magma differentiation

Question 1

what is magmatic differentiation

Answer 1

formation of different rock types from a single magma comp

Question 2

3 main magmatic differentiation process

Answer 2

fractional crystallisation

crustal contamination (or crustal assimilation)

magma mixing

Question 3

what is fractional crystallisation

Answer 3

when melts and crystals separate during crystallization

Question 4

how does fractional crystallisation happen

Answer 4

3 ways:

crystal settling

crystal flotation

filter pressing

Question 5

crystal settling

Answer 5

dense crystals sink to bottom of magma forming solid layer of crystals covered by melt of different comp

Question 6

crystal flotation

Answer 6

crystal less dense than melt float to the top

Question 7

filter pressing

Answer 7

magma squeezed through small opening, such as a fracture, and a crystal clog the opening so only melt can pass through

Question 8

crustal contamination (or crustal assimilation)

Answer 8

solid pieces of country rocks with different, often felsic, with different comp are added into the magma. foreign rock either:

-melt changing comp of original magma
-or remain intact within cooling magma and only partially melted.

form xenoliths

Question 9

magma mixing

Answer 9

two different magma come into contact and mix

forms enclaves (inclusions) in rock or banding in rock

either homogeneous forming an intermediate rock or not preserving both rocks