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Geology GL4 > METAMORHICS > Flashcards

Flashcards in METAMORHICS Deck (22)
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1
Q

At what temperature and depth does diagenesiss occur?

A

5kn 100C

2
Q

D & T metamorphism

A

10-30Km 200C

3
Q

D&T partial melting

A

35-40Km 650C

4
Q

D&T total melting

A

50-100Km 800-1200C

5
Q

What 2 factors cause heat

A

Burial (geothermal gradient)

intrusion of magma will heat adjacent rocks

6
Q

what 2 factors cause pressure

A

Burial

tectonic activicty

7
Q

Describe the 3 groups of matamorphics

A

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

8
Q

What is the identufying charectaristic of reigonal metamorphism?

A

foliation (schistosity or gneissose fabric)

9
Q

Chlorite
hardness-
Colour-
cleavage-

A

2-2.5
dark green
basal cleavage

10
Q

GARNET
Hardness
colour

A

7-7.5

red brown yellow

11
Q

anderlusite
Hardness
colour
cross shaped variety

A

7.5

white red brown orange and green

12
Q
SLATEY CLEAVAGE
What?
Which minerals?
Which direction?
Which rocks?
A

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

13
Q

what are the 3 levels of foliation?

A

slately cleavage, schistosity, baanding

14
Q

Describe slate
Grain size:
foliation:
Minerals:

A

fine spa

15
Q

Whaat is the diference beetween phylite and slate?

A

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

16
Q

what is schistosity?

A

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

17
Q

Describe;
schist-
Blue schist-
Green-schist-

A

biotite muscovie qtz f’spa
glaucophane dominated,
chlorite dominated

18
Q

WHAT IS GNEISS?

A

COARSEST GRAINED BANDED ROCK

19
Q

WHAT IS MIGMATITE?

A
  • metamorphic texture intermixed with igneous

- rock has fractionally melted

20
Q

what is granoblastic texture?

A

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

21
Q

what are isograds?

A

lines of equal metamorphic pressure

22
Q

relative T&P for
Anderlusite
kyanite
siliminite

A

low pressure
low temp high P
high T