EASC 101- Lecture 4

Metamorphism occurs when a rock is subjected to from those in which it was formed

• a. air and temperature

• b. pressure and air

• c. temperature and pressure

• d. air and water

Factors that control the metamorphism include

• a. heat

• b. pressure

• c. fluids present

• d. all of the above

Confining pressure or uniform stress squeezes the rock

• a. From the sides and not from the top and bottom such that the rock thins

• b. diagonally such that the rock is flattened at 45 degrees

• c. equally from all directions reducing volume but producing no change in shape

• d. from the bottom and top such that the rock thins

Directed pressure of differential stress refers to the that are different

• a. unequal application of the pressure such that the body is distorted

• b. equally from all directions reducing volume but producing no change in shape

• c. a and b above

• d. none of the above

The metamorphic grade of the rock refers to

• a. the color of the rock

• b. the hardness of the rock

• c. the intensity of the metamorphism experienced by the rock

• d. the purity of the rock

In metamorphism, index minerals are minerals that

• a. share are particular color

• b. share particular cleavage

• c. form under specific pressure and temperature conditions such that they can be used to determine condition under which a rock formed.

• d. share particular streak.

Low grade metamorphism starts to take place at temperatures of around

• a. 200°C

• b. 600°C

• c. 1000˚C

• d. 1200°C

Burial metamorphism requires confining pressure and rise in temperatures and this occurs in

• a. deep sedimentary basins

• b. ocean trenches

• c. passive margins with high heat flow

• d. all of the above

Contact metamorphism occurs

• a. in deep lakes

• b. when rocks surrounding an igneous body are heated and altered

• c. at the bases of glaciers

• d. all of the above

Regional metamorphism takes place

• a. in continental interiors due to weight of sediments

• b. associated with earthquakes due to the pressure

• c. over wide areas from heat and pressure associated with convergent plate boundaries.

• d. all of the above