Chapter 07 Vocab

Question 1

Compression

Answer 1

A push or squeezing felt by a body.

Question 2

Contact Metamorphism

Answer 2

Metamorphism caused by heat conducted into country rock from an igneous intrusion.

Question 3

Dynamic Metamorphism

Answer 3

Metamorphism that occurs as a consequence of shearing alone, with no change in temperature or pressure.

Question 4

Dynamothermal Metamorphism

Answer 4

Metamorphism that involves heat, pressure, and shearing.

Question 5

Exhumation

Answer 5

The process (involving uplift and erosion) that returns deeply buried rocks to the surface.

Question 6

Foliation

Answer 6

Layering formed as a consequence of the alignment of mineral grains, or of compositional banding in a metamorphic rock.

Question 7

Gneiss

Answer 7

A compositionally banded metamorphic rock typically composed of alternating dark- and light-colored layers.

Question 8

Hornfels

Answer 8

Rock that undergoes metamorphism simply because of a change in temperature, without being subjected to differential stress.

Question 9

Marble

Answer 9

A metamorphic rock composed of calcite and transformed from a protolith of limestone.

Question 10

Metamorphic Aureole

Answer 10

The region around a pluton, stretching tens to hundreds of meters out, in which heat transferred into the country rock and metamorphosed the country rock.

Question 11

Metamorphic Facies

Answer 11

A set of metamorphic mineral assemblages indicative of metamorphism under a specific range of pressures and temperatures.

Question 12

Metamorphic Foliation

Answer 12

A fabric defined by parallel surfaces or layers that develop in a rock as a result of metamorphism; schistocity and gneissic layering are examples.

Question 13

Metamorphic Rock

Answer 13

Rock that forms when preexisting rock changes into new rock as a result of an increase in pressure and temperature and/or shearing under elevated temperatures; metamorphism occurs without the rock first becoming a melt or a sediment.

Question 14

Metamorphic Zone

Answer 14

The region between two metamorphic isograds, typically named after an index mineral found within the region.

Question 15

Metamorphism

Answer 15

The process by which one kind of rock transforms into a different kind of rock.

Question 16

Metasomatism

Answer 16

The process by which a rock’s overall chemical composition changes during metamorphism because of reactions with hot water that bring in or remove elements.

Question 17

Migmatite

Answer 17

A rock formed when gneiss is heated high enough so that it begins to partially melt, creating layers, or lenses, of new igneous rock that mix with layers of the relict gneiss.

Question 18

Mylonite

Answer 18

Rock formed during dynamic metamorphism and characterized by foliation that lies roughly parallel to the fault (shear zone) involved in the shearing process; mylonites have very fine grains formed by the nonbrittle subdivision of larger grains.

Question 19

Phyllite

Answer 19

A fine-grained metamorphic rock with a foliation caused by the preferred orientation of very fine-grained mica.

Question 20

Preferred Orientation

Answer 20

The metamorphic texture that exists where platy grains lie parallel to one another and/or elongate grains align in the same direction.

Question 21

Protolith

Answer 21

The original rock from which a metamorphic rock formed.

Question 22

Quartzite

Answer 22

A metamorphic rock composed of quartz and transformed from a protolith of quartz sandstone.

Question 23

Regional Metamorphism

Answer 23

Metamorphism of a broad region, usually the result of deep burial during an orogeny.

Question 24

Schist

Answer 24

A medium-to-coarse-grained metamorphic rock that possesses schistosity.

Question 25

Shield

Answer 25

An older, interior region of a continent.

Question 26

Shale

Answer 26

Fine-grained, low-grade metamorphic rock, formed by the metamorphism of shale.

Question 27

Thermal Metamorphism

Answer 27

Metamorphism caused by heat conducted into country rock from an igneous intrusion.