exam 2: igneous rocks

give an example of a LIP in the continental US

Columbia River Flood Basalts

which of the following rocks display a stunning black glassy texture

obsidian

extrusive igneous rock textures can be

glassy or aphanitic texture

why does molten rock move upward through the earth's mantle

molten rock is less dense than the surrounding solid rocks

a vesicular texture is one in which

pores are abundant

another name for fragmental texture is

pyroclastic texture

bowens reaction series

shows that as magma crystallizes, the remaining melt is depleted in silica

pyroclastic flow occurs in

extrusive settings

all aphanitic textures are

fine grained, derived from lava, cooled faster

dikes and sills are

high angle and low angle igneous intrusions

vesicles in vesicular textures are remnants of

volatile passages in an igneous rock

fragmental texture is formed from

volcanic ash and volcanic rock debris

which of the following pairs of minerals are part of the continuous reaction series in Bowens Reaction Series?

Ca rich plagioclase and Na rich plagioclase

dikes and sills

High angle and low angle igneous intrusions

intra plate volcanism is seen at

Hotspots

flood basalts are characteristic of

LIPs

composition of the earths mantle is

Mafic to ultramafic

in a flux induced melting, which of the following can act as a flux

Water vapor, carbon dioxide, sulfur dioxide

which of the following words may be used to describe portions of rock with porphyritic texture

aphanitic, phenocrysts, groundmass

which of the following melt compositions do you expect to travel long distances

basalt melts

two magma chambers of similar size are undergoing crystallization. chamber a is tabular. chamber b is spherical. which chamber cools faster

chamber a

two magma chambers of similar size are undergoing crystallization. chamber x is 10 km below the earth's surface. chamber y is 50 km below the earth's surface. which chamber cools slower?

chamber y

all phaneritic textures are

coarse grained, derived from magma, cooled slowly

list three tectonic/ mantle processes that trigger decompression melting

continental rift valleys, mid ocean ridges, and mantle plumes

mafic igneous rocks tend to have

darker color shades

what kind of melting do you expect in a continental rift tectonic setting

decompression melting

what kind of melting do you expect just under a mid ocean ridge

decompression melting

give an example of a place currently undergoing continental rifting

east african rift valley

what kind of melting do you expect at subduction zones

flux induced melting

a course grained magmatic igneous rock with 65% SiO2 and containing minerals like quartz, K- feldspar may be called

granite

porphyritic rocks are named for the size of

groundmass grains

give an example of a location experiencing a hot spot induced volcanism

hawaii

a dike intrudes into

igneous, sedimentary, and metamorphic rock

a porphyritic texture is one in which

individual crystals are a mix of coarse and fine grained crystals

a phaneritic texture is one in which

individual crystals can been seen with the naked eye

a aphanitic texture is one in which

individual crystals cannot be seen with the naked eye

a porphyritic textures indicate

initial slow cooling and then fast cooling

felsic magma

is more viscous than mafic magma

LIP is

large igneous provinces

hot rock melt on the earth's surface is called

lava

felsic igneous rocks tend to have

lighter color shades

what kind of igneous rocks do you expect at mid ocean ridges

mafic fine grained

hot rock melt inside the earth is called

magma

which of the following minerals crystallize via the discontinuous reaction series

olivine, pyroxene, amphibole

what is the primary factor that keeps the mantle rocks from melting at very high termperatures of ~3000 degrees C

overburden pressure

all intrusive igneous rocks have

phaneritic texture

coarse grained crystals in porphyritic textures are called

phenocrysts

list the 4 tectonic setting where igneous activity occurs

subduction zones, mid ocean ridges, continental rifts, hot spots

which of the following rocks is not derived from an igneous rock melt

tuff

an igneous rock containing <45% SiO2 is called

ultramafic rock

which of the following melt compositions are arranged in the order of increasing viscosity

ultramafic<mafic<intermediate<felsic

which of the following melt compositions are arranged in the order of increasing volcanic explosivity

ultramafic<mafic<intermediate<felsic

a magma that is rich in volatiles is called

wet magma