Geology - Metamorphism

Question 1

Metamorphism

Answer 1

The process physical/chemical weathering of rocks with morphological changes.

Question 2

What changes occur from metamorphism?

Answer 2

Chemical composition, mineraology and texture until temperature/pressure equilibrium reached.

Question 3

Where does metamorphosis occur?

Answer 3

10-30km deep and surfaces.

Question 4

Where is metamorphism primaritly?

Answer 4

mid-low crust due to heat and pressure by Earth interior.

Question 5

Metamorphic Grade

Answer 5

Describes the temperature and pressure conditions where metamorphic rocks form

Question 6

What does metamorphic grade increase with?

Answer 6

Pressure/Temperature

Question 7

How does heat transform rock?

Answer 7

Breaking chemical bonds, recrystallising atoms and molecules when surface rocks transported to depths.

Question 8

Geothermal Gradient

Answer 8

The rate of temperature change with increasing depth in Earths interior.

Question 9

Types of pressure rocks experience…

Answer 9

Confined
Directed

Question 10

Confined Pressure

Answer 10

This is applied equally in all directions, increasing with depth with overlyign mass.

Question 11

Directed Pressure

Answer 11

Exerted in a particular direction, as in the convergence of lithospheric plates.

Question 12

Hydrothermal fluids affect on metamorphosis…

Answer 12

Accelerate metamorphosis chemistry, dissolving soluble chemical substances like Na, K and CO2.

Question 13

Types of metamorphism…

Answer 13

Regional
Contact
Seafloor
Shock

Question 14

Hydrothermal Fluids

Answer 14

These are hot groundwaters circulating within Earths crust.

Question 15

Regional Metamorphism

Answer 15

Occurs where there are high temepratures/pressure over large parts of the crust.

Question 16

Contact Metamorphism

Answer 16

Where igneous intrusions metamorphose a rock immediately surrounding it.

Question 17

Seafloor Metamorphism

Answer 17

Is associated with mid-ocean ridges most often, hot basaltic lava spread heats sea water that infiltrates, with convection occuring through the new foreign crust.

Question 18

Shock Metamorphism

Answer 18

Collision of meteorites with Earth where energy transmits heat and shock waves to the rock, potentially producing tekties.

Question 19

Foliation

Answer 19

These form from directed pressure/temperature deforming igneous and sedimentary rocks.

Question 20

Lowest grade of foliation…

Answer 20

Slate

Question 21

Phyllites

Answer 21

Higher metamorphic grade than slate, glossier containing mica and chlorite, split in sheets

Question 22

Schist

Answer 22

Schiscosity derives from high temperatures and pressure subjected onto minerals, where they become more visible and segregate into lighter and darker bands.

Question 23

Gneiss

Answer 23

Have dark and light coloured bands from segregation of amphiboles and quartz/feldspar

Question 24

Migmatite

Answer 24

Mix of igneous and metamorphic rock resulting from partial metling of gneiss.

Question 25

Granoblastic

Answer 25

Rocks with coarse granular appearnace produced by recrystallisation in metamorphism

Question 26

Porphyroblasts

Answer 26

Large crystals having grown in a metamorphic rock

Question 27

Crystallisation

Answer 27

The process where a fluids atoms allign in chemical proportions/arrangements to form a solid substance.

Question 28

Example of a crystal…

Answer 28

Diamond of carbon tetrahedra bound together.