6 - Metamorphism and Metamorphic Rocks

Question 1

rocks (igneous, sedimentary or metamorphic) that changed from its original form by extreme heat, pressure and fluid activity into an all-new form of rock

Answer 1

Metamorphic rocks

Question 2

meta means…

Answer 2

change

Question 3

morph means…

Answer 3

form

Question 4

causes the minerals in the rock to become unstable so they either reorient themselves into layers, or recrystallize into larger crystals.

Answer 4

Metamorphism

Question 5

Parent (SHALE)

Answer 5

Daughter (SLATE)

Question 6

Parent (GRANITE)

Answer 6

Daughter (GNEISS)

Question 7

Parent (QUARTZ)

Answer 7

Daughter (QUARTZITE)

Question 8

Parent (Bituminous Coal)

Answer 8

Daughter (Anthracite)

Question 9

Temperature increase with the depth of burial

Core of the earth is relatively warmer than the outer crust

Answer 9

Geothermal Gradient

Question 10

uniform rock pressure, produces equal intensity of pressure from all directions.

Answer 10

Uniform (Lithostatic Pressure)

Question 11

produces minerals grow in the line of resistance (perpendicular to the direction of maximum pressure) to cause banding within the rocks.

Answer 11

Directed Pressure

Question 12

the process on which a rock’s chemistry changes as well as its assemblage

Answer 12

Metasomatism

Question 13

the change in the shape of the rocks due to the force of stress, usually movement of a fault zone.

Answer 13

Strain

Question 14

is the presence of mineral layers, which is an important feature for classifying mineral rocks.

Answer 14

Foliation

Question 15

the most common process for the occurrence of metamorphic rocks. These rocks were typically exposed to tectonic forces and associated high temperatures and pressures ONLY.

Answer 15

REGIONAL METAMORPHISM or DYNAMOTHERMAL METAMORPHISM

Question 16

the process by which the country rock that surrounds a hot magma intrusion is metamorphosed by the high heat flow coming from the intrusion.

Answer 16

CONTACT METAMORPHISM or THERMAL METAMORPHISM

Question 17

the zone of metamorphism that surrounds the intrusion.

Answer 17

Halo or Aureole

Question 18

the processes which affect rocks, usually involving water at lower temperatures and pressures than metamorphism

Answer 18

Rock Alteration

Question 19

commonly localized within a few meters of major faults or fractures, it may occur throughout zones a kilometer or more across.

Answer 19

Alteration

Question 20

is the breaking down of rocks which involves water and ice in the process.

Answer 20

Weathering

Question 21

caused by the effects of changing temperature on rocks, causing the rock to break apart. The process is sometimes assisted by water.

Answer 21

Physical weathering

Question 22

occurs when water continually seeps into cracks, freezes and expands, eventually breaking the rock apart.

Answer 22

Freeze-thaw

Question 23

occurs as cracks develop parallel to the land surface a consequence of the reduction in pressure during uplift and erosion.

Answer 23

Exfoliation

Question 24

caused by rain water reacting with the mineral grains in rocks to form new minerals (clays) and soluble salts.

Answer 24

Chemical weathering

Question 25

• removal of rock in solution by acidic rainwater. In particular, limestone is weathered by rainwater containing dissolved CO2, (this process is sometimes called carbonation).

Answer 25

Solution

Question 26

• the breakdown of rock by acidic water to produce clay and soluble salts.

Answer 26

Hydrolysis

Question 27

• the breakdown of rock by oxygen and water, often giving iron-rich rocks a rusty-colored weathered surface.

Answer 27

Oxidation

Question 28

the weakening and subsequent disintegration of rock by plants, animals and microbes. Growing plant roots can exert stress or pressure on rock.

Answer 28

Biological/biotic weathering

Question 29

involves hot water rising from below, commonly from volcanic sources, this is the result of interaction of the rock with hot water fluids.

Answer 29

Hydrothermal alteration

Question 30

the chemical replacement of rocks by elements carried in the solution, due to introduction or removal of chemical constituents.

Answer 30

Metasomatism

Question 31

page or leaf-like

Answer 31

Folios

Question 32

No distinct layering character

Often a massive crystalline structure

Formed under uniform pressures

Formed around igneous intrusions where the temperatures are high but the pressures are relatively low and equal in all directions (confining pressure)

Answer 32

Non-foliated metamorphic rocks

Question 33

Rock has distinct banding or layering, often not smooth like in sedimentary rocks

Answer 33

Foliated metamorphic rocks