Test 4 Geology
T or F. Gradients usually increase downstream in a major river system
f
T or F. The beach side of the barrier islands is identical to the lagoon side in terms of overall appearance, sediments, and vegetation
f
What does the following figure best illustrate
karst topography
Flash floods
local rainstorms, sometimes after a forest fire, deluging streams, creating a wall of water that roars down a canyon, and taking everything in its path; Big Thompson Canyon flood in Colorado, 1976
It is thought that convection within the ______ of the rotating planet generates Earth's magnetic field
outer core
What term describes the situation when an aquitard lies above the main water table and cause a localized saturated zone? ****
perched water table
Which one of the following does or did NOT contribute to Earth's internal heat?
plate tectonics, a process that describes the movements of lithospheric plates on Earth
Discharge is ****
the volume of water flowing past a single point in a given unit of time
Western United States (North America)
warm and weak, tectonically active; slow S waves
Indicate the most likely location for each of the following by selecting the correct response from the map.
A: Oxbow lake B: erosion at a cutbank C:a deposition at a point bar D:meander moving toward this label E:meander moving away from this label F:migration of the stream creates a floodplain
Identify the indicated karst features at each label on the diagram.
A: Sinking Stream B: Water Table C:Sinkholes D:Solution Valley E:Aerated Cave F:Water-filled cave
Match each part of the hydrologic cycle with its proper description.
A: The locally saturated atmosphere releases some of its water onto both land and oceans B:Some rainfall and snow melt seep through undersaturated soils to become groundwater. C:Some rainfall and snow melt quickly rush over the surface, forming streams. D:As water on the surface is heated, it becomes vapor and escapes into the atmosphere.
Indicate the formation process associated at each label on the photograph.
A: Water drips through small openings, leaving calcite behind B:Water splashes onto the cavern floor and leaves calcite precipitate begin C: The water table has fallen below this level
Identify the indicated layers of Earth's interior based on their physical properties by selecting the correct response.
A: solid iron and nickel composition B: liquid iron and nickel composition C: rich in mineral perovskite D: composed of the ultramafic rock peridotite E: Composition comparable to granodiorite F: predominantly basalt
Which processes describes how a stream cuts a channel into bedrock by constantly hitting the bedrock with the sediment it carries?
Abrasion
Tidal flats are mostly submerged during ebb tides (T/F)
False
A_______ tide is a tidal current flowing through an inlet into a bay or estuary
Flood
______Currents move offshore sand and water parallel to the beach
Longshore
Which of the following terms does not belong with the other terms? a. Spit b. Tombolo c. Barrier island d. Marine terrace
Marine terrace
The ___________ is the seismic discontinuity that forms the boundary between the crust and mantle. ***
Moho
The seismic boundary between the crust and the mantle is referred to as the __________. ***
Moho
Where is stream erosion concentrated along a meandering stream?
On the outer bank of a meander bend
For a passing wave, the depth below which the motion of water particles become negligible is equal to....
One-half the wavelength
The __________ of the Earth does not transmit S wave ****
Outer Core
A _______ is an abandoned, cutoff, meander loop.
Oxbow Lake
What is the Vadose zone? ****
The unsaturated zone above the water table where both air and water occupy pore space
Excessive groundwater withdrawals can lead to which of the following results?
The water table drops or declines in elevation
Continental crust is generally thicker than oceanic crust
True
Differences in the height of Earth's geoid is measured relative to a perfect ellipsoid.
True
In areas underlain by unconsolidated or weakly consolidated strata, lowering of the water table can cause the land to subside
True
Neap tides are produced when the Moon is at right angles to the line connecting the Earth and Sun (T/F)
True
The geothermal gradient is a curve showing the increase of temperature with depth within Earth's interior.
True
The lowest base level for most streams is sea level
True
Water infiltrates down to the water table from influent streams
True
The example of seismic tomography illustrated below shows hotter and colder regions of Earth's mantle based on measured variations in __________
Velocities of S Waves
Describe a confined aquifer.
Water flows into the aquifer on one end and is trapped by aquitards above and below
An artesian well is one in which ________.
Water rises above the top of the aquifer without any pumping
Water movement and sand transport parallel to the beach are fundamentally caused by...
Waves impinging obliquely onto a beach
Which of the following statements concerning artesian wells is not true?
