Earth- An Introduction to
Physical Geology #2 EXAM
QUESTIONS AND ANSWERS
All rocks are classified according to ________ and
________. - ANSWER-texture and composition
Rhyolite - ANSWER-felsic, extrusive igneous rock
Pumice - ANSWER-felsic, extrusive igneous rock
Gabbro - ANSWER-mafic, intrusive rock
Diorite - ANSWER-phaneritic, intermediate,
intrusive
Andesite - ANSWER-aphanitic, igneous, extrusive,
intermediate
Granite is to - ANSWER-Rhyolite
,Diorite is to - ANSWER-Andesite
Gabbro is to - ANSWER-Basalt
Ultramafic rocks contain __________ and are
commonly found in __________. - ANSWER-
olivine; mantle
What is an accessory mineral? - ANSWER-A
mineral that makes up a relatively small portion
of the total rock composition
Which of the following best describes the
difference between granite and rhyolite? -
ANSWER-Granite is phaneritic and rhyolite is
aphanitic.
What is the rock name of an intermediate rock
with two distinct grain sizes? - ANSWER-Andesite
porphyry
What do pumice and scoria have in common? -
ANSWER-They both exhibit a vesicular texture.
,Which two processes commonly generate
magma? - ANSWER-Decompression melting and
wet melting (the addition of volatiles)
Where does the water involved in melting at
subduction zones come from? - ANSWER-Water
contained within minerals in the subducting plate
is released during metamorphism.
Submit
What is peridotite? - ANSWER-The rock making
up the mantle
Why is water a necessary component of the
melting process in subduction zones? - ANSWER-
The addition of water lowers the melting
temperature of rock
Why is decompression melting common at mid-
ocean ridges but not at subduction zones? -
ANSWER-Tectonic plates are moving apart at
mid-ocean ridges, resulting in a lowering of
pressure beneath the ridge. Tectonic plates are
moving together at subduction zones, resulting in
an increase of pressure under new mountains.
, Which of the following could cause rock to melt?
- ANSWER-increase in temperature
decrease in pressure
change in composition
Which of the following statements best describes
the relationship between pressure and melting
point in the Earth's Interior? - ANSWER-Higher
melting points are determined by higher
pressures.
What role does water play in generating magma?
- ANSWER-Water lowers the melting
temperature of the rock, allowing it to melt.
At a subduction zone, melting is triggered by
_____. - ANSWER-the introduction of water
Submit
How does decompression melting occur? -
ANSWER-When hot, solid mantle rock ascends, it
moves to areas of lower pressure. This reduction
in pressure allows the hot material to melt into a
less compressed liquid phase.
Physical Geology #2 EXAM
QUESTIONS AND ANSWERS
All rocks are classified according to ________ and
________. - ANSWER-texture and composition
Rhyolite - ANSWER-felsic, extrusive igneous rock
Pumice - ANSWER-felsic, extrusive igneous rock
Gabbro - ANSWER-mafic, intrusive rock
Diorite - ANSWER-phaneritic, intermediate,
intrusive
Andesite - ANSWER-aphanitic, igneous, extrusive,
intermediate
Granite is to - ANSWER-Rhyolite
,Diorite is to - ANSWER-Andesite
Gabbro is to - ANSWER-Basalt
Ultramafic rocks contain __________ and are
commonly found in __________. - ANSWER-
olivine; mantle
What is an accessory mineral? - ANSWER-A
mineral that makes up a relatively small portion
of the total rock composition
Which of the following best describes the
difference between granite and rhyolite? -
ANSWER-Granite is phaneritic and rhyolite is
aphanitic.
What is the rock name of an intermediate rock
with two distinct grain sizes? - ANSWER-Andesite
porphyry
What do pumice and scoria have in common? -
ANSWER-They both exhibit a vesicular texture.
,Which two processes commonly generate
magma? - ANSWER-Decompression melting and
wet melting (the addition of volatiles)
Where does the water involved in melting at
subduction zones come from? - ANSWER-Water
contained within minerals in the subducting plate
is released during metamorphism.
Submit
What is peridotite? - ANSWER-The rock making
up the mantle
Why is water a necessary component of the
melting process in subduction zones? - ANSWER-
The addition of water lowers the melting
temperature of rock
Why is decompression melting common at mid-
ocean ridges but not at subduction zones? -
ANSWER-Tectonic plates are moving apart at
mid-ocean ridges, resulting in a lowering of
pressure beneath the ridge. Tectonic plates are
moving together at subduction zones, resulting in
an increase of pressure under new mountains.
, Which of the following could cause rock to melt?
- ANSWER-increase in temperature
decrease in pressure
change in composition
Which of the following statements best describes
the relationship between pressure and melting
point in the Earth's Interior? - ANSWER-Higher
melting points are determined by higher
pressures.
What role does water play in generating magma?
- ANSWER-Water lowers the melting
temperature of the rock, allowing it to melt.
At a subduction zone, melting is triggered by
_____. - ANSWER-the introduction of water
Submit
How does decompression melting occur? -
ANSWER-When hot, solid mantle rock ascends, it
moves to areas of lower pressure. This reduction
in pressure allows the hot material to melt into a
less compressed liquid phase.
