PHS 111
Test 1 Review Answers
What are the three main layers that make up the earth?
Crust, mantle, core.
What is the most abundant element the earth is made of? Iron
Chapters 20-22
The densest layer is the core.
What are the two most common elements in the earth’s crust?
Silicon and oxygen
Most minerals can be identified by easily observable physical properties. In order of most useful to least useful, the identifiable physical properties are: color, crystal
form, hardness, cleavage, and density; or hardness, cleavage, density, crystal form, and color; or crystal form, color, hardness, cleavage, and
density; or crystal form, hardness, cleavage, color, and density.
The same mineral may exist in a variety of colors.
cleavage; hardness; fracture; bond strength.
What is the hardest mineral on the Mohs scale? (The hardest substance known.) Diamond
Why isn’t color a reliable way to identify minerals?
The property of a mineral to break along planes of weakness is referred to as:
The melting point of silicate minerals is strongly dependent on the amount of silica it contains. The first minerals to melt are those with the: lowest melting point and
lowest silica content; lowest melting point and highest silica content; lowest silica content and highest melting point; highest silica content and
highest melting point.
The precipitation of and crystallization of evaporite minerals is very similar to the crystallization of minerals from a magma. The first evaporite minerals to precipitate
(crystallize) are those with the: lowest solubility; highest melting point; lowest silica content;
highest solubility.
melting and cooling; weathering and lithification.
Igneous, sedimentary, metamorphic. See book for details.
A sedimentary rock can turn into an igneous rock by: compaction and cementation; compaction;
What are the three broad categories of rock and how is each formed?
Mauna Loa (Hawaii) is a: cinder cone;
shield volcano;
composite volcano.
The Earth's temperature increases with depth. Pressure also increases with depth from the weight of the rock above. As pressure increases the: rock above begins to
melt; melting point of the rock (at depth) decreases; melting point of the rock (at depth) also increases; temperature increases, rocks begin to
melt.
If the rock particles in a sedimentary rock are relatively small with well sorted and well rounded grains, we can infer that the sediment grains traveled a: short distance;
long distance for a long time; long distance in a short time; short distance for a long time.
Layers of limestone in a rock outcrop often indicate that the area had at some time been: near the site of volcanic activity; glaciated;
area.
covered by water;
a desert
mechanical weathering; iron oxide stain; lithification.
How does sediment turn into sedimentary rock? The particles of sediment are deposited, one layer upon another. Time and
accumulated periods of further deposition cause the sediments to compact and harden. Fluids interacting with the
sediment act as cementing agents further hardening the sediment into sedimentary rock.
Rocks altered by heat and pressure beneath Earth's surface without melting are: intrusive igneous rocks; extrusive sedimentary rocks; metamorphic rocks;
Ice wedging–freezing of water in cracks–is an example of: chemical weathering;
igneous rocks.
Magma crystallizes under ground.
Motion in a P-wave is: side to side; transverse; longitudinal; up and down.
A seismograph: predicts earthquakes; measures ground movement; helps prevent earthquakes; measures fault displacement.
The speed of a seismic wave depends on: the type of material it travels through; how far it has to travel; its amplitude; its frequency.
Where are plutonic rocks formed?
Earth's internal layers were discovered by studying the propagation of P- and S- waves through Earth's interior. In comparison to P-waves, the movement of S-waves
are: faster and compresses and expands the rock as they move through it; faster and vibrates rock particles up and down and side-to-side; slower and can travel
through solid granite, magma, water or air;: slower and they can only travel through solids, not liquids.
The Earth's magnetic field is attributed to the: flow of molten liquid in Earth's inner core; flow
lithospheric plates in the outer mantle; movement of lithospheric plates at Earth's surface.
of molten fluid in Earth's outer core;
movement of
Continental crust is: thinner than oceanic crust;
less dense than oceanic crust; more dense than oceanic crust; thinner and more dense than oceanic crust.
mantle; outer core.
Continental crust extends farther down into the mantle than oceanic crust because: it is thicker than oceanic crust; oceanic crust is buoyant and rides atop
The asthenosphere is part of the: crust; lithosphere;
the mantle; it is heavier than oceanic crust; it sinks into the mantle and asthenosphere.
The Earth's layer with plastic-like behavior is the:
mantle;
crust; inner core; outer core.
an iron-nickel alloy; calcium magnesium sulfate.
The mantle is composed of: iron and nickel; iron-rich silicate rocks; half liquid and half rocky material; solid rock.
Thermal convection movement in the upper mantle: generates the electric current that powers Earth's magnetic field; greatly influences Earth's surface
features; heats Earth's core by frictional forces; is usually negligible.
The crustal surface and the uppermost part of the mantle is called the: asthenosphere; lithosphere; mohorovicic; centrosphere.
Earth's core is probably composed of: silicate minerals; aluminum oxides;
Compared with oceanic crust, continental crust is very buoyant because it is: composed of basaltic rock that contains air bubbles from successive lava flows;
composed of granitic rocks whereas oceanic crust is composed of basaltic rocks; thinner and forms a thin upper skin on the oceanic
crust below; very young and fresh.
