Metamorphic Rocks Quiz

Which of the following best defines metamorphic rocks and distinguishes them from igneous rocks?

• Metamorphic rocks are formed from the cooling and solidification of magma or lava and are primarily composed of silicate minerals.

• Metamorphic rocks are formed through the alteration of pre-existing rocks in the presence of high heat, pressure, or chemically active fluids, unlike igneous rocks, which are formed from the solidification of magma or lava.

• Metamorphic rocks are organic compounds that have been pressurized and heated below the Earth's surface, similar to how igneous rocks are formed.

• Metamorphic rocks are sedimentary rocks that have been compacted and cemented together over time, which is a process not related to the formation of igneous rocks.

What is the rock before metamorphism called? What types of rocks can become metamorphosed?

• Sedimentary rocks and igneous rocks

• Metamorphic rocks only

• Sedimentary rocks only

• Igneous rocks only

Regarding heat, what happens to temperature as you go deeper into the earth?

• It decreases

• It increases

• It remains constant

• It fluctuates unpredictably

What happens to pressure with increasing depth into the earth?

• It decreases

• It increases

• It remains constant

• It first increases, then decreases

At what types of tectonic boundaries do we see high pressures at the earth’s surface?

• Convergent boundaries

• Divergent boundaries

• Transform boundaries

• All of the above

During metamorphism, water (fluids) can be found in the parent rock, interacts with minerals by ______, and enters the rocks through ______.

• changing their chemical composition, cracks and pores

• evaporating all minerals, direct absorption

• freezing into ice, sublimation

• none of the above

The parent rock (protolith) contains minerals (with elements). So after metamorphism, the new minerals are made of the same ‘stuff’ that the protolith had (or less). NEW elements aren’t created, but new MINERALS can be created by the rearrangement of what was already there (or less, if fluids removed ions). How much time does it take to make a metamorphic rock?

• Less than a million years

• 1 to 10 million years

• 10 to 100 million years

• More than 100 million years

What are the two types of pressures?

• Atmospheric and Absolute

• Static and Dynamic

• Positive and Negative

• Gauge and Absolute

What is foliated texture, and how can you tell the direction of pressure based on the foliation direction?

• Foliated texture is a repetitive layering in metamorphic rocks, and the direction of pressure can be inferred perpendicular to the foliation.

• Foliated texture is a type of igneous rock texture characterized by large crystals, and the direction of pressure is unrelated to foliation.

• Foliated texture refers to the smoothness of sedimentary rocks, and pressure direction can be determined parallel to the foliation.

• Foliated texture is a pattern seen in volcanic rocks, and the direction of pressure cannot be determined.

Rank the following foliated textures by the amount of pressure required for their formation, from least to greatest

• slate, phyllite, schist, gneiss, migmatite

• migmatite, gneiss, schist, phyllite, slate

• slate, migmatite, gneiss, schist, phyllite

• phyllite, schist, gneiss, migmatite, slate