UD Geol105 Exam #2
___ states that the velocity of ground water equals permeability multiplied by hydraulic gradient.
Darcys law
A worldwide decrease of at least _____°C in temperature would bring about a new glacial age.
5
What is the gradient of a stream that drops 10 vertical feet over a 2-mile horizontal distance?
5 ft per mile
What is a sea stack?
A sea stack is a pillar of rock that is cut off from the headland or cliff.
The ______ load is sediment light enough to remain lifted indefinitely above the bottom by water turbulence.
suspension
How fast groundwater flows depends, in part, on the permeability of the sediment through which it passes.
true
Longshore currents transport most of the beach sand parallel to the shoreline.
true
Point bars are sandbars deposited in the middle of river channels.
true
Rapid down cutting of desert stream channels produces narrow canyons with vertical walls and flat gravel-strewn floors.
true
Sheetwash is a thin layer of unchanneled water flowing downhill.
true
Springs may form where a perched water table intersects the surface.
true
Striations and grooves in bedrock indicate the direction of ice movement.
true
Support is growing for the idea that a late Precambrian ice sheet was so extensive that the surface of the world ocean was frozen.
true
The Basin and Range province is characterized by rugged mountain ranges bounded by faults.
true
The capillary fringe is thicker in fine-grained sediments and thinner in coarse-grained sediments.
true
The process of deepening a valley by erosion of the streambed is called downcutting.
true
The rate of ground water flow tends to decrease with depth because sedimentary rock pores tend to be closed by increasing amounts of cement and the weight of the overlying rock.
true
The saturated zone overlies the water table.The capillary fringe is thicker in fine-grained sediments and thinner in coarse-grained sediments.
true
The site selected for the disposal of high level radioactive waste is the ocean.
true
The world's best-known deserts lie in a belt 10-15 degrees centered at latitude of 30 degree (North and South).
true
Thin rocky soil and slow rates of creep make desert topography steep and angular.
true
Tillite is lithified till.
true
Unsorted and unlayered rock debris carried or deposited by glaciers is called till.
true
Water in the upper part of the saturated zone tends to move downward following the slope of the water table.
true
When water is pumped from a well the water table is typically drawn down into a zone of depression.
true
Where glaciers exist they are far more effective agents of erosion, transportation, and deposition than running water.
true
Where sand supply is limited a barchan dune generally develops.
true
Two layers of sediment resulting from one year's deposition in a glacial lake are called ___.
varves
Stream erosion and deposition are controlled primarily by a river's
velocity
Rocks with flat, wind-abraded surfaces are called
ventifacts
Deltas may be river dominated, tide dominated or _____.
wave dominated
Coastal straightening occurs because of ____.
wave erosion of headlands and deposition in bays
The diameter of the orbital path of a water particle near the surface is equal to _____.
wave height
The vertical distance between the crest and the trough of a wave is called the ____.
wave length
The bending of waves as they enter shallow water is called _____.
wave refraction
A _____ is a deep, cylindrical hole that is dug or drilled into the ground to penetrate an aquifer within the saturated zone.
well
In unconfined aquifers water in shallow wells __.
will rise to the level of the water table
The upper part of a glacier, the part with perennial snow and ice, is called the __.
zone of accumulation
Glacially carved valleys are usually _____ shaped.
U
Precipitation that does not infiltrate the ground is runoff that may move unchanneled as ______
a rill
Rock debris picked up in flash floods is deposited at the base of mountains in ____.
alluvial fan
A river's velocity is faster ____.
along the outside of a meander loop near the cut bank
A(n) _______ is a body of saturated rock or sediment through which water can move easily.
aquifer
Which of the following would not be a control on desert development?
areas beneath rising air masses
Sharp ridges called ___ separate adjacent glacially carved valleys.
aretes
Desert stream channels called ____ are characterized by narrow canyons with vertical walls and flat, gravel-strewn floors.
arroyos
In a(n) _____ aquifer water rises above the top of the aquifer when a drill penetrates it.
artesian
Flood control structures along the Mississippi River surrounding New Orleans are predominantly _____.
artificial levees
A _____ is a ridge of sediment built by sedimentation on the middle or banks of a stream channel.
bar
types of dunes?
barchan transverse parabolic longitudinal
Which would characterize a depositional coast?
barrier islands
The steepest part of a beach is the ____.
beach face
Most caves are probably formed by ground water circulating ___ the water table.
below
A ______ is a narrow hill of resistant rock with a flat top and very steep sides found in some deserts.
butte
_____ form when slightly acidic ground water dissolves limestone along joints and bedding planes.
caves
___ influences the velocity of a river along with gradient.
channel shape and roughness
_______ has extensive loess deposits up to 100 meters thick.
china
A(n) ______ is a steep-sided half-bowl shaped recess carved at the head of a mountain glacial valley.
cirque
Hurricanes are associated with all the following except ______.
clockwise rotation in the Northern Hemisphere?
