Key workshop terms

Question 1

what are isotropic minerals?

Answer 1

same properties in every direction
Light travels through the mineral with equal velocity in all direction

Question 2

what are anisotropic minerals?

Answer 2

different properties in different directions - most minerals are this type

Question 3

what does it mean if a mineral has high relief?

Answer 3

sharp grain boundaries
Low relief minerals have grain boundaries that are hard to distinguish from each other

Question 4

which mineral grain has low relief?

Answer 4

Quartz

Question 5

what is cleavage?

Answer 5

the tendency for a mineral to break along flat, even surfaces

Question 6

what is birefringence?

Answer 6

the light splits into two rays when it passes through the mineral, and each ray travels at different speeds

Question 7

what causes birefringence?

Answer 7

• Atoms are arranged unevenly inside
  
  • Non cubic minerals - have asymmetrical crystal structures so light doesn’t behave the same in all directions
    Cubic minerals - have symmetrical structures so light behaves the same in all directions

Question 8

what is another name for clastic sed rock?

Answer 8

detrital

Question 9

how do you classify detrital rocks?

Answer 9

• grainsize
• sorting
• roundness
• sphericity of the grains
• textural maturity

Question 10

what is a textural mature rock

Answer 10

well polished and traveled rock
- well sorted
- well rounded
- uniform sizes

Question 11

Foraminers ( small shells) are tiny marine organisms, why are they important?

Answer 11

• important for dating rocks and understanding past climates

Question 12

what are coccoliths?

Answer 12

tiny plate like calcium carbonate pieces
more circular under microscope

Question 13

how do you identify corallites which are a type of coral?

Answer 13

• tubular structures

Question 14

what is folk classification?

Answer 14

a system used to classify carbonate rocks based on the two components
- composition - what the rock is made of
- texture - size and type of grains and matrix

Question 15

what is the dunham classification?

Answer 15

a system for classifying carbonate rocks (mainly limestones) based on their depositional texture, especially **whether the rock was grain-supported or mud-supported when deposited

Question 16

what is twinning?

Answer 16

• When two or more crystals of the same mineral grow together in a symmetrical manner
  Grow in a mirrored pattern

Question 17

what does a well sorted thin section look like?

Answer 17

• grains are all about the same size

Question 18

Matrix vs clast supported?

Answer 18

Matrix supported: contain a significant amount of fine grained matrix material that surrounds and supports the clasts
Clast Supported: have clasts ( pieces of rocks ) that are in direct contact with each other