MSCI 112 EXAM 2 QUESTIONS VERIFIED ANSWERS
large igneous provinces are thought to be the result of ________ volcanism - Answers -
intra-plate superplume
in the atlantic ocean region, where are most of the active volcanoes located? - Answers
- along the mid-atlantic ridge
during volcanic eruptions pieces of the country rock wall can be broken off and brought
up in the eruption. which deposit is most like to contain such fragments? - Answers -
breccia
basaltic lava that cools under water forms distinct ______ features - Answers - pillow
lava
magma generated in earth's interior rises because its _____________ than the
surrounding rocks - Answers - less dense
over the past 2000 years, which of the following volcanic hazards has caused the most
fatalities? - Answers - pyroclastic flows
which of the following is least likely to signal an impending volcanic eruption - Answers -
tsunamis
one hypothesis proposes that large igneous provinces form at hot spots by mantle
plumes that originate at what boundary within earth - Answers - mantle-outer core
boundary
what types of lavas are erupted at mid-ocean ridges - Answers - basalts
huge mudflows made up of wet volcanic debris - Answers - lahars
where on earth are volcanoes typically found - Answers - subduction zones, spreading
centers, such as mid-ocean ridges, hot spots, and mantle plumes
what types of volcanic eruptions are found at subduction zones? what types of rocks are
found there? - Answers - at subduction zones they have magma that is produced by
fluid- induced melting. they produce andesitic rock, new continental crust.
type of magma typically associated with explosive eruptions - Answers - rhyolitic
magmas: have lower melting temp and richer in silica making most viscous.
, why does rhyolitic magmas produce explosive eruptions - Answers - flows slow and has
a tendency to build up where gases can easily become trapped below the lavas
how do volcanoes affect atmosphere and climate - Answers - change the composition
and properties of atmosphere by eruptions that inject sulfurous gases into the
atmosphere. eruptions create aerosols that block the suns radiation, making global
temps lower. debris can affect crops that fall. greenhouse effect.
volcano is basically a hill or mtn made of - Answers - lava and other erupted material
types of lava - Answers - basaltic: (1000-1200)
aa
pahoehoe
pillow lava
andesitic (<1000)
rhyolitic (600-800)
texture of volcanic rock - Answers - vesicles (bubble holes)
glassy texture (no crystals)
pyroclasts (broken pieces)
what are in pyroclastic deposits - Answers - volcanic ejecta (ash, bombs)
pyroclastic flows (tuffs- rocks created from smaller fragments and breccia- formed from
larger fragments)
landforms of volcanoes - Answers - shield, dome, cinder cone, stratovolcano, caldera,
diatremes
stratovolcano - Answers - alternating layers of pyroclasts and lava flows.
solidified lava in central channel and surrounding dikes, strengthens. common over
subduction zones
craters - Answers - smaller and form in the central vent after an eruption
caldera - Answers - much larger and form due to the collapse of the empty magma
chamber
eruptions from linear cracks form - Answers - fissure eruptions
flood basalts
ash-flow deposits
fumaroles - Answers - where volcanoes emit steam and other gases through vents after
a major eruption
hydrothermal activity - Answers - circulation of water through hot volcanic rocks and
magmas
large igneous provinces are thought to be the result of ________ volcanism - Answers -
intra-plate superplume
in the atlantic ocean region, where are most of the active volcanoes located? - Answers
- along the mid-atlantic ridge
during volcanic eruptions pieces of the country rock wall can be broken off and brought
up in the eruption. which deposit is most like to contain such fragments? - Answers -
breccia
basaltic lava that cools under water forms distinct ______ features - Answers - pillow
lava
magma generated in earth's interior rises because its _____________ than the
surrounding rocks - Answers - less dense
over the past 2000 years, which of the following volcanic hazards has caused the most
fatalities? - Answers - pyroclastic flows
which of the following is least likely to signal an impending volcanic eruption - Answers -
tsunamis
one hypothesis proposes that large igneous provinces form at hot spots by mantle
plumes that originate at what boundary within earth - Answers - mantle-outer core
boundary
what types of lavas are erupted at mid-ocean ridges - Answers - basalts
huge mudflows made up of wet volcanic debris - Answers - lahars
where on earth are volcanoes typically found - Answers - subduction zones, spreading
centers, such as mid-ocean ridges, hot spots, and mantle plumes
what types of volcanic eruptions are found at subduction zones? what types of rocks are
found there? - Answers - at subduction zones they have magma that is produced by
fluid- induced melting. they produce andesitic rock, new continental crust.
type of magma typically associated with explosive eruptions - Answers - rhyolitic
magmas: have lower melting temp and richer in silica making most viscous.
, why does rhyolitic magmas produce explosive eruptions - Answers - flows slow and has
a tendency to build up where gases can easily become trapped below the lavas
how do volcanoes affect atmosphere and climate - Answers - change the composition
and properties of atmosphere by eruptions that inject sulfurous gases into the
atmosphere. eruptions create aerosols that block the suns radiation, making global
temps lower. debris can affect crops that fall. greenhouse effect.
volcano is basically a hill or mtn made of - Answers - lava and other erupted material
types of lava - Answers - basaltic: (1000-1200)
aa
pahoehoe
pillow lava
andesitic (<1000)
rhyolitic (600-800)
texture of volcanic rock - Answers - vesicles (bubble holes)
glassy texture (no crystals)
pyroclasts (broken pieces)
what are in pyroclastic deposits - Answers - volcanic ejecta (ash, bombs)
pyroclastic flows (tuffs- rocks created from smaller fragments and breccia- formed from
larger fragments)
landforms of volcanoes - Answers - shield, dome, cinder cone, stratovolcano, caldera,
diatremes
stratovolcano - Answers - alternating layers of pyroclasts and lava flows.
solidified lava in central channel and surrounding dikes, strengthens. common over
subduction zones
craters - Answers - smaller and form in the central vent after an eruption
caldera - Answers - much larger and form due to the collapse of the empty magma
chamber
eruptions from linear cracks form - Answers - fissure eruptions
flood basalts
ash-flow deposits
fumaroles - Answers - where volcanoes emit steam and other gases through vents after
a major eruption
hydrothermal activity - Answers - circulation of water through hot volcanic rocks and
magmas
