Geology test 2
How much silica do mafic rocks contain?
44-55%
In what site on this figure would you expect high pressure/low temperature metamorphism?
A and B
Identify the factor(s) that strongly influence the size, shape, and/or sorting of sedimentary clasts.
All of these choices are correct
Under what conditions was this rock likely deformed?
All of these choices are correct
What chemical processes can occur during metamorphism and deformation?
All of these choices are correct
If you were designing a rock that would be easily weathered, which of the following characteristics would it have?
All of these choices are correct.
Which of the following processes produce sedimentary clasts?
All of these choices are correct.
Flood basalts influence life on Earth because:
All of these choices are correct. (large volumes of flood basalts are erupted during a short time; eruptions can release large amounts of gas that cool the atmosphere; eruptions can release large amounts of gas that warm the atmosphere.)
Which of the following are true of felsic magmas?
All these are true of felsic magmas.
Which of the following activities is NOT used to monitor volcanoes?
All these are used to monitor volcanoes.
Which of the following is NOT a rock typically found within calderas?
Gabbro
A coarse-grained intrusive igneous rock composed mostly of feldspar and quartz is called
Granite
On this figure of Bowen's Reaction Series, which mineral would crystallize last from magma?
K-feldspar
The largest concentration of composite volcanoes on Earth is located along the
Pacific Ring of Fire.
How are fissures formed?
Pressure from magma pries open fractures in rock, and then magma fills the fracture.
This image is demonstrating chemical __________ during metamorphism and deformation.
Remobilization
The special geologic terms used to represent the direction of a horizontal line on an inclined surface (like in a fault) and the angle of that surface to the horizontal are
Strike and dip
In this section, a lower gray rock is successively overlain by beach sandstone, lagoon mudstone, and limestone. What is the best interpretation of what was going on?
The area was experiencing a transgression.
What typically happens to the size, shape, and sorting of clasts as they are transported from steep mountains toward more gentle settings?
The clasts become more rounded.
How would the force and stress on the wooden pillar in this figure change if the stone weight was the same size but the wooden pillar were narrower?
The force would remain the same, but the amount of stress would increase.
Which of the following is NOT true about flood basalts?
They are fed from large interconnected composite volcanoes.
Which of the following is NOT a characteristic of a volcanic dome?
They are one of the largest types of volcanoes.
Which of the following are ways that viscosity affects gases in magma?
Viscous magma prevents gas from escaping easily.
What setting was this sedimentary rock deposited in?
a muddy place that sometimes dried out
What type of volcanic eruption is shown in this photograph?
a pyroclastic column
An ophiolite is
a sliced-off piece of oceanic crust that has been thrust onto the edge of a continent or island
Which of the following is the best indicator that a volcano might be very dangerous?
a volcano that contains andesite and welded tuffs
All the following are tectonic settings where large magma chambers can form except
above existing lava fields
Which of the following is a common metamorphic process?
all of these choices are correct
The main source of heat energy for Earth's interior is a direct result of
alpha decay, which is an unstable atom losing 2 protons and 2 neutrons
The most common volcanic rock found in lava flows on composite volcanoes is
andesite.
What type of structure is shown in this figure?
anticline
A fine-grained mafic igneous rock is called
basalt
What type of volcanic eruption is probably shown in this photograph?
basaltic lava flow
If bubbles cannot escape easily from a magma, the resulting eruption is likely to
be explosive
What type of metamorphic feature is shown in this photograph?
cleavage
A relatively large, symmetrical volcano that contains interlayered lava flows, pyroclastic deposits, and volcanic mudflows is a
composite volcano
What kind of metamorphism is occurring in this setting as indicated?
contact
What is the typical setting for fold and thrust belts?
convergent plate boundaries
The igneous feature shown in this figure is a
dike
An igneous rock that solidifies on Earth's surface is a(n)
extrusive rock
What types of rocks would be most common in the volcano in this photograph?
felsic and intermediate lava flows and tephra
The deep-sea floor is characterized by sediment dominated by
fine dust and the remains of single-celled organisms.
Shield volcanoes commonly involve
fluid lava flows
When basaltic lavas reach the ocean they
form pillow basalts
Which of these attributes preserved in sedimentary rocks gives us the most information about past climates?
fossils
Under what conditions was this rock likely deformed?
hot and deep conditions
The geothermal gradient is the
increase of the Earth's temperature with increase in depth
How does the addition of water cause melting?
it changes the location of the liquid-solid boundary
A mantle plume rises because
it is solid but less dense than material around it
The igneous feature shown in this figure is a
laccolith
A sinkhole is most likely to form from dissolution in:
limestone
Long, thin lava flows are typically produced by
low-viscosity lavas
An igneous rock rich in olivine and pyroxene is classified as __________ in composition.
mafic
According to the fossil record, what events have coincided with the approximate times when flood basalts were erupting?
mass extinctions
What type of structure is shown in this figure?
monocline
The transition from the gray shale and limestone to the sandstone and breccia above represents a:
regression
The main cause of melting along subduction zones is the
release of water from the subducting plate
What type of fault is shown in this figure?
reverse fault
The main way water gets into a subduction zone is by
seawater introduced into oceanic crust at the mid-ocean ridge, prior to subduction
What is the plate-tectonic setting of Mount Rainier?
subduction beneath the Pacific Northwest
If a rock is subjected to differential stress, then it means that
the amount of stress is greater in some directions than in others
A lava solidifies into nonvesicular basalt instead of vesicular basalt because
the lava has a low gas content
Which of the rock layers in this figure was most likely deposited by sand dunes on land?
the lowest red sandstone
What does this texture indicate about the formation of this rock?
the magna had abundant dissolved gas
The higher the gas pressure builds in a magma
the more explosive an eruption it is likely to produce.
A porphyritic igneous texture indicates that
the rock cooled slowly and then quickly
A finely crystalline or glassy igneous texture indicates that
the rock was cooled quickly
A vesicular igneous texture indicates that
there was a lot of gas in the magma
Which way was the current (either wind or water) moving during deposition of this section of rocks?
toward the right
Which of the following units was most likely deposited in the deepest marine water?
unit 5
What type of basaltic feature is shown in this photograph?
vesicles
Changes in topography, water chemistry, and gas output all are used to help predict
volcanic eruptions
The relationship between weathering and erosion can best be characterized as
weathering loosens material before erosion carries it away, but erosion can also scour and move unweathered material.
Which of the following attributes does NOT apply to these sediments?
well sorted
Columnar joints, such as the ones shown in the photograph, are formed
when hot but solid igneous rock contracts
