geology 2 exam 2
Valleys carved by glaciers tend to be shaped like the letter _____, whereas valleys carved by water tend to shaped like the letter _____.
U, V
A hanging valley is formed when a ____________.
a. smaller glacially carved valley intersects a larger glacially carved valley
Mars has polar ice caps that differ from the Earth's Antarctic ice cap in that ____________.
a. the Martian caps consist of a combination of water ice and frozen carbon dioxide (dry ice)
A glacier will always advance from its source area if the rate of accumulation is greater than the rate of:
ablation
_____ make up a majority of the ocean floor worldwide
abyssal plains
a(n) _____ is a wedge of sand and gravel deposited by the distributary channels that arise when an ephemeral stream reaches a plain at the base of a slope
alluvial fan
Sediments deposited directly by glaciers as they melt are characterized by
an absence of sorting
To qualify as a desert, a region must be _____.
arid, with less than 15% of the ground surface vegetated
Major oceanic surface currents travel
at an angle to prevailing winds as a result of the Coriolis effect
The form and topography (depth profile) of the ocean floor is termed
b. bathymetry
Tidal reach is affected by ___________?
b. the position of the Sun
Estuaries most commonly have salinity that is ____________.
brackish (between freshwater and marine salinity)
Glacial ice exhibits ________ behavior near the top but ________ behavior beneath a depth of 60 m.
brittle and ductile
Which trench includes the world's deepest sea floor (more than 11 km below sea level)?
c. Marianas Trench
As compared to freshwater, saline ocean water is ____________ and therefore provides ____________ support to floating objects.; a.; less dense; more buoyant; b.; less dense; less buoyant; c.; denser; more buoyant; d.; denser; less buoyant
c. denser; more buoyant
Flooded valleys that were excavated by glaciers are termed ___________? a.; deltas; b.; tombolos; c.; fjords; d.; fords
c. fjords
An important long-term factor determining whether glacial ice will form on the continents has likely been the proportion of which gas in the atmosphere?
carbon dioxide
A bowl-shaped depression that formed by a mountain glacier is termed a(n) ____.
cirque
Deserts in coastal regions are most likely to be found where the currents are
cold
Most hot deserts ________.
cool off greatly at night because of sparse vegetation, dry air, and little cloud cover
at 30 degrees north latitude, at the north edge of tropical (hadley) cell convection in the northern hemisphere
cool, dry air sinks, becoming drier as it heats up
Most of the igneous rocks within oceanic abyssal plains are ____________.
covered by clay and the skeletal remains of microplankton
Areas on the southern margins of the continental glaciers of the northern hemisphere were much ____________ during Plio-Pleistocene glaciations than they are today, as suggested by evidence of large ____________ during this time.
d. wetter; pluvial lakes
As waves approach shore in shallow water their speed:
decreases
the density of seawater increases with
decreasing temperature and increasing salinity
a bathymetric map of the ocean would utilize contours to connect points of equal
depth of the sea floor below sea level
Rip currents flow ____?
directly away from the shoreline
If currents are largely directed toward shore, the area is likely to experience
downwelling
Cape Cod, Massachusetts, and Long Island, New York, are both examples of Pleistocene glacial ____________ that have been further built up by wave-deposited sands.
end moraines
When sea level rises, the ocean may invade a river valley, producing a nearshore body of water of mixed and variable salinity termed a(n) _____.
estuary
as compared to continental interiors, surface temperatures in costal regions
experience a less extreme range throughout the year
the strongest winds within a hurricane are found in the _______?
eye wall
advance and retreat of massive glacial ice sheets during glacial episodes is a simple function of incident sunlight. glacial behavior can be modeled precisely by considering only milankovitch orbital variation and variable solar output. T or F
false
walking across an antarctic ice sheet during winter would not be very treacherous, because icy surfaces are not slippery if the temperature is well below freezing. T or F
false
Wind blows finer particles long distances from glacial environments, where they settle out to form
firn
an intermediate product in the transformation of snow to glacial ice is
firn
When sea level rises, causing the ocean to fill a glacially carved valley, a _____ results.
fjord
wave refraction causes longshore currents to travel ____?
from headlands toward embayments
Tidal reach will be greatest locally during a ___________?
full or new moon
Stratified sorted sand and gravel are deposited by _______.
glacial outwash streams
Saltation of sand involves _____.
grains hopping into the air, traveling for a short distance, and returning to the ground
During heavy rainstorms, rates of physical weathering and erosion are
greater in deserts than in humid climates, where vegetation tends to hold soil together
Because of wave refraction, erosion along an irregular coastline is ________.
greatest in headlands (points of land projected out toward the sea)
An angular peak surrounded by three or more bowl-shaped depressions formed by a mountain glacier is termed a (an) ____________.
horn
the deepest segments of the ocean floor are found
in trenches associated with subduction zones
sand groins _____?
