Q&A Hero

Q: Permanent streams in desert regions are rare, and when they do occur, ________. A) they originate in a glacier region B) they have numerous tributaries to keep them supplied with water as they cross the desert C) they originate outside of the desert region and have few tributaries in the desert D) they get their water from wadis and arroyos

Q: Desert and steppe lands cover about what percentage of Earth's land area? A) 10% B) 66% C) 30% D) 3%

Q: Desert streams are characterized by ________. A) increasing discharge downstream B) decreasing discharge downstream C) short, frequent tributaries D) long, frequent tributaries E) well-sorted, rounded clasts of sediment

Q: If all of the ice now stored in Antarctica's glaciers melted, what would happen? A) Sea water would become fresh enough to drink because glaciers are made of fresh water. B) Sea level would rise flooding many coastal cities. C) Because glacial melt water is less dense than sea water, the glacial melt will float on top of the ocean and not affect the land areas. D) Ice bergs would float to the equatorial regions of the earth where they would lower the temperature and cause the climate to become cooler.

Q: Milankovitch cycles are used to explain the cycles of cold and warm climates that characterized the Ice Ages based on ________. A) plate tectonics and sea level rise B) solar flares and variations in the moon's orbit over time C) evolution of plants and animals and human impact D) variations in the earth's orbit about the sun and precession of the earth's axis

Q: What of the following is considered to be the most likely cause of the Quaternary Ice ages? A) human activity releasing "greenhouse" gases B) plate tectonics moving continents to polar regions C) variations in the earth's orbit D) variations in the Sun's intensity

Q: Our detailed knowledge of the glacial cycles and their duration is based primarily on ________. A) ice cores B) seafloor sediments C) land sediments D) climate records

Q: Ice Age glaciers had many indirect effects. Which one of the following was not such an effect? A) formation of mountains B) extinction of some organisms C) changes in some river courses D) sea level fluctuations

Q: Which of the following did not exist prior to the Quaternary Ice ages? A) the Mississippi River B) the Colorado River C) Antarctica D) the Great Lakes E) the arctic ocean

Q: Glacial sediments or tills are characterized by ________. A) striations B) cirques, artes, and hanging valleys C) moraines and glacial flour D) wide variations in sizes of clasts E) very fine-grained, highly polished clasts

Q: A ________ forms when a block of ice is buried in drift and subsequently melts, creating a pit. A) tarn B) paternoster C) kame D) kettle

Q: A(n) ________ represents a former meltwater channel or tunnel in glacial ice that was filled with sand and gravel. A) esker B) yazoo ridge C) valley plain D) kettle

Q: The term drift ________. A) refers only to alpine glaciers B) refers only to moraines C) is synonymous with the term till D) means any sediments of glacial origin

Q: Which of the following is not a major factor controlling glacial erosion? A) ice thickness B) rate of glacial ice movement C) strength of the glacial ice near its base D) character of the surface beneath the glacier

Q: A(n) ________ is likely to host a waterfall or steep rapids today. A) outwash plain B) hanging valley C) striated drumlin D) horn peak

Q: ________ are erosional features produced by valley/alpine glaciers. A) Moraines B) Cirques C) Eskers D) Drumlins

Q: Abrasion and plucking generally involve what part of a glacier? A) the internal flowage zone B) the snout zone C) the surface brittle zone D) the bottom or base

Q: How do glaciers acquire their load of sediment? A) Sediments are deposited on glaciers by streams that flow into the glaciers. B) Sediments are plowed up into the glacier by the front terminus of the glacier as it moves downhill. C) Sediments are plucked off the rocks at the base and sides of the glacier. D) Sediments fall off the cliffs surrounding the glacier and move through crevasses to the base of the glacier. E) All of the answers describe major contributors to the glacial sediment load.

Q: If the glacial budget is balanced (accumulation equals wastage), then ________. A) the terminus of the glacier is stationary B) the ice front will retreat C) the glacier will not flow downhill D) the ice front will advance

Q: Most of an iceberg is under water because ________. A) ice is more dense than seawater B) seawater is more dense than ice C) the mass of an iceberg is concentrated in the zone of wastage D) the mass of an iceberg is concentrated in the zone of accumulation

Q: What condition is most necessary to build a glacier? A) The elevation of the area must be high enough to allow snow to fall regularly. B) The temperature must be cold enough to cause snow to fall regularly. C) The snow must be able to move downhill slowly. D) More snow must fall in the winter than melts in the summer.