A ___ encompasses all land near the sea, including the beach and a strip of land inland from it.
coast
This area of the desert southwest is characterized by mostly flat-lying beds of sedimentary rock over 1,500 meters above sea level.
colorado plateau
A(n) _________ aquifer is completely filled with water under pressure and is separated from the surface by an aquitard.
confined
Streams in rainy regions tend to be ______ the saturated zone; as such, we call them ______ streams.
connected to; gaining
In North America, the ___ separates streams that flow into the Pacific Ocean from those that flow into the Atlantic Ocean and Gulf of Mexico.
continental divide
The removal of clay, silt, and sand particles from the land surface by wind is called
deflation
A(n) ___ drainage pattern of a river resembles a tree.
dendritic
U.S. coasts with gently sloping plains, such as those along the Atlantic and Gulf of Mexico, are ____.
depositional
When water is pumped out of an unconfined aquifer through a well, a ___ often develops in the water table.
depression
The Atacama Desert in western South America is created by ______.
descending dry air
_______ is a thin surface layer of closely packed pebbles found in deserts.
desert pavement
The expansion of deserts into once populated areas is known as ___.
desertification
A ridge or strip of ground separating one drainage basin from another is termed a ____.
divide
The process of deepening of a valley by erosion of a streambed is called __.
down cutting
The ______ is the total area drained by a river and its tributaries.
drainage basin
The total area drained by a stream and its tributaries is called the
drainage basin
Heavy use of ground water can cause a region's water table to ____.
drop to deeper depths
Bodies of till shaped into streamlined hills are called ___.
drumlins
The hydraulic head is defined as __.
elevation plus pore fluid pressure at a given point
The boundary between the zone of accumulation and the zone of ablation is an irregular line called the _____.
equilibrium
The boundary between the zone of accumulation and the zone of ablation of a glacier is called the
equilibrium line
Hydraulic action, solution, and abrasion are all examples of stream
erosion
Look at the "S" shapes in the middle-lower half of the photo below. Which of the following is a true statement based on what we know about streams? (Select all that apply.)
erosion is higher outside of bends sediment is probably fine salt and silt stream flowing top to bottom
A(n) ___________ is an ice-transported boulder that was not derived from the underlying bedrock.
erratic
Which is not a type of moraine?
esker
Water in the atmosphere turns from a gas into a liquid by the process of ______.
evaporation
Water moves from surface water into the atmosphere through ______.
evaporation
A playa lake is a deep long-lasting desert lake.
false
An end moraine marks the final edge of a receding glacier just before the glacier melts away entirely.
false
An irregular coast with bays separated by headlands can be straightened by plate tectonic forces.
false
Drainage basins are bowl-shaped depressions with a lake in the middle, and all streams in the basin discharge their water and sediment into that lake.
false
Estuaries, such as Chesapeake Bay, are drowned glacial-cut valleys.
false
Glaciers in temperate climates may have crevasses that extend to their base.
false
Low stream velocity generally results in erosion and transportation of sediment.
false
More sand is moved along the beach face than in the surf zone.
false
Paved areas and storm sewers decrease the rate of surface runoff of water.
false
Petrified wood develops when buried wood is saturated or replaced with calcite.
false
Sandstones and gravels make the only aquifers; no other rocks are useful.
false
Since many desert regions have internal drainage, runoff collects on the valley floors as bajadas.
false
Stream discharge is one of the most important factors that controls stream velocity.
false
Stream-dominated river deltas, like the Mississippi, display the characteristic triangular shape of a delta.
false
The interrelationship of the hydrosphere, geosphere, biosphere, and atmosphere is visualized through the hydrogeologic cycle.
false
The saturated zone overlies the water table.
false
The thicker part of a glacier will flow slower than where it is thinner.
false
Ventifacts are rocks with rounded water-abraded surfaces.
false
Wave orbits decrease in size until motion is gone at a depth equal to twice wavelength.
false
Waves usually come straight into shore.
false
How fast does the central part of a valley glacier move compared to the sides of the glacier?
faster
A large trunk glacier carves a deeper valley than smaller tributaries. After the glacier disappears the tributary valley remains as _____ high above the main valley.
hanging valley
A valley glacier that ______ will tend to move faster than one that does not.
has a thin film of water at its base
Some _____ beaches are made up of sand-sized particles of basalt.
hawaii
Waves break because:
height increases while length decreases
Streams erode rock and sediment by ___.
hydraulic action, solution, abrasion
Ordinary ocean waves are created by the interaction of the ____ and ____.
