rocks and minerals

igneous

rocks formed from lava/magma

intrusive

• form from magma

• under the surface

• large crystals

• cool slowly

• coarse texture

extrusive

• form from lava

• on the surface

• small/no crystals/airbubbles

• cool quickly

• fine/smooth texture

mafic

ma - magnesium

fic - iron

0 → 45% silica

darker in color

felsic

fel - feldspan

sic - silica

65% → 100% silica

lighter in color

Feldspar

mineral, two types:

• Potassium eg. Orthoclase, sanidine, microcline

• Plagioclase eg. albite→anorthite, richer in sodium and calcium

Porophyr

texture where larger crystals are found embedded within matrix (ground mass)

aphanitic

fine grained

phaneritic

coarsely grained

Bowen’s reaction series

the order in which minerals crystallize

vesicular

rock texture filled with gas bubble cavities

volcanic arc

curved chain of volcanoes formed at subduction zone

geothermal gradient

the increase in temperature in relation to the increase in depth