Flashcards in METAMORHICS Deck (22)
At what temperature and depth does diagenesiss occur?
D & T metamorphism
D&T partial melting
D&T total melting
What 2 factors cause heat
Burial (geothermal gradient)
intrusion of magma will heat adjacent rocks
what 2 factors cause pressure
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
What is the identufying charectaristic of reigonal metamorphism?
foliation (schistosity or gneissose fabric)
red brown yellow
cross shaped variety
white red brown orange and green
fine grained platy minerals (chlorite)
perpendicular to main stress
slate and phylitee
what are the 3 levels of foliation?
slately cleavage, schistosity, baanding
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
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.
biotite muscovie qtz f'spa
WHAT IS GNEISS?
COARSEST GRAINED BANDED ROCK
WHAT IS MIGMATITE?
-metamorphic texture intermixed with igneous
-rock has fractionally melted
what is granoblastic texture?
equal crystal size, equilibrium conditions. crystals often meet at 120
what are isograds?
lines of equal metamorphic pressure