ENVS 212 metamorphism - lecture 1 metamorphism in the field and in the lab

What is an index mineral?

Minerals used as markers for specific conditions

What is a mineral assemblage?

The combination of minerals found in a given rock

What is metamorphism?

Any mineral and or textural change induced by pressure and or temperature and or fluids in the mainly solid state

What 2 minerals make up albite?

Jadeite and quartz

What is a stability field?

The range of pressures and temperatures where a polymorph is stable

What is a polymorph?

Minerals that have the same composition but a different structure/arrangement

What is the cause of contact metamorphism?

Heat from a nearby intrusion

What pattern are the zones in contact metamorphism?

Concentric (follows the intrusion boundary in 3D)

Is the pressure variable or fixed in contact metamorphism?

Fixed

Is deformation likely in contact metamorphism?

No

Roughly how big is the affected area in contact metamorphism?

1km

What is a characteristic feature that indicates contact metamorphism?

Metamorphic aureole

What scale does regional metamorphism occur at?

100s to 1000s km

What 2 variables vary in regional metamorphism?

Temperature and pressure

Is deformation likely to occur during regional metamorphism?

Yes

What major event is regional metamorphism associated with?

Collision plate boundaries

Give an example of where hydrotherapy metamorphism occurs?

MORs

What is hydrothermal metamorphism caused by?

Hot circulating fluids

What is dynamic metamorphism caused by?

Deformation

What type of changes occur in dynamic metamorphism?

Textural

What 3 minerals typically make up impure limestone?

Calcite, silica and dolomite

Give an example of a sedimentary polymorph?

Calcite and aragonite

What is a protolith?

The original rock before it undergoes metamorphism

What mineral is diopside a type of?

Clinopyroxene

What mineral is tremolite a type of?

Amphibole

What are the 3 polymorphs of Al2SiO5?

Kyanite, sillimanite, andalusite

Order the clay polymorphs from least dense/lowest pressure to most dense/highest pressure?

Andalusite, sillimanite, kyanite