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Flashcards in METAMORHICS Deck (22)
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1

At what temperature and depth does diagenesiss occur?

5kn 100C

2

D & T metamorphism

10-30Km 200C

3

D&T partial melting

35-40Km 650C

4

D&T total melting

50-100Km 800-1200C

5

What 2 factors cause heat

Burial (geothermal gradient)
intrusion of magma will heat adjacent rocks

6

what 2 factors cause pressure

Burial
tectonic activicty

7

Describe the 3 groups of matamorphics

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

8

What is the identufying charectaristic of reigonal metamorphism?

foliation (schistosity or gneissose fabric)

9

Chlorite
hardness-
Colour-
cleavage-


2-2.5
dark green
basal cleavage

10

GARNET
Hardness
colour


7-7.5
red brown yellow

11

anderlusite
Hardness
colour
cross shaped variety


7.5
white red brown orange and green

12

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


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

13

what are the 3 levels of foliation?

slately cleavage, schistosity, baanding

14

Describe slate
Grain size:
foliation:
Minerals:


fine spa

15

Whaat is the diference beetween phylite and slate?

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

what is schistosity?

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

Describe;
schist-
Blue schist-
Green-schist-


biotite muscovie qtz f'spa
glaucophane dominated,
chlorite dominated

18

WHAT IS GNEISS?

COARSEST GRAINED BANDED ROCK

19

WHAT IS MIGMATITE?

-metamorphic texture intermixed with igneous
-rock has fractionally melted

20

what is granoblastic texture?

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

21

what are isograds?

lines of equal metamorphic pressure

22

relative T&P for
Anderlusite
kyanite
siliminite


low pressure
low temp high P
high T