hydrosphere, atmosphere
During the Ice Ages, much of Nevada, Utah, and eastern California was covered by
ice
A(n) _______ is a mass of ice that is not restricted to a valley but covers large areas of land.
ice sheet
If a moving glacier reaches a body of water ______ float free.
icebergs
An _____ rock is one that does not allow water to flow through it easily.
impermeable
_____ meanders are meanders that retain their sinuous pattern as they cut vertically downward below the level at which they originally formed.
incised
When we refer to water as being "hard", we really mean that ______.
it has a lot of dissolved calcium and magnesium in it
Given all other conditions are the same, ground water flows faster if __.
it is flowing in response to a greater hydraulic gradient
Much of the southwestern United States is desert because (choose as many as apply)
it is near 30° North the western mountains create a rain shadow cold ocean currents in the Pacific cause high evaporation rates in the land
____ are rock walls designed to protect the entrance of a harbor from sediment deposition and storm waves.
jetties
When an ice block that was buried in sediment finally melts, a depression called a ___ forms.
kettle
A barrier island is typically separated from the mainland by a ______.
lagoon
A graded stream can be deepening its channel by down cutting while part of its energy is also widening its valley by ______ erosion.
lateral
_______ dunes in the Sahara are as high as 200 m and as long as 120 km.
longitudinal
_____ is the movement of sand parallel to the shore.
longshore drift
In very dry climates such as deserts, rivers tend to be __.
losing streams
The amount of ground water is ____ that of all rivers and lakes combined.
many times
Rivers may develop pronounced sinuous (wiggly) curves called a ___ pattern.
meandering
Where tributary glaciers come together the adjacent lateral moraines join to form a ______ moraine.
medial
The sea level rise in the past 15,000 years is due to ____.
melting glaciers
In the United States, large areas of _____ are blanketed with a cover of loess.
midwest
_____ are low ridges of flood deposited sediment that form on either side of a stream channel and thin away from the channel.
natural levees
________ are low ridges of flood-deposited sediment that form on both sides of a stream channel and thin away from the channel.
natural levees
The Geysers is a power plant in California that generates electricity ______.
naturally hot water? flowing groundwater?
The Basin and Range province covers almost all of
nevada
The sediment deposited by debris-laden melt water is called _______.
outwash
A cutoff meander may become a crescent-shaped __.
oxbow lake
A ____ dune is deeply convex and its horns point upwind.
parabolic
You can get out of a rip current easily by swimming ____ to the beach instead of struggling against the current.
parallel
Recently, geologists have been drilling through ice sheets for clues about
past climates on earth
Shales can have substantial porosity but have low _____.
permeability
________ refers to the ability of a rock to transmit fluids.
permeability
A very flat surface underlain by a dry lake bed of hard, mud-cracked clay is called a
playa
Sandbars deposited on the inside of meander curves are called
point bars
___ is the percentage of a rock or sediment that consists of void space.
porosity
Choose the Moon position that would cause a spring tide (higher than normal high tides and lower than normal low tides) in North America (North America is on the sunlit side of the globe).
position one
A ____ drainage pattern is one in which streams diverge outward likes spokes on a wheel.
radial
If the terminus of a glacier remains stationary for a few years a distinct _______ may form.
recessional moraine
Which is not a drainage pattern?
rectangular
The average time between floods of a given size is
recurrence interval
______ are narrow currents that flow straight out to sea in the surf zone.
rip currents
If all ice sheets were to melt, sea level would _____.
rise over 60
The greater part of the sand from most beaches comes from ____.
rivers
The grinding of rock against rock by a glacier produces a very fine sediment called ____.
rock flour
_____ refers to sand grain movement in a series of short leaps or bounces off the bottom.
saltation
Heavily pumped wells near a coast can be contaminated by ____.
saltwater intrusion
Which of the following earth materials would you expect to have the lowest permeability?
sandstone
Which rock type would make the best aquifer?
sandstone
____ are closed depressions found where land surfaces are underlain by limestone bedrock.
sinkholes
The major difference between a mesa and a butte is one of
size
The steep downwind face of a sand dune is called the ______.
slip face
Sediment may build up off a point of land to form a ____.
spit
A ________ is a place where water flows naturally from rocks onto the ground surface.
spring
A "100-year flood" has a _______ percent chance of occurring in any given year.
1%
The last episode of extensive glaciation in North America was at its peak about _____ years ago.
10000
A deposit of loose sand may have a porosity of _____ percent.
30-50
In parts of Texas and New Mexico the pumping of ground water has caused the water table of the Ogallala Reservoir to drop ____.
30m
Select the possible effects urbanization can have on stream aside from "flashy" behavior. (Select all that apply.)
