GEO CHP 17, Geo 101 CH 18, Ch 19 Test*************

A glacier will always _______ from its source area if the rate of accumulation is greater than the rate of ablation. A. Advance B. Retreat

A. Advance

Scratches or troughs carved into rock by the sediment embedded in ice at the base of a flowing ice sheet are called ____________. A. Glacial striations B. Arêtes C. Horns D. U-shaped valleys

A. Glacial striations

Cirques and horns are features associated with _______________. A. Mountain glaciation B. Continental glaciation C. Glacial outwash deposits D. Loess deposits

A. Mountain glaciation

What is the most recent ice age? A. Pleistocene ice age B. Permian ice age C. Late Protozoic ice age D. Early Protozoic ice age

A. Pleistocene ice age

Desertification can accelerate due to

A. overpopulation B. careless agriculture C. excessive groundwater pumping D. all of the above **

The geometry of sand dunes is strongly influenced by ________

A. the strength of the wind B. the consistency of wind direction C. the abundance of sand D. all of the above **

The surface of the sea never freezes. A. True B. False

B. False

Today, continental glaciers are limited to Antarctica and ________________. A. Alaska B. Greenland C. Canada D. Siberia

B. Greenland

Wind blows finer particles long distances from glacial environments, where they settle out to form ______________. A. Firn B. Loess C. Outwash D. Till

B. Loess

The periodic changes in Earth's orbital eccentricity, Earth's axial tilt and direction (precession) that cause ice ages was first proposed by ___________. A. Richter B. Milankovitch C. Mohorovicic D. Agassiz

B. Milankovitch

Uplifted areas are subjected to weathering and erosion at the surface; this provides an example of ____________. A. unidirectional change B. cyclical change C. neutral feedback

B. cyclical change

At the present, glaciers cover about ______ of the surface of the continents. A. 1% B. 5% C. 10% D. 20%

C. 10%

Sediments deposited directly by glaciers as they melt are characterized by _______________. A. Uniformly coarse grain size B.Uniformly fine grain size C. An absence of sorting D. Graded bedding

C. An absence of sorting

An important long-term factor determining whether glacial ice will form on continents has likely been the proportion of which gas in the atmosphere? A. Oxygen B. Nitrogen C. Carbon Dioxide D. Carbon Monoxide

C. Carbon Dioxide

A crater discovered in the Yucatan peninsula in Mexico appears to be the right age to be a result of an impact which brought about the extinction of numerous species at the end of the ____________ period. A. Silurian B. Jurassic C. Cretaceous D. Tertiary

C. Cretaceous

An increase through time in the proportion of heavy oxygen (18O) in a sequence of carbonate sediments implies ____________. A. the sediments are young enough to have been exposed to radiation from underground nuclear testing B. the organisms that secreted the carbonate favored 18O over the far more abundant 16O C. Earth was becoming warmer over time D. Earth was becoming cooler over time

C. Earth was becoming warmer over time

With the increased amount of information that has been discovered in recent years, scientists have become increasingly certain that ____________. A. Earth's climate is not warming to any significant degree B. Earth's climate is warming due to variation in solar output; human inputs of atmospheric greenhouse gases have not had a significant influence C. Earth's climate is warming, and human inputs of atmospheric greenhouse gases are most likely responsible

C. Earth's climate is warming, and human inputs of atmospheric greenhouse gases are most likely responsible

When sea level rises, causing the ocean to fill a glacially carved valley, a _______ results. A. Smorgasbord B. Tarn C. Fjord D. Ford

C. Fjord

Stratified, sorted sand and gravel are deposited by _________________. A. Mountain glaciers B. Continental glaciers C. Glacial outwash streams D. Wind

C. Glacial outwash streams

An angular peak surrounded by three or more bowl-shaped depressions formed by a mountain glacier is termed a(n) ___________________. A. Arête B. Cirque C. Horn D. Tarn

C. Horn

Cobbled and boulders that have been dropped by a glacier are termed ______. A. Erratics B. Loess C. Moraines D. Varves

