
how a rock breaks
what is a protolith?
the stone before it was metamorphose.
what are the two categories prior to naming?
foliated and nonfoliated
shale, fine grained, dull luster
slate
shale, fine grained, sheen, crenulations
phyllite
shale, coarse grained, mica minerals
schist
shale, coarse, felsic and mafic bands
gneiss
granite, coarse, felsic and mafic bands
gneiss
basalt, coarse, aligned black prisms
amphibolite
conglomerate, flattened pebbles
metacongomerate
limestone, coarse grained, calcite crystals
marble
sandstone, coarse grained, quartz crystals
quartzite
coal, “black gold”, gold sheen, very clean
anthracite
steps in the formation of coal
- accumulation of organic remains in tropical swamp environment
- organic material forms peat
- organic material forms lignite
- organics further concentrated to form bituminous coal
- heat and pressure form antracite
ultramafic, green, glossy sheen
serpentinite
ultramafic, soapy feel, talc dominates
soapstone
any, spotted, from contact metamorphism
hornfels
what are index minerals
metamorphic minerals that indicate the temperature associated with metamorphic alteration
