metamorphic rocks (8)

Question 1

Parent Rock

Answer 1

The rock from which a metamorphic rock formed

Question 2

Metamorphism

Answer 2

The changes in mineral composition and texture of a rock subjected to high temperature and pressures within Earth

Question 3

Metamorphic Grade

Answer 3

Degree to which a metamorphic rock changes from temperature and pressure

Question 4

Recrystallization

Answer 4

The formation of new mineral crystals in a rock that tend to be larger than the original crystals

Question 5

Geothermal Gradient

Answer 5

The gradual increase in temperature with depth in the crust. The average is 30degrees C/km in the upper crust

Question 6

Confining Pressure

Answer 6

Stress that is applied uniformly in all directions

Question 7

Differential Stress

Answer 7

Forces that are unequal in different directions

Question 8

Compressional Stress

Answer 8

Differential stress that shortens a rock body

Question 9

What are four agents that drive metamorphism?

Answer 9

Heat
Confining Pressure
Chemically Active Fluids
Differential Stress

Question 10

This agent of metamorphism is most important?

Answer 10

Heat

Question 11

What characteristic of a metamorphic rock is determined primarily by its parent rock?

Answer 11

Composition

Question 12

Texture

Answer 12

The size, shape, and distribution of the particles that collectively constitute a rock

Question 13

Foliation

Answer 13

A term for a linear arrangement of textural features often exhibited by metamorphic rocks

Question 14

Solid-State Flow

Answer 14

The solid-state flow of rock that occurs when rocks are exposed to extreme conditions of heat and pressure

Question 15

Rock Cleavage

Answer 15

The tendency of rocks to split along parallel closely spaced surfaces. These surfaces are often highly inclined to the bedding planes in the rock

Question 16

Salty Cleavage

Answer 16

A type of foliation that is characteristic of slates, in which there is parallel arrangement of fine-grained metamorphic minerals

Question 17

Gneissic Texture

Answer 17

A texture of metamorphic rocks in which dark and light silicate minerals are separated, giving the rock a banded appearance

Question 18

Nonfoliated

Answer 18

Describes metamorphic rocks that do not exhibit foliation

Question 19

Porphyroblastic Texture

Answer 19

A texture of metamorphic rocks in which particularly large grains (porphyroblasts) are surrounded by a fine-grained matrix of other minerals

Question 20

Slate

Answer 20

Foliated, fine grained, excellent rock cleavage (salty)

Question 21

Phyllite

Answer 21

Foliated, fine grained, glossy sheen

Question 22

Schist

Answer 22

Foliated, medium-to-coarse grained, micas dominate

Question 23

Gneiss

Answer 23

Foliated, coarse grained, banding of dark and light

Question 24

Marble

Answer 24

Nonfoliated, medium-to-coarse grained, soft

Question 25

Quartizite

Answer 25

Nonfoliated, medium-to-coarse grained, hard, quartz

Question 26

Hornfels

Answer 26

Nonfoliated, fine grained, tough, dark

Question 27

Contact Metamorphism

Answer 27

Changes in rock caused by the heat from a nearby magma body

Question 28

Aureole

Answer 28

A zone or halo of contact metamorphism found in the country rock surrounding an igneous intrusion

Question 29

Hydrothermal Metamorphism

Answer 29

Chemical alterations that occur as hot, ion-rich water circulates through fractures in rock

Question 30

Burial Metamorphism

Answer 30

Low-grade metamorphism that occurs in the lowest layers of very thick accumulations of sedimentary strata

Question 31

Regional Metamorphism

Answer 31

Metamorphism associated with large-scale mountain building

Question 32

Impact Metamorphism

Answer 32

Metamorphism that occurs when meteorites strike Earth's surface

Question 33

What are 3 rocks that are produced by contact metamorphism?

Answer 33

Hornfels Quartzite Marble

Question 34

What is the agent of hydrothermal metamorphism?

Answer 34

Hot water full of dissolved ions

Question 35

Which type of plate boundary is associated with regional metamorphism?

Answer 35

Convergent

Question 36

Index Mineral

Answer 36

A mineral that is a good indictor of the metamorphic environment in which it formed. Used to distinguish different zones of regional metamorphism

Question 37

Migmatite

Answer 37

A rock exhibiting both igneous and metamorphic rock characteristics. Such rocks may form when light-colored silicate minerals melt and then crystallize, while the dark silicate minerals remain solid

Question 38

Metamorphic Facies

Answer 38

A group of associated minerals that are used to establish the pressures and temperatures at which rocks undergo metamorphism