Metamorphic changes occur
at the solid state
Bedding
sedimentary layering rocks
Metamorphic foliation
layering of metamorphic rocks, parallel alignment of platy minerals
Igneous rock
freezing of a melt
Pressure prevents
melting
Decompression melting
occurs when mantle rock rises to the shallower depths of the earth
Adding volatiles to hot mantle rock
creates melting
Magma rising from the mantle into the crust
transfers heat and creates melting of the crustal rock
Magma is made from what tetrahedron?
Silicon-oxygen
Magma atoms are aligned in
short chains or small clusters
Mafic magma has high amounts of
iron oxide and magnesium oxide
Magma viscosity depends on
temperature, volatile content, and silica content
Factors controlling the cooling of magma:
the depth of intrusion, the shape and size of a magma body, the presence of circulating ground water
Dike
tubular intrusion that cuts across preexisting layering
Sill
tubular intrusion that injects parallel to layering
Small grain size means
quicker cooling rate
Mafic rocks are
solid black to dark grey
Felsic rocks are
light tan, pink, or maroon
Silica poor basaltic lava is
less viscous
pahoehoe
smooth, glassy, ropelike ridges
a'a'
jumbled sharp angular fragments
Lahar
watery ash mixture that flows down the side of volcanoes
Caldera
big circular depression caused by the emptying of a magma chamber
Flood basalt
sheets of low viscosity lava
Weathering
breaking down of rock into sediment
Clastic sedimentary rocks
solid fragments cemented together
Deposition
sediment settles out of transportation material
Breccia
large pieces of jagged rock cemented together
Conglomerate
burial and lithification of rounded breccia
Foliation
layered light and dark bands
Phylite has
very fine grained mica
Schist has
large grained mica
Non-foliated metamorphic rocks
hornfels, quartzite, marble
Low temperature metamorphic rocks are
low grade
High temperature metamorphic rocks are
high grade