When the well penetrates the aquifer, the groundwater reverses flow such that the water table drops in the well
Which of the following statements best describes how geysers erupt? *****
With a slight reduction in pressure, water in a saturated, natural conduit suddenly boils, sending a plum of steam and hot water into the air above the vent
Which is Earth's weakest layer?
asthenosphere
Where do rocks that are 180 million years old or younger, are very dense, and consist of gabbro and basalt form?
at mid-oceanic ridges
Where are most caverns created
at or just below the water table
Which of the following did not contribute to Earth's internal heat? *** A. Heat released by colliding particles during the formation of Earth 4.5 billion years ago B. Solar radiation from the early sun C. Heat released as iron crystallized to form the solid inner core of early Earth D. Heat emitted by radioactive decay of isotopes of uranium, thorium, and potassium
b
Which of the following is not part of the hydrologic cycle? a) water moving into creeks and streams following a rainstorm b) calcium carbonate dissolving in soil water and groundwater c) water evaporating from a lake d) water infiltrating into the soil and bedrock
b
Of the materials listed below (with their relative levels of rigidity), which one will transmit seismic waves most rapidly? ***
basalt (most rigid)
What force pushes groundwater from pore to pore below the water table? ***** A) integrated saturation impulse B) permeability steepness C) pressure gradient or hydraulic gradient D) seepage affluence actor
c
Describe the Farallon plate under North America
cold, dense, ancient Pacific seafloor
Failure of human structures function; Johnstown Flood in Pennsylvania in 1889
dam-failure floods
The source of heat that produces deep mantle plumes is believed to be located at the __________. ****
"D" Layer
A stream begins at an elevation of 200 meters and flows a distance of 400 kilometers to the ocean? What is the average gradient?
.5 m/km
Approximately how deep within the Earth is the "D" layer? ****
2900 Kilometers
Which level indicates the zone where no direct P-waves are received?
A
what is the difference between a bar and a point bar?
A bar is a small-scale channel deposit, sometimes elongated, in the middle of a braided stream; a point bar is a deposit of sediment on the inside of a meander.
Which one of the following coastlines would typically have wave-cut cliffs, sea stacks, sea arches and sea caves? ****
A coastline where bedrock is vigorously eroded as sea level rises
A perched water table develops when......
A horizontal aquitard above the regional water table prevents downward-percolating water from reaching the main aquifer. Downward percolating water accumulates above the aquitard to form a secondary zone of saturation above the main water table.
Which of the following statements logically explains why parts of some cavern systems are aerated?
A nearby, downcutting stream lowered the water table after the caves had formed
yazoo tributary
A river that parallels the main river but is separated from it by the natural levee; it often can flow through a backswamp before entering the main stem
An aquifer is ...
A saturated, porous, and permeable layer or stratum
Which best describes the difference between a delta and an alluvial fan?
A stream deposits sediment at its mouth in water in a delta; a stream deposits sediments along steep mountain slopes in an alluvial fan
Distributary
A stream that flows away from the main stem as the water flows across an alluvial fan, delta, or deep-sea fan; it does not rejoin the main branch
Which of the following statements correctly describes how stream terraces can form?
A temporary base level is eliminated; the stream cuts down upstream from the old temporary base level, and the former floodplain is left well above the present elevation of the stream
Which one of the following best characterizes the asthenosphere?
A zone of softened peridotite in the upper mantle
Which of the following accounts for the largest usage of groundwater in the United States? ******
Agriculture (public supply) and Irrigation
What type of terrain is characteristic of the drainage pattern shown?
Alternating weak and resistant bedrock characteristic of folded terrain
Discovered the discontinuity between the crust and the mantle in 1909
Andrija Mohorovicic (Moho) ***
Which of the following statements concerning unconfined aquifers in coastal areas is correct
Any salty water in the aquifer will rise if the water table is lowered by pumping
What are permeable layers of rock, such as layers of sand or gravel that freely transmit groundwater, called?
Aquifers
layer of rock or sediment that hinders groundwater flow
Aquitard (opposite of Aquifer)
How does wave refraction affect the crest and trough orientations of incoming waves along a beach?
As the waves move into shallower water, the angle between crests and shoreline decreases and become more parallel
Which level indicates the P-wave shadow zone?