How does erosion and wearing away of a mountain affect the depth to which the crust extends into the asthenosphere?
not extend as deeply into the asthenosphere.
As mountains wear down they do
continental shelves; continental slopes.
was not accepted by the scientific community of
In a reconstruction of Earth's geologic past, the continents of Africa and South America fit best along the: shorelines;
Wegener's theory of continental drift: was first considered a monumental breakthrough in science;
the early 1900's; proved that heat flows convectively below Earth's surface .
Alfred Wegener supported his theory of continental drift by: fitting together the shorelines of the African and South American continents; using paleoclimatic data–
evidence of glaciers in the Northern Hemisphere; paleomagnetic data; making a connection between rocks, rock structures, and plant
and animal fossils found in both Africa and South America.
Describe the theory of continental drift. See textbook.
Detailed mapping of the ocean floors revealed: huge mountain ranges beneath the oceans; deep trenches near some of the continents; that the oceans are equally deep
at all locations; huge mountain ranges on the ocean floor, and deep trenches near some of the continents. the oceans are deepest
at their center.
When the magnetic field of Earth is reversed,: Earth flips over in its orbit; Earth's rotation is also reversed;
newly formed mineral grains on the ocean
floor are magnetized according to the new orientation of the magnetic field.
If the path of polar wandering found from two continents are not the same, then we can say that: Earth's magnetic history has been very complex; at
the continents has moved; our radioactive dating techniques have been inaccurate; the continents have always been widely separated.
How did seafloor spreading suggest a driving force for continental drift? Youngest seafloor is found near continents;
continents; Mantle convection causes irreversible slippage; Subduction creates the youngest seafloor.
least one of
Seafloor spreading pushes
Plate tectonics states that: the continents move through Earth's crust like an icebreaker through ice; earthquakes occur because tectonic plates break like a dropped
dinner plate; tectonic plates have not moved since Pangaea broke up; tectonic plates are in slow, but constant motion.
Tectonic plates are composed of the: crust and mantle;
lithosphere;
Convection in Earth's mantle is attributed to: sinking cold oceanic crust;
between continental and oceanic crust.
lithosphere and the asthenosphere; crust.
gravity and heat flow;
conduction of heat from Earth's core; temperature differences
Plate tectonics differs from continental drift because it: provides a credible driving force; did not explain the fit between South America and Africa;
showed that ancient ice sheets did not exist; showed that Pangaea broke up much later than predicted.
If seafloor spreading creates new lithosphere, does the size of Earth change? Yes, Earth is getting larger; No, the extra crust is crumpled up to form mountains;
older crust is recycled back into the asthenosphere; Yes, the Earth is shrinking because it is cooling.
Regions in which earthquakes are common are also regions in which: hurricanes are common;
fossils are found.
volcanoes are common;
No,
the geomagnetic force is strong; many
on continental land.
tensional forces that stretch the crust and generate a spreading center;
The oldest rocks are found: at convergent boundaries; at divergent boundaries; in the ocean basins;
Divergent boundaries are areas of:
compressional forces that crunch
the crust and generate a spreading center; compressional forces that crunch and shorten the crust by folding and faulting; plate collision.
The dominant force at divergent boundaries is: compression;
tension;
shearing; similar to that in reverse faulting.
Subduction is the process of one lithospheric plate descending beneath another. Why does the oceanic portion of the lithosphere undergo subduction while the
continental portion does not? Oceanic crust is denser.
Each step of 1 on the Richter scale corresponds to a change in energy release of: 2;
The Richter scale measures an earthquake's: frequency;
magnitude;
30;
100; 1000.
damage; all of the above.
The Mercalli scale measures an earthquake's: effects; damage; intensity;
intensity, damage, and overall effect.
Tensional forces cause the crust to: buckle and fold, thereby shortening the crustal surface; buckle and fold, thereby lengthening the crustal surface; stretch and pull,
thereby shortening the crustal surface; break and fracture, thereby lengthening the crustal surface.
Tsunami are correctly referred to as:
seismic sea waves;
tidal waves: energy waves; mega waves.
The Himalayan Mountains formed at which type of plate boundary? Transform-fault boundary; Oceanic-continental convergent boundary; Divergent boundary;
Continental-continental convergent boundary.
Volcanoes do not form at which type of convergent plate boundary? Oceanic—oceanic boundaries; Oceanic—convergent boundaries;
continental convergent boundaries.
Most of Earth's water supply is in the: oceans; ice caps;
Continental—
rivers, lakes, and streams; ground.
oceans; equator.
continents; polar ice caps; oceans; equator.
Most of Earth's fresh water is located in: polar ice caps and glaciers; groundwater; rivers, lakes, and streams; the atmosphere.
Most of Earth's accessible fresh water is located in: polar ice caps and glaciers; groundwater; rivers, lakes, and streams; the atmosphere.
All water–groundwater, surface water, and frozen water–flow downslope in response to: pressure; hydraulic gradient; permeability; gravity.
Sandy soils tend to have: high porosity and high permeability; high porosity and low permeability; low porosity and low permeability;
Evaporation and precipitation are greatest over the: polar ice caps; continents;
Precipitation exceeds evaporation over the:
low porosity and
high permeability.
