Metamorphic Rocks Flashcards
What is metamorphism?
The change of minerals or textures in the solid state.
What is the name of Alabama’s State
Rock?
marble
Name the major “agents” of
metamorphism. Briefly explain how each
agent causes metamorphism to occur –
give an example of each.
heat, pressure, and fluid
Describe similarities and differences
between directed and non-directed
pressure. Describe effects in minerals
and rocks caused by each type of
pressure.
directed pressure-changes shape due to equal pressures and becomes parallel.
non-directed pressure-changes size but does not change shape. unequal pressures from different directions.
What is foliation? How does foliation
develop? How would you recognize
foliation in a rock?
The alignment of the grains after they have been rotated from pressure. All grains would be aligned.
What is shock metamorphism?
Large amount of pressure and heat ie. from a meteorite that creates metamorphism
Where does intrusive contact metamorphism occur?
In “country rock” areas.
What does the “grade” of metamorphism
mean? What rock names are examples of
different grades? What are characteristics
of these rocks?
The degree to which rock has been changed.
Slate (low grades [low temp/low pressure]) - >
Schist (medium grade) - >
Gneiss (high grade) - >
Magma - >
Igneous
What are the names of the parent rocks
(protoliths) of the various kinds of
metamorphic rocks?
Limestone is a protolith of marble
Sandstone is the protolith of quartzite
Coal is sometimes classified as a
metamorphic rock. Explain the reasoning
behind this statement. Hint: review the
definition of metamorphism.
When it is heated and squeezed to high enough temperature and pressure it can be sonsidered a metamorphic rock.
Once a metamorphic rock is formed, it
must remain a metamorphic rock forever
more. True or False? Explain.
False, a metamorphic rock can have enough heat and pressure applied to become magma and then become an igneous rock.
What is hydrothermal metamorphism?
Where does it occur?
Occurs when midocean ridge is fractured by rising magma from the earths mantle. Fractures allow water to seep into the rock and when it is heated it becomes more chemically reactive and rises back up causing hydrothermal metamorphism.
What are the classifications of foliated rocks? Non-foliated rocks?
Foliated-parallel arangement of lighter and darker bands
Non foliated-random orientation of grains
Where do regional and contact metamorphism occur in plate tectonics?
Regional-in the mountain range
Contact-surrounding zones of magma
Know these sequences
Shale ->
Slate ->
Shale->Slate
Slate->Hornfels
Compare and contrast metamorphic grades.