B
Which one of the following statements correctly describes how stream terraces can form?
Base level drops, the stream actively downcuts, and the former floodplain is left well above the present elevation of the stream
****who calculated depth of core boundary at 2900 Kilometers
Beno Gutenberg
How does a water gap form? ***
Both antecendent and superposed streams can create water gaps
Which level indicates the zone where direct P-waves are received?
C
Inge Lehmann ***
Discovered boundary between solid inner core and liquid outer core in 1936
The common, rock-forming mineral_______, which comprises the rock_________, most readily dissolves in slightly-acidic groundwater?
Calcite / Limestone
Which of the following describes the total sediment load transported by a stream? ***
Capcity
Contamination of wells by saltwater intrusion is commonly a problem in _____________
Coastal Areas
Which of the following describes the changes likely to occur in an unconfined aquifer around a pumping well? ******
Cone of Depression forms around the well
Heat from the core is transferred through the mantle to the base of the crust mainly by __________***
Convection
_________ is the transfer of heat by the displacement of cooler materials by hot materials ****
Convection
In areas where an aquifer occurs in unconsolidated sediments, excessive pumping can cause the land to subside as the sediments compact. Which list below identifies areas of subsidence caused by water withdrawal?*******
Correct Mexico City, San Joaquin Valley in California, New Orleans, and Texas
What mathematical relationship relates groundwater velocity, gradient, viscosity of the fluid, and permeability of the aquifer? ****
Darcy's Law
A dam and reservoir are constructed on a graded river. What will happen?
Deposition upstream from the dam; channel downcutting below
Which of the following factors do not influence stream turbulence and average velocity?
Dissolved load and water temperature above freezing
At the head of a delta, the major channel splits into smaller channels that follow different paths to the sea. These smaller channels are known as_______ ***
Distributaries
What is the relationship between drawdown and the cone of depression associated with a pumping well?
Drawdown is the distance between the original water table and the water level in the well
What three factors cause Earth's magnetic field?
Earth's rotation and spiral flow in the iron-rich fluid of the outer core
Which one of the following feature is not characteristic of a submergent coastline?
Elevated, wave-cut terraces
As P waves pass from the mantle into the outer core, velocities increase abruptly
False
Earth's radius is slightly longer at the pole, but shorter at the equator
False
What is an intermittent hot spring that ejects a fountain of hot water and steam with great force called?
Geyser
Which one of the following is NOT a speleothem?
Geyserite
After ice sheets and glaciers, which of the following reservoirs contains the next highest percentage of the Earth's freshwater?
Groundwater
Steepest channel slope (gradient) with highest channel roughness, low discharge, and low flow velocity
Headwater
Mouth
Highest discharge, lowest channel slope, smoothest channel, and highest flow velocity
pore space
Holes in rocks and sediments similar to those in a sponge
For unconfined aquifers, what hydrologic factor is approximated by the slope of the water table? ***
Hydraulic Gradient
How does urbanization (paving, etc.) affect runoff and infiltration in a small, previously forested, drainage basin? ***
Infiltration decreases while runoff increases
What is a braided channel? ***
It is a wide and shallow stream usually at the ends of glaciers; it is choked with sediment, where there is not much of a slope
_________ are coastal structures designed to keep tidal and harbor inlets from shifting location or filling with sand.
Jetties
Swash and backwash describe....
Movements of water and sand as waves wash up and back again on a beach
Which of the following features characterize wide streams and valleys?
Natural levees and broad floodplains
Which of the following statements about the 'D' layer is false?
Occurs directly below continental and oceanic crust
_____________ is probably closest in chemical composition to the upper mantle.***
Peridotite
Ability of rock or soil to allow water to flow through it
Permeability
What type of stream pattern develops only on growing mountains like volcanoes or where the land surface is tectonically doming upward?
Radial
Which of the following features are characteristic of downcutting streams and a youthful stage of valley evolution?
Rapids, V-shaped valley, and lots of whitewater
The P-wave shadow zone is largely the result of...
Refraction of P waves crossing the mantle-core boundary
Channel roughness, discharge, channel size, and flow velocity are balanced in the center of the diagram and chart
Region of meanders
___________________ is seasonal precipitation or spring snowmelt over many watersheds and drainage basins; Mississippi River system annually
Regional floods
Who discovered central core of Earth in 1906 using the shadow zones of P and S waves***
Richard Dixon Oldham
How are Spits and baymouth bars formed?
