geology test 1 Flashcards
Geology as a science deals with
Great variations in scale and time
A very important concept in geology is that
Earth is constantly changing
Measurements show that climate is changing at an alarmingly fast rate, but the details of the mechanism for the change are still being worked out. Does this make global climate change a Theory, Hypothesis, Observation, Fact, or a completely disproven idea?
Observation
The assumption, presented in your textbook, that the natural world behaves in a consistent and predictable manner that is comprehensible given sufficient study is consistent with which of the following
Uniformitarianism
You have learned that Earth has four important spheres: the Biosphere, Hydrosphere, Atmosphere, and Geosphere. They interact to make the environment we live in. Which of the following geologic features most closely shows the interaction of all four spheres
Soil
Wet mud and earthworms found on the edge of a lake would be considered to be part of
A combination of spheres
“Big Bang” is estimated to have occurred
between 10 billion and 15 billion years ago
The Nebular Hypothesis states that
Earth and the other planets formed at essentially the same time from the same primordial matter as the Sun
Why are the inner planets different from the outer planets
The inner planets contain heavier elements because they were very hot and had a weak gravitational field that could not hold the lighter elements
On Earth, chemical differentiation led to the formation of layers in Earth based on the ______________of the materials that make up those layers
density
What is the major difference between the crust and the mantle?
Composition
If you have a metamorphic rock, and you bury it and heat it until it melts, and then bring it closer to the surface where it cools and solidifies again, the resulting rock would be
Igneous
One of the most important reasons geologists study rocks is
To understand the geological history of Earth
The boundary between the oceanic crust and the continental crust is
in the continental slope
The oldest rocks on Earth would be exposed primarily in the
shields
Ocean floor lies about 3.8 k m (2.4 miles) beneath the sea surface, while continents extend about 0.8 k m (0.5 miles) above the sea surface because
Continents are less dense than ocean floor and both are floating on weak mantle material
The primary difference between Physical and Historical Geology is that
Physical Geology is about the processes that have shaped Earth over time and Historical Geology is about how we can reconstruct the record of change on Eart
Prior to the 1960s, most scientists thought the continents were
Old and stationary
What was the major problem with Wegener’s suggestion that tidal forces could move continents?
Tidal forces are not strong enough to move continents
A plate boundary where one plate is moving under another plate is a _____________ boundary
Convergent
The major difference between the lithosphere and the asthenosphere is
Their behavior. Lithosphere will bend or break, while asthenosphere will flow
The Himalayan mountain range is the result of ___________
A continent–continent collision
What happens at divergent boundaries?
The seafloor spreads and magma rises up to fill the gap, forming underwater features like oceanic ridges and submarine volcanoes
What type of plate boundary is the San Andreas fault zone
Transform
Which of the following Plate boundaries is the least common
Transform
The sediments on the ocean floor get thicker with increasing distance from the ridges because
The seafloor gets older as it moves away from the ridge and so more sediment has time to accumulate farther from the ridge
Which one of these processes does NOT contribute to plate motions
Tidal forces
Which of these locations is located on a divergent boundary
Iceland
The rate of seafloor spreading is typically around
50 mm/yr
Why does subduction occur
Because the oceanic lithosphere becomes more dense than the asthenosphere with age
The three most common volatiles in magma are
Carbon dioxide, sulfur dioxide, and water vapor
Why are lava flows typically finer grained than intrusive igneous rocks
The lava flow cools quickly on the surface of Earth so the mineral grains do not have time to grow
What does texture usually tell us about an igneous rock
How quickly the rock cooled
Glassy igneous rocks form when the magma
cools so fast that mineral grains cannot crystallize and grow
According to Bowen’s Reaction series, which of these minerals will crystallize first
Olivine
A Batholith is
a large group of intrusions that coalesce
Which of the following rocks is likely to have the most quartz within it and why
Granite, because it is an intrusive rock that formed from the cooling of relatively high-silica magma
Decompression melting occurs because
The melting temperature of hot material is lowered as the confining pressure decreases
The chemical equivalent of granite is
Rhyolite
Where does most magma come from
The upper mantle
Bowen’s reaction series is based on
Laboratory experiments involving melting rocks
What is the most important factor for whether magma cools slowly or quickly
The temperature of the environment: higher T = slower magma cooling
What is the difference between primary and secondary magmas
A primary magma is the parent from which the secondary magma forms through differentiation
Sedimentary rocks are particularly important to humans because
They contain resources such as water, oil and gas, uranium, and iron
Which of the following is not a category of sedimentary rocks
Mechanical
Which of the following sedimentary rocks would you expect to have been formed from sediments deposited in a “quiet” environment like a lake or swamp?