In a well in an unconfined aquifer, the highest level that water can rise to is:
the well; dependent on how deep the well is.
the level of the water table;
just below the level of the water table; to the top of
soil-moisture.
from where the water table is high to where it is low;
Water in the unsaturated zone is called: groundwater; unsaturated water; pore-water;
The flow of groundwater is: as fast as the water in streams;
to where it is high; insignificant.
from where the water table is low
Rank the following from poorest absorber of water (1) to best absorber of water (4):
rocky surfaces with no soil layer.
(4) sand and gravel, (2) clay, (3) rocky surfaces covered by a soil layer, (1)
porosity; chemical composition;
low permeability; high permeability.
The amount of water able to be contained in the subsurface depends on: permeability;
A soil composed of flattened soil particles will most likely have a:
The water table follows the surface of the ground.
none of these.
True
Land subsidence is caused by: groundwater pumping; clay layers that shrink; gophers;
clay layers.
over-pumping of groundwater and the compaction of
Cave formation in limestone does NOT involve: mildly acidic groundwater; dissolution of carbonate rocks;
Over withdrawal of groundwater causes ground subsidence in areas: of karst topography;
consolidated sediments; all of these
land subsidence; a dropping water table.
underlain by unconsolidated sediments; underlain by
stalactites; stalagmites; dikes.
compacted clay layers cannot be expanded; once pumping is stopped, layers continue to compact;
The formations of rock hanging from the roofs of caves are called: moraines;
Land subsidence is generally not reversible because:
compacted sandy aquifers cannot be expanded; none of the above
Stream velocity is dependent on: the size and shape of the stream's channel; the gradient and stream dimension; gradient and friction;
gradient, channel
geometry, and discharge.
stream with a very steep gradient; canyon.
The volume of water that flows past a given point in a channel during a specified time is called: load: gradient; discharge.
The cross-sectional area and shape of a stream is called: hydraulic gradient; discharge; channel dimension; channel geometry.
Riding down a river in an old canoe, if the discharge of the river does not increase and the river gets very wide and deep, the speed of the river will: decrease;
Stream velocity is faster in a: flat bottomed, shallow stream channel; rounded, relatively deep stream channel;
increase; stay the same; become unpredictable.
widens.
It weathers and erodes sediments, and then
As streams move downslope, channel dimension generally: decreases with decreased discharge; increases with decreased discharge; narrows;
Flowing surface water alters the landscape in what ways? Erosion; Deposition of sediments; Weathering;
it deposits sediment.
Which of the following is characteristic of mountain stream valleys? They are curvy and slow moving;
deltas; They are deep and wide.
In a delta environment the first grains to settle are: light, fine-grained sediment;
and light mixed grains.
They are V-shaped and have rapids;
heavier, coarse-grained sediment;
They have
light, medium-grained sediment; heavy
turbulent; meandering; all of these
the outer side of the meander; the inner side of a meander; both sides of a meander;
The headwater flow of a mountain stream is generally characterized as: laminar;
In a meandering river, erosion is most notable on:
stream channel.
The maximum volume of sediment a stream can carry is dependent on the stream's: laminar flow; velocity;
velocity;
The ability to carry large particle sizes is dependent on the stream's: laminar flow;
discharge;
finer;
channel geometry.
discharge; channel geometry.
Streams transport great quantities of sediment. The most effective transport of sediment occurs in: laminar flow;
flow.
As sediment travels in a downstream river, it changes by getting: coarser;
the bottom of the
turbulent flow;
particle flow; groundwater
more poorly sorted; more angular.
Deltas form as: periodic flooding clogs stream channels; erosion clogs stream channels; stream gradient decreases;
streams enter a standing body of
water.
The work of surface water does all of the following EXCEPT: erosion; deposition;
land subsidence;
delta formation.
downhill due to gravity; northward; toward the Equator.
Chemical weathering, hydraulic action, and abrasion.
Glaciers flow downslope. A glacier moves fastest: when it begins to melt; at its surface and in the center; at its base and along its sides;
Rivers tend to flow: southward;
In what three ways does flowing water erode a stream channel?
when ablation
exceeds accumulation.
Glaciers do not lose mass by:
crevassing;
calving; melting; subliming.
Glaciers will retreat when the amount of accumulation :
equal to the amount of ablation.
is less than the amount of ablation each year;
The typical mountain valley that has been subjected to glaciation is shaped like: a semi-circle;
exceeds the amount of ablation each year; is
the letter "U."; one half of a square; the letter "V."
Glacial deposits are characteristically: well sorted and well rounded; composed of unsorted, angular rock fragments; asymmetrical rock debris.
The most powerful agent of erosion is: stream flow; glacial action; action from waves and ocean currents.
Glacial striations are caused by: rocks embedded in the ice; melting ice.
The principal cause of erosion and transportation of sediment in a desert environment is: wind; caravans; ice; water.
The most important agent of erosion is: water; glaciation; wind; wave action.
The main difference between sand dunes and ripple marks is: ripple marks are only caused by water; ripple marks are larger than sand dunes; sand dunes are
larger than ripple marks; ripple marks are stationary.