Sand is deposited partly or completely across an inlet or bay by beach drift and longshore currents
A_______ is an isolated, exposed remnant of bedrock that is now offshore
Sea Stack
Which of the following must result in a lower base level for rivers and streams?
Sea level falls; land rises
_________________ are built behind a beach and serve to protect from strong waves and surges
Seawalls
Which of the following make up the suspended loads of most rivers and streams?
Silt and clay-sized, detrital grains
Which of the following rock types would have the largest capacity to naturally remove sewage pollutants? *****
Slightly clayey sand
______ are the maximum-amplitude tides produced when the Sun, Earth, and Moon are aligned.
Spring Tides
A_____________ is the icicle-like speleothem that grows down from the roof of a cavern
Stalactite
A______ refers to the broad dome of water moving with the eye and frontal portion of a hurricane
Storm surge
Many large rivers in the Colorado Plateau meander in deep, narrow canyons and have no floodplains. How could this happen?
Streams flowing in meanders cut down as the plateau rose
Large estuaries are more common on a(n) ___________ coastline.
Submergent
Why has Niagara Falls lasted so long and cut its channel in the cliff backwards 7 miles (11 kilometers)?
The Lockport Dolostone is a resistant rock unit that covers a wide zone between Lake Erie and Lake Ontario, and the Niagara River has to erode the weak layers underneath before it can retreat upstream.
What is the circulation of Earth's water supply between the hydrosphere, atmosphere, geosphere, and biosphere called? ***
The hydrologic cycle
Which of the following statements is INCORRECT with regard to the water table?
The level of the water table never changes regardless of the time of year
Which of the following best describes the development of distributaries at the mouths of major rivers such as the Mississippi River?
The main channel divides into several smaller channels, carrying water in varying paths to base level.
porosity
The percentage of the total volume of a rock or sediment that consists of open spaces.
Which of the following is a characteristic of P waves?
They pass through all of the layers of the Earth, refracting when they leave one state of matter and enter a different state of matter
A natural sand bar or low, sand ridge that connects one island to another island or to the mainland is called a ___________?
Tombolo
The Earth's magnetic field originates by...
Weak electrical currents associated with fluid motions in the outer core
In what section of the United States are the majority of host springs and geysers located?
Western United States
Which of the following characteristics are found in all good aquifers? *** A) High porosity and high permeability B) Low permeability and high potability C) High potability and high portability D) Low porosity and low permeability
a
Which of the following is good evidence for a solidified, inner core? *** A. P waves are faster in the inner core than in the outer core B. S waves do not pass directly through the core C. S waves are slower in the inner core than in the outer core D. S waves are focused at the center of the P-wave shadow zone
a
The water table is..... ******
a boundary between saturated rock below and unsaturated rock above
How is the rotational speed of the inner core speculated to compare with that of the rest of the planet
a century of more faster
Tributary
a small stream that flows into a larger stream or river
Which of the following best describes a water gap?
a steep-walled notch cut through a tectonic structure, usually a ridge of tilted rock
The two transition zones in Earth's mantle, one at 400 km and the other at 670 km depths, are characterized by
abrupt increases in P- and S-wave velocities due to closer atomic packing of crystal structures in mantle minerals
What will happen when a dam and reservoir are constructed on a graded river?
deposition upstream from the dam; channel downstream of the dam
Ice-jam floods
form blockages in the channel; occur repeatedly in the Red River of the North
The greatest change in the velocity of P waves occurs at the __________ boundary.
mantle-outer core
Western Africa and the Pacific Ocean
megaplumes of warm material ascending towards the surface
Eastern North America and Africa (part of the ancient continent, Pangaea)
old portion of continent; fast S waves
Continents emit more heat than old oceanic seafloor because continents contain higher amounts of heat-producing _______
radioactive isotopes
A seismic wave may change direction, without bouncing back, when crossing the boundary between two different Earth materials. This phenomenon is called ________.
refraction
T or F. Natural levees are formed where the coarsest sediments are deposited adjacent to the channel during floods
t
Which river has the largest discharge of any in the world? ***
the Amazon
