Chapter 8 - Metamorphic Rocks Flashcards
Metamorphic Rocks (20 cards)
Duration and rate of deformation are not important factors in metamorphism.
TRUE
Metamorphism usually starts around 300oC.
FALSE
A zone of contact metamorphism found in the rock surrounding an igneous intrusion is called a?
AUREOLE
A very fine grained, low grade metamorphic rock that results from metamorphism of shale is?
SLATE
The process by which large amounts of hot fluids flow into a rock and alter its chemical composition is what type of metamorphism?
HYDROTHERMAL
Which of the following correctly lists foliated metamorphic rocks from low to high grade?
PHYLLITE > SCHIST > GNEISS
Metamorphic processes can be seen because metamorphic rocks form at the Earth’s surface.
FALSE
What does it mean to say that a metamorphic rock is high grade?
IT WAS FORMED IN HIGH TEMPERATURE CONDITIONS
Which of the following rocks cannot be metamorphosed?
SHALE, SCHIST, GRANITE = ALL CAN BE METAMORPHOSED
Metamorphism can involve any of the following except:
MELTING OF ROCK TO FORM MAGMA
An asteroid crashes to Earth and lands in the ocean, colliding with a mid-ocean ridge. What types of metamorphic rocks would you expect to find at the impact site?
HYDROTHERMAL METAMORPHISM AND SHOCK METAMORPHISM
If a rock is subjected to differential stress, then it means that
THE AMOUNT OF STRESS IS GREATER IN SOME DIRECTIONS THAT IN OTHERS
Why can rocks that contain platy minerals produce foliated textures when they metamorphose?
PLATY MINERALS ARE MORE SENSITIVE TO DIRECTED PRESSURE THAN NONPLATY MINERALS AND THEREFORE ALIGN AT SPECIFIC ANGLES TO APPLIED PRESSURE
Nonfoliated metamorphic rocks most commonly form when parent rocks:
CONTAIN NO PLATY MINERALS OR ARE NOT EXPOSED TO DIRECTED PRESSURE
A metamorphic petrologist is studying a sample of gneiss, which has distinct light and dark bands of platy minerals. The most appropriate conclusion for the petrologist to draw is that this rock formed by:
REGIONAL METAMORPHISM
What rock characteristic do geologists use to identify metamorphic facies?
MINERAL ASSEMBLAGES
Why is the zeolite facies characterized by low-density, fine-grained minerals?
ZEOLITES FORM AT LOW TEMPERATURES AND LOW PRESSURES
After examining rock samples from a particular outcrop, a geologist concludes that the rocks formed at an ancient subduction zone. The presence of which metamorphic facies best supports this conclusion?
BLUESCHIST
What types of metamorphism are you most likely to find at subduction zones?
REGIONAL & CONTACT METAMORPHISM
Why are metamorphic rocks often found associated with intrusive igneous rocks?
HEAT & FLUIDS FROM MAGMA CAN ACT AS METAMORPHIC AGENTS ON THE SURROUNDING ROCK