More pavement which can prevent rainwater from soaking into the ground More rain falls in rural areas
Which of the following does not describe the process of plucking?
Pieces of rock fall onto the top of the glacier.
What is firn?
The transitional phase between snow and glacial ice
What would happen to the velocity of a river if an avalanche dumped rocky debris on its stream bed?
The velocity would decrease because the channel roughness had increased.?
_____ are wave cut platforms formed by erosion of rock associated with cliff retreat.
Uplifted marine terraces
Under the influence of gravity a glacier moves down valley and eventually __.
ablates
A(n) ___ stream flows in a network of rivulets (subchannels) around numerous sandbars.
braided
A stream can increase its length by _____.
building a delta, meandering, and headward erosion
On large alluvial fans, the _____ sediment is deposited near the mountains.
corseset
Open fissures called ___ develop in the brittle surface ice of glaciers.
crevasses
What typically happens to the gradient of a river from its headwaters to its base?
increases?
Gasoline leaking from an underground storage tank will __.
infiltrate to the top of the water table, on which it will float
A large dune type is the _______ (or seif) dune, which forms a ridge parallel to prevailing wind direction.
longitudinal
Vast amounts of sand are moved by ____.
longshore currents
The water table ______ in humid regions.
roughly parallels the land surface
Because sand grains are heavier than clay and silt particles, sand grains move close to the ground in a leaping pattern called ______.
saltation
Discharge is the product of average stream width times average stream depth times ___.
stream velocity
____ coasts are common because sea level has been rising for the past 15,000 years.
submerging
A stream can lengthen its valley by headward erosion.
true
Permeability is
Ability of rock or soil to allow water to flow through it
Why is Antarctica considered a desert?
Because it receives very little precipitation
______ streams receive water from the saturated zone.
Gaining or effluent
What happened to sea level during the ice ages of the Pleistocene?
Sea level went down more than 10 meters.
What is the reason that coasts such as those in Canada, north Britain, and Scandinavia have been uplifted?
The crust has uplifted due to plate tectonics.
How is a pothole formed?
Through the swirling, scouring action of pebbles on a hard stream bed
A(n) _____ is a coastal inlet that is formed by a drowned glacial carved valley.
fiord
A glacial valley drowned by rising sea level is
fjord
The high runoff following sporadic desert downpours can create sudden local floods called ______.
flash floods
The broad strip of land built up by sedimentation on either side of a stream channel is
flood plain
___ beds form the main body of a delta with angles of inclination up to 20 to 35 degrees in small sandy deltas.
foreset
_______ are sometimes built perpendicular to shore in an attempt to protect beaches that are losing sand from longshore drift.
groins
Which of the following water reservoirs in the hydrologic cycle contains the least amount of fresh water?
the atmosphere
The energy that moves sand along a beach ultimately comes from ____.
the wind
The unsaturated zone is __.
the zone above the water table
A glacier will flow faster where it is steeper and _____.
thicker
Because of their low rainfall, intermittent stream flow, and dry stream beds, deserts lack ____.
through flowing streams
A _____ is a bar of sediment that connects a former island to the mainland.
tombolo
Movement of cobbles and boulders by rolling, sliding, or dragging in a streambed is called ____ load.
traction
A U-shaped valley (in cross section) is characteristic of glacial erosion.
true
A baymouth bar is a ridge of sediment that cuts a bay off from the open ocean.
true
A desert is any region which has a dry or arid climate with a low rainfall of less than 25 cm per year.
true
A fiord is a glacially-cut valley flooded by rising sea level.
true
A large trunk glacier erodes downward more rapidly and carves a deeper valley than do smaller tributary glaciers.
true
A particle of water in a wave moves in a circular orbit as the wave passes; the particle returns to its original position after the wave has passed.
true
A pediment is an erosional surface underlain by solid rock, while a bajada is depositional and is underlain by sediment.
true
A trellis stream pattern consists of parallel main streams with short tributaries meeting them at right angles.
true
An alluvial fan is a fan- or cone-shaped pile of sediment that forms where a stream emerges from a narrow mountain canyon.
true
An esker is a long sinuous ridge of ice.
true
Artesian wells are associated with confined aquifers.
true
Compared to the flow of water in streams, most ground water moves relatively slowly.
true
Deposits of calcite built up in caves by dripping water are called dripstone or speleothems.
true
During the most recent ice age, sea level was at least 100 meters lower than at present.
true
Glaciers with a positive budget are advancing glaciers.
true
Gravel beaches are found on coasts with low wave energy.
true
Gravel beaches have a steeper face slope than sand beaches.
true
Gravel has both high porosity and excellent permeability.
true
Groundwater is a major economic resource.
true