Shale
Which of the following sedimentary rocks would you expect to have originally been deposited by fast-moving streams
Conglomerate
If shale is such a common rock in the sedimentary rock world, why isn’t it as prominently exposed at the surface as sandstone
Shale crumbles easily, causing increased mechanical weathering, whereas sandstone resists weathering more effectively
Which of the following sediments would be most likely to give direct information about the type of rocks the particles were derived from
Gravel
Which of the following sedimentary rocks is most likely to have a crystalline texture
Limestone
Which of the following is NOT one of the three major depositional environments
Island
Much of the CO2 in the atmosphere is believed to come from
volcanoes
How does carbon get into the oceans to form the shells of animals?
It combines chemically with water to form H2CO3, which can be reduced to a bicarbonate ion during weathering and transported to the sea
Sandstone is a type of sedimentary rock that is classified based on its
predominant grain size
Petrified wood forms by
the replacement of wood with chert
Dolostone is somewhat of a mystery to scientists because
It is abundant but no marine organisms use it to make shells
Sedimentary rocks are particularly important to humans because
They contain resources such as water, oil and gas, uranium, and iron
Which of the following is not a category of sedimentary rocks
Mechanical
Which of the following sedimentary rocks would you expect to have been formed from sediments deposited in a “quiet” environment like a lake or swamp
Shale
Which of the following sedimentary rocks would you expect to have originally been deposited by fast-moving streams
Conglomerate
If shale is such a common rock in the sedimentary rock world, why isn’t it as prominently exposed at the surface as sandstone?
Shale crumbles easily, causing increased mechanical weathering, whereas sandstone resists weathering more effectively
Which of the following sediments would be most likely to give direct information about the type of rocks the particles were derived from
Gravel
Which of the following sedimentary rocks is most likely to have a crystalline texture
Limestone
Which of the following is NOT one of the three major depositional environments
Island
Much of the CO2 in the atmosphere is believed to come from
volcanoes
How does carbon get into the oceans to form the shells of animals
It combines chemically with water to form H2CO3, which can be reduced to a bicarbonate ion during weathering and transported to the sea
Sandstone is a type of sedimentary rock that is classified based on its
predominant grain size
Petrified wood forms by
the replacement of wood with chert
Dolostone is somewhat of a mystery to scientists because
It is abundant but no marine organisms use it to make shells
What is the main reason the mineralogy of a rock changes during metamorphism
Some minerals are only stable under limited conditions of temperature and pressure, so they change when the conditions change.
Why is it important to know that every metamorphic rock has a parent rock
All metamorphic rocks form from a pre-existing solid rock, and the composition of the parent rock will predict what new minerals will form during metamorphism
What is the most important factor driving metamorphism and why
Heat, because it causes atoms within a mineral to vibrate more rapidly allowing them to migrate more freely
A porphyroblast is
An unusually large mineral that is surrounded by finer grained minerals
Which of the following factors is most likely to produce foliation
Differential stress
Which of the following types of foliated rock is likely to result from the flattening and alignment of micas
Schist
Why do some metamorphic rocks develop a foliation
Because the minerals have distinctly different dimensions in at least two dimensions
The parent rock type for most foliated metamorphic rocks is
Shale
Black smokers are commonly associated with
Ocean crust formed at nearby divergent boundaries
In which setting would regional metamorphism be most likely
At great depths in the crust where two continents are colliding
Which response best represents the conditions of contact metamorphism
Low pressures, shallow burial, and heat supplied by a nearby magma body
If you know the metamorphic facies of a metamorphic rock (example: zeolite), what can you deduce about the rock
Pressure and temperature of formation
In which of the major types of metamorphism does confining pressure play a major role
Burial metamorphism
