METAMORHICS

Question 1

At what temperature and depth does diagenesiss occur?

Answer 1

5kn 100C

Question 2

D & T metamorphism

Answer 2

10-30Km 200C

Question 3

D&T partial melting

Answer 3

35-40Km 650C

Question 4

D&T total melting

Answer 4

50-100Km 800-1200C

Question 5

What 2 factors cause heat

Answer 5

Burial (geothermal gradient)

intrusion of magma will heat adjacent rocks

Question 6

what 2 factors cause pressure

Answer 6

Burial

tectonic activicty

Question 7

Describe the 3 groups of matamorphics

Answer 7

Reigonaal maeamorhism: T&P caused by orogenys or mountain building
Contact: Only T due to intrusions
Dynamic metamorhisn: due to tectonicism

Question 8

What is the identufying charectaristic of reigonal metamorphism?

Answer 8

foliation (schistosity or gneissose fabric)

Question 9

Chlorite
hardness-
Colour-
cleavage-

Answer 9

2-2.5
dark green
basal cleavage

Question 10

GARNET
Hardness
colour

Answer 10

7-7.5

red brown yellow

Question 11

anderlusite
Hardness
colour
cross shaped variety

Answer 11

7.5

white red brown orange and green

Question 12

SLATEY CLEAVAGE
What?
Which minerals?
Which direction?
Which rocks?

Answer 12

Parallel foliation
fine grained platy minerals (chlorite)
perpendicular to main stress
slate and phylitee

Question 13

what are the 3 levels of foliation?

Answer 13

slately cleavage, schistosity, baanding

Question 14

Describe slate
Grain size:
foliation:
Minerals:

Answer 14

fine spa

Question 15

Whaat is the diference beetween phylite and slate?

Answer 15

higher grade metamorohism
similar composition, more chlorites so may be green in colour
thin phylosilicates have formed , unable to see but gives a silky sheen

Question 16

what is schistosity?

Answer 16

a type of layering or foliation found in metamorphic rocks where minerals large enough to be seen by eye line up in the same direction.
Coarse size

Question 17

Describe;
schist-
Blue schist-
Green-schist-

Answer 17

biotite muscovie qtz f’spa
glaucophane dominated,
chlorite dominated

Question 18

WHAT IS GNEISS?

Answer 18

COARSEST GRAINED BANDED ROCK

Question 19

WHAT IS MIGMATITE?

Answer 19

• metamorphic texture intermixed with igneous

- rock has fractionally melted

Question 20

what is granoblastic texture?

Answer 20

equal crystal size, equilibrium conditions. crystals often meet at 120

Question 21

what are isograds?

Answer 21

lines of equal metamorphic pressure

Question 22

relative T&P for
Anderlusite
kyanite
siliminite

Answer 22

low pressure
low temp high P
high T