C. Moraines

A hanging valley is formed when a ____________________. A. Smaller glacially carved valley intersects a larger glacially carved valley B. Smaller stream-cut valley intersects a larger stream-cut valley C. Smaller stream-cut valley intersects a larger glacially carved valley D. Stream-cut valley is on the upthrust side of a normal fault

C. Smaller stream-cut valley intersects a larger glacially carved valley

The hole in the ozone layer has been brought about by anthropogenic emissions of ____________. A. carbon dioxide B. methane C. chlorofluorocarbons (CFCs) D. polychlorinated biphenyls (PCBs)

C. chlorofluorocarbons (CFCs)

Which of the following types of global change is not part of a cycle of change, and thus irreversible? A. orogenic uplift B. melting and crystallization of sedimentary rock to form igneous rock C. evolution of life on Earth D. flooding of the continents due to global warming

C. evolution of life on Earth

Currently, global warming appears to be most strongly affecting the climate and wildlife of ____________ regions. A. equatorial B. temperate C. polar D. deep sea

C. polar

The presence of liquid water on Earth's surface is ____________. A. unremarkable; many other bodies in the solar system have liquid water B. unique within the solar system, but is an inherent feature of Earth that would be found regardless of the Earth-Sun distance C. unique within the solar system; liquid water would not have developed had Earth been much closer to or farther from the Sun

C. unique within the solar system; liquid water would not have developed had Earth been much closer to or farther from the Sun

Which of the following processes may be responsible for short-term cooling, yet in the long term favors warm, greenhouse climate? A. atmospheric carbon dioxide B. formation of extensive ice sheets C. volcanism D. formation of large continents located near the poles

C. volcanism

Which of the following processes releases carbon dioxide to the atmosphere? A. photosynthesis B. weathering of silicate rocks C. volcanism D. deep burial of peat to produce coal

C. volcanism

How does carbon cycle through the various Earth systems?

Carbon dioxide in the atmosphere dissolves in the ocean to form carbonate (and bicarbonate) ions. These ions are removed by a variety of organisms to produce calcite and aragonite skeletons, which collect as fragments and grains at the bottom after the organisms die, eventually forming limestone. Carbon dioxide can also be removed, either directly from the atmosphere or from solution in the ocean, through biogenic photosynthesis, to produce organic carbon. Organic carbon may become incorporated into the rock record in shale, oil, and coal, but some may be released to the environment through animal respiration and flatulence. Weathering of silicate rocks removes atmospheric carbon dioxide, producing bicarbonate ions. Burning fossil fuels releases atmospheric carbon dioxide, as do volcanic eruptions.

Describe how carbon dioxide-induced global warming takes place, and how humans may be responsible. What effects might global warming have on the Earth System?

Carbon dioxide is called a greenhouse gas because, much like the glass of a greenhouse, it allows solar radiation to reach the Earth, but traps the infrared radiation that the Earth emits to outer space. Because of its relative abundance, carbon dioxide is the most significant of the greenhouse gases in the atmosphere. Humans are likely responsible for increased atmospheric carbon dioxide (and resultant greenhouse warming); human burning of fossil fuels emits carbon dioxide to the atmosphere, and the increase in atmospheric carbon dioxide over the past two centuries is too rapid to have been caused by geologic processes. Effects of global warming on the Earth System include sea-level rise, the breakup of polar ice shelves, the melting of glaciers, a reduction in sea ice formation, shifts in patterns of precipitation and climate belts, changes in the range distributions of animals, imperilment of polar wildlife, stronger storms (including hurricanes), and disruption of oceanic currents (which may bring further climatic change, including the cooling of high latitudes).

About ______ of an iceberg lies below the surface of the sea. A. 20% B. 40% C. 60% D. 80%

D. 80%

T/F? Nearly all biological and chemical systems on Earth are disconnected and are best studied in mutual isolation.

False

T/F? Pollen has changed over time through evolution, but the pollen of individual species cannot be used to interpret ancient environments because most species inhabit all environments.

False

What is the ozone hole, and how does it affect us?

The ozone hole is a large opening in the stratospheric ozone layer over Antarctica (a smaller hole sits atop the Arctic) caused by the reaction of ozone with anthropogenic chlorofluorocarbons.

