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