Minerology of Melting Flashcards
Flux melting process
as the crust subducts it is metamorphosised and the water molecules move into the asthenosphere, causing melting
as the crust subducts it is metamorphosised and the water molecules move into the asthenosphere, causing melting
Flux melting process
MASH zone
melted asthenosphere pooling at the bottom of the crust, melts the crust and creates a mixture, more mafic minerals precipitate out
melted asthenosphere pooling at the bottom of the crust, melts the crust and creates a mixture, more mafic minerals precipitate out
MASH zone
crust as a filter
as the magma blob rises through the crust, mafic minerals precipitate out, and more felsic minerals are melted in over multiple MASH zone type events. the thicker the crust the more felsic.
lower crust/mantal minerals
Olivine, pyroxenes, and garnet
mid crust minerals
amphiboles (actinilite/hornblende) biotite
upper crust minerals
k-feldspars (Orthocase,microcline, sanidine ) Plagioclase (albite, labradorite, anorthite) Quartz.
controlls the angle of subduction, and therefore where the volcanoes happen
age of subducting plate and speed of plate motion.
age of subducting plate and speed of plate motion.
controlls the angle of subduction, and therefore where the volcanoes happen
M.A.S.H. Zone acronym
Melting, Assimilation, Storage, & Homogenization
Melting, Assimilation, Storage, & Homogenization
Melting, Assimilation, Storage, & Homogenization
Asimilation Fraction Crystalization
AFC, the process by which more mafic minerals crystalize out as more felsic minerals are melted when the magma rises through the crust
AFC, the process by which more mafic minerals crystalize out as more felsic minerals are melted when the magma rises through the crust
Asimilation Fraction Crystalization
Calk-Alkaline chemical trend
as the magma rises through the crust AFC causes magnesium, then iron, to drop out, leaving potassium rich minerals
as the magma rises through the crust AFC causes magnesium, then iron, to drop out, leaving potassium rich minerals
Calk-Alkaline chemical trend
TAS diagram
a graph of alkaline vs silicon content, sectioned off into different rock types
a graph of alkaline vs silicon content, sectioned off into different rock types
TAS diagram
biotite hand sample
black and platy
black and platy
biotite hand sample
Othoclase/sanidine hand sample
good 90 degree cleavage, pearly luster, long grains, presented samples were pink
good 90 degree cleavage, pearly luster, long grains, presented samples were pink
Othoclase/sanidine hand sample
Orthoclase thin section
low relief “Dirty” clear in ppl, 1st order colors with hairy exolution twinning in Xpl
low relief “dirty” clear in ppl, 1st order colors with hary exolution twinningtwinning in Xpl
Orthoclase thin section
microcline thin section
low relief clear in ppl, 1st order colors with CROSSHATCHED lamilar twinning in Xpl
low relief clear in ppl, 1st order colors with CROSSHATCHED lamilar twinning in Xpl
microcline thin section
Albite hand sample
great cleavage, pearly luster, looks like it’s been stacked in layers
great cleavage, pearly luster, looks like it’s been stacked in layers
Albite hand sample
labradorite hand sample
blackish, has that unique labradorescence due to twinning.
blackish, has that unique labradorescence due to twinning.
labradorite hand sample
anorthite hand sample
layered aperence, hard enough to scratch glass
layered aperence, hard enough to scratch glass
anorthite hand sample
Biotite thin section
brown with dramatic prleochroism, (up and down=dark, side to side=light) may have a crinkly texture
brown with dramatic prleochroism, (up and down=dark, side to side=light) may have a crinkly texture
Biotite thin section