How do paleoclimatologists study ancient climate change?

The record of sedimentary rocks can be used to decipher ancient climate change, because certain rocks are characteristic products of specific environments; further, fossils provide environmental clues because many organisms have narrow environmental tolerances. Oxygen isotope ratios in ice and carbonate sediments provide a proxy for average temperatures. Ancient air bubbles may reveal atmospheric carbon dioxide levels (and thus the effectiveness of Earth's greenhouse). Variations in growth rings and recorded human history can be used to infer climate change in the very recent past.

T/F? The factors that affect Earth's long-term climate are different from those that affect climate on shorter time scales.

True

What are some of the likely scenarios for the long-term future of the Earth?

Unless destroyed by impact, Earth will be consumed by the red giant stage of our Sun's evolution, approximately 5 billion years from now.

What factors explain short-term climate change?

a. The abundance of sunspots (cool spots on the surface of the Sun, which may represent magnetic storms) varies over the course of a decade or so, and may affect total incident solar radiation. Recently, some researchers have suggested changes in the rate of influx of cosmic rays may also have an effect. b. Earth's orbital shape, magnitude of tilt, and direction of tilt vary over Milankovitch cycles with periods in the tens of thousands of years. These parameters influence whether glaciers are likely to descend over the continents or melt. c. Earth's albedo can be increased by an increase in aerosols (such as volcanic ash), cloud cover, surface ice, or the spread of deserts and grasslands over land that was once forested. d. Ocean currents may change course, altering the hydrologic system that brings warmth to some areas and cold, dry conditions to others. e. Abrupt changes in concentrations of greenhouse gases can also cause short-term climate change.

What are the possible causes of long-term climate change?

a. The sizes and positions of the continents are important. For large continental glaciers to grow, it is favorable to have large continents in regions near the poles; small continents bathed in tropical oceans favor greenhouse conditions. b. Volcanoes emit carbon dioxide, which adds to the greenhouse effect. c. Uplifted areas are sites of intense weathering, and chemical weathering draws down atmospheric carbon dioxide. d. Limestone, coal, organic-rich shale, and oil contain carbon, so when produced in vast quantities and buried, they keep carbon from reaching the atmosphere as carbon dioxide. Carbon burial is a check on the greenhouse effect. e. The appearance or extinction of certain life forms may also impact climate by either adding carbon dioxide to the atmosphere or removing it.

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

To qualify as a desert, a region must be

arid, with less than 15% of the ground surface vegetated

_______are flat-topped hills that can be found in Monument Valley, Arizona.

buttes

Deserts in coastal regions are most likely to be found where the currents are

cold

Most regions that are now deserts have

experienced other climates in the geologic past

The definition of a desert depends on a region's temperature.

false

Saltation of sand involves

grains bouncing 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

The Sahara of Africa is a desert primarily because it is located

in the subtropics

most expansive hot deserts on Earth occur

in the subtropics, between 20° and 30° north or south of the equator

As compared to humid climates, rates of chemical weathering in deserts are

much slower

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 dry wash (an arroyo) is a steep-sided valley produced by

scouring erosion by water and sediment during flash floods

In most deserts, the scarcity of rainfall means that most of the physical weathering and erosion is accomplished by the wind.

true

A rock abraded by windborne particles on multiple faces, forming a sharp edge in between, is termed a________

ventifact

The deserts found in the western United States form primarily due to being located

within the rain shadow of one or more mountain ranges

Give some examples of events that cause catastrophic change.

Comet or asteroid impact, mass extinctions, explosive or hyperactive volcanism, and sudden episodes of global warming or cooling can alter climate rapidly with disastrous results.

T/F? Due to global warming, the Earth is now warmer than it ever has been in geologic history.