increase erosion rates in the region down current from the groin
the periodic changes in earth's orbital eccentricity and magnitude, as well as in the direction (precession) of Earth's axial tilt, affect the advance and retreat of ice sheets was first proposed by ____
milankovitch
Cirques and horns are features associated with _____.
mountain glaciation
As compared to humid climates, rates of chemical weathering in deserts are
much slower
At the equatorial ocean basins, sea surface temperatures may reach 30deg.C or greater; at the sea floor 5 km below, the temperature is ___________?
near freezing (2 degrees- 4 degrees celsius)
the gobi of mongolia is a desert primarily because it is located
near the center of a large continent
The Atacama of Chile is a desert primarily because it is located
next to a cold ocean current
Desert climate associated with a rain shadow is found
on the leeward (inward) side of coastal mountain ranges
A wave will disturb the water to a depth equal to ____________.
one-half of its wavelength
longshore currents flow ______?
parallel to the shoreline
which type of continental coastline features a much broader continental shelf
passive continental margins
Ice is a substance with a high albedo, which means it _____.
reflects most of the light that falls upon it
Wave crests ___________?
refract (bend) so as to impact the shore in a nearly parallel manner
Due to the Coriolis effect, surface currents in the oceans are always pulled to the ________ in the northern hemisphere as compared to the prevailing wind direction
right
native americans produced petroglyphs by etching into
rocks that had been coated with desert varnish
An arroyo is a steep-sided, linear trough produced by ________.
scouring erosion by water and sediment during flash floods
The magnitude of tidal effect (lateral extent of the intertidal zone between low and high tides) is affected by the ____________.
slope of the coastline and the position of the surf
The Sahara of Africa is a desert primarily because it is located
subtropics
global circulation of ocean water is influenced by
surface winds, coastal upwelling and downwelling, sinking of cold and saline water
A lake that forms within a bowl-shaped depression formed by a mountain glacier is termed a(n)_____.
tarn
The iron oxides and manganese oxides that produce desert varnish on the exterior surfaces of rocks are derived from ions ____________.
that occur naturally on the surfaces of carbonate and silicate rocks
The geometry of sand dunes is strongly influenced by
-Strength of Wind -Consistency of Wind Direction -Abundance of sand
at the present, glaciers cover about ______ of the surface of the continents
10%
the current interglacial interval began a little more than ______ years ago
10,000
a coastline is more likely to consist of a tidal flat than a beach if _____
the shore is protected from strong waves
the highest recorded temperature on earth was in a
57.8 degrees celsius at El Azizia, Libya
a bajada is
An apron of sediment along a mountain front created by the coalescence of alluvial fans.
A remnant ridge separating two bowl-shaped depressions formed by a mountain glacier is termed a (an) ____________.
Arete
what percentage of seawater, on average, consists of dissolved salt ions?
B. 3.5%
Because glacial advance is driven by gravity, it is impossible for glaciers to advance over perfectly flat terrain. a. true b. false
B. False
Every shoreline experiences a tidal reach (difference in elevation between high and low tide) of about 3 m.; a.; true; b.; false
B. False
Most regions that are now deserts have ____________. A. been deserts throughout the geologic past B. experienced other climates in the geologic past
B. experienced other climates in the geologic past
The most expansive hot deserts on Earth occur in the ________.
B. in the subtropics, between 20° and 30° north or south of the equator
Compared to continental lithosphere, oceanic lithosphere is ____________.
B. thinner
approximately what percentage of earth's surface is covered with water?
C. 70%
The shallowest portion of ocean found along the margins of continents in regions termed ____________.
C. continental shelves
Playas are places where you would expect to find abundant ____________ exposed at the surface.
C. evaporites (salts)
of the choices below, which portions of the sea floor are most steeply tilted?
D. continental slopes
Desert varnish is a coating on aerially exposed desert rocks that is primarily composed of ____________.
D. iron and maganese-oxides
Today, continental glaciers are limited to Antarctica and ________.
Greenland
the first scientist to theorize the past presence of glaciers in europe was
Louis Agassiz
the most prominent force inducing tides on earth is the
Moon's gravitational pull
Given the modern continental configuration, it is much easier for large continental ice sheets to become established in the ____________ Hemisphere than in the ____________ Hemisphere.
Northern and Southern
Sediments deposited directly by glaciers as they melt are termed _____.
till
Rogue waves arise from constructive interference of multiple convergent waves; these waves occasionally can be more than 100 feet high.; a.; true; b.; false
true
in most deserts, the scarcity of rainfall means that most of the physical weathering and erosion is accomplished by the wind. T or F
true
Two mountain glaciers merge their flows in a glacial valley. Prior to their merger, each possessed two lateral moraines and no medial moraines. As a result of a merger, the new larger glacier in the valley will possess
two lateral moraines and one medial moraine
A rock that has been abraded by windborne particles on multiple faces, forming a sharp edge in between, is termed a ____________.
ventifact
Some of the physiographic features that cause extreme aridity may be found together within a single desert, but the deserts found in the western United States form primarily due to being located ____________.
within the rain shadow of one or more mountain ranges