False

A newspaper editorial columnist this week writes a scathing attack on the scientific consensus concerning global warming. His position is that global warming is not occurring, and his supporting evidence is the fact that Sheboygan, Wisconsin, had a record low temperature (in 150 years of record keeping) on February 6 last winter. Which statement(s) about the editorial is/are correct? A. Assuming the columnist is correct in reporting the record low temperature, then indeed he is correct in his assertion that global warming is not occurring. B. The columnist is confusing weather (day to day and seasonal variation in temperature, humidity, precipitation, and air pressure) with climate (variability in these factors over time scales of decades or longer). C. The columnist does not understand that scientists do not expect global warming to produce a gradual uniform increase in temperature for every locality on every day of the year. Geologically rapid warming is expected to increase air and sea temperature averaged across the planet throughout the year (measured over time spans of decades to centuries), but it will also bring shifts in weather patterns that could locally cause extreme heat or cold, drought, or intense flooding. D. Both B and C are correct.

D. Both B and C are correct.

Cape Cod, Massachusetts, and Long Island, New York, are both examples of Pleistocene glacial ___________ that have been further built up by wave-deposited sands. A. Drumlins B. Kettles C. Eskers D. End moraines

D. End moraines

When continental ice sheets melt away, the surface of the underlying continent gradually rises back up. This process is called ________________. A. Ice loading B. Glaciation C. Interglaciation D. Glacial rebound

D. Glacial rebound

Which of the following is NOT true? A. Ice is naturally occurring B. Ice is an inorganic solid C. Ice has a definite chemical composition (H2O) D. Ice has an irregular crystal structure

D. Ice has an irregular crystal structure

Sediments deposited directly by glacier as they melt are termed ____________. A. Firn B. Loess C. Outwash D. Till

D. Till

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 glacier in the valley will possess _______________. A. Four lateral moraines and no medial moraines B. Three lateral moraines and no medial moraines C. Two lateral moraines and two medial moraines D. Two lateral moraines and one medial moraine

D. Two lateral moraines and one medial moraine

Which of the following is an important long-term (acting over spans of tens of millions of years) factor in global climate change. A. decrease in albedo due to aerosols from volcanic eruptions B. variation in Milankovitch orbital parameters C. variation in the abundance of sunspots D. atmospheric concentration of carbon dioxide

D. atmospheric concentration of carbon dioxide

Which of the following processes removes carbon dioxide from the atmosphere? A. exhalation by animals B. burning of coal and other fossil fuels C. volcanism D. photosynthesis

D. photosynthesis

During most of the Mesozoic, Earth was ____________. A. about as warm as today B. covered in extensive continental glaciers C. about as warm as the Holocene climatic optimum D. significantly warmer than at any time within the last few million years

D. significantly warmer than at any time within the last few million years

The highest recorded temperature in the United States was in

Death Valley

Give some examples of how humans have changed the Earth.

Extraction of rock and groundwater, overhunting and overfishing, destruction of forests and grasslands, and pollution of the air, streams, and oceans have led to subsidence, an increase in mass wasting, famine, high rates of biotic extinction, acid rain, smog, a hole in the ozone layer, and so on.

T/F? All changes within the Earth system are unidirectional and cannot be reversed.

False

T/F? Cyclical global change includes the formation of core, mantle, and crust from a homogeneous mixture, a state to which one day Earth will return.

False

What processes control the rise and fall of sea level on Earth?

Global sea level is primarily controlled by the volume of glacial ice on continents, which has a negative effect, and the volume of mid-ocean ridge volcanoes, which has a positive effect. At times of rapidly moving plates (abundant mid-ocean-ridge volcanism), an increase in excess carbon dioxide leads to a stronger greenhouse effect, warming the ocean and melting glaciers (if any are present), which raises sea level by adding ocean water. Rapid volcanism also produces thick mid-ocean-ridge volcanic chains, which displace water onto the continents. Conversely, when sea-floor spreading rates are low, ridge volume is small and the atmospheric level of carbon dioxide is also low. The resultant reduction in the greenhouse effect favors the formation of continental glaciers, freezing out water that is now unavailable to the ocean.

Contrast icehouse and greenhouse conditions.

Greenhouse climate is warmer than that of today's (especially at the poles), and is characterized by high atmospheric concentration of carbon dioxide and relatively high sea level, with no continental glaciers at the poles. In contrast, icehouse conditions are colder, with permanent ice present at the poles and relatively low levels of atmospheric carbon dioxide and low sea level.