Q: If you fall into a crevasse, what is the maximum depth you are likely to fall? A) 10 meters B) 25 meters C) 50 meters D) 100 meters

Q: At the base of a glacier, the ice moves by ________. A) fracturing B) fracturing and sliding C) sliding and ductile flow D) ductile flow and fracturing

Q: Crevasses (deep fractures or cracks) form because ________. A) not all of the ice in a glacier moves downhill at the same rate in the glacier B) as the glacier moves over irregular topography the bottom of the glacier (known as the zone of fracture) cracks and the cracks propagate upward to the surface of the glacier C) as the glacier moves over irregular topography, the brittle upper layer or zone of fracture is subject to tension and cracks above the ductile layer D) as the glacier moves over irregular topography, cracks can form anywhere in the glacier but they are called "crevasses" only if they are near the surface E) there is not always the same amount of ice available in all areas so cracks form when the ice tries to move and fill in empty parts of the glacier

Q: Which one of the following applies to a valley glacier that lengthens (extends the position of its terminus downslope) over a period of many years? A) wastage exceeds accumulation B) accumulation exceeds wastage C) accumulation and wastage are about equal D) none of the above

Q: Today, glaciers cover approximately ________ percent of the earth's surface. A) 1 B) 10 C) 30 D) 50

Q: Ice sheets can be ________. A) several centimeters thick B) several meters thick C) several kilometers thick D) tens of kilometers thick

Q: How is sea ice different from glacial ice? A) Sea ice is thicker than glacial ice, and sea ice floats while glacial ice does not float. B) Sea ice is thicker than glacial ice, and both sea ice and glacial ice can float. C) Sea ice is thinner than glacial ice, and both sea ice and glacial ice can float. D) Sea ice is thinner than glacial ice, and sea ice floats while glacial ice does not float.

Q: Which one of the following is not true of glaciers? A) originate on land B) exist only in the Northern Hemisphere C) show evidence of past or present flow D) form from the recrystallization of snow

Q: Glacial ice sheets are the largest glaciers and they currently cover ________. A) Antarctica, Greenland, Alaska, the Andes Mountains, the Arctic Sea, and the Alps B) The Arctic Sea, the Alps, Greenland, Antarctica, and Alaska C) Alaska, Antarctica, and Greenland D) Greenland and Antarctica E) only Antarctica

Q: In the figure above, identify the letter corresponding to a playa lake.

Q: In the figure above, identify the letter corresponding to an alluvial fan.

Q: In the figure above, identify the letter corresponding to a playa or salt flat.

Q: In the figure above, identify the letter corresponding to a Bajada.

Q: Briefly explain how Plate Tectonic Theory can explain evidence that some tropical regions have experienced glaciation in the past but cannot explain the Quaternary Ice Ages.

Q: The major rivers in the U.S., including the Colorado and Rio Grande, originate in mountainous regions with significant contributions from snow melt and then cross arid regions before supplying the water needs for several cities in the U.S. and Mexico. Discuss the potential impact of climate change on the water supplies.

Q: Wind is included along with gravity, water, and ice as an agent of erosion. In many national parks and other areas of natural beauty, statements are often made that credit wind as having sculpted the landscape. Briefly discuss the importance of wind as an agent of erosion and explain why such statements are probably geologically inaccurate.

Q: In recent years there has been more discussion of droughts in places like eastern Texas, which is not considered a desert, than in southern Arizona which clearly is a desert. Does this mean that arid environments are changing and it would be better to invest in farm land near Phoenix, Arizona, than near Austin, Texas, for long term financial security?

Q: Would most features of alpine glaciation be preserved in the geologic record? Why or why not? What about continental glaciation?

Q: On the blanks provided, fill in the name of the labeled features that formed as a product of alpine glaciation.

Q: Antarctica's ice represents approximately 65% of the earth's fresh water supply and many populated regions need that water. Should we develop a program to mine Antarctica's ice and redistribute it to areas where it is needed? Explain your answer.

Q: Explain why crevasses only penetrate partway through a glacier. What limits their depth?

Q: What distinguishes Valley or Alpine Glaciers, Ice Sheets, Ice Shelves, and Sea Ice from each other?

Q: Which letter, S thru Z, corresponds to the object in the photo labeled "E"?

Q: Which letter, S thru Z, corresponds to the object in the photo labeled "D"?

Q: Which letter, S thru Z, corresponds to the object in the photo labeled "C"?

Q: Which letter, S thru Z, corresponds to the object in the photo labeled "B"?

Q: Which letter, T thru Z, corresponds to the object in the photo labeled "A"?

Q: Deposits of windblown silt are called ________.

Q: The low, bedrock ridges and peaks of a highly eroded, basin and range, desert landscape are called ________.

Q: What is the name for the very large pluvial lake that once existed in northwestern Utah?

Q: What term denotes a glacial valley that was partly flooded as sea level rose?

Q: A(n) ________ is a closed depression formed by melting of an ice block buried in a moraine or outwash plain.

Q: Bowl-shaped depressions in bedrock at upstream ends of alpine glacial valleys are called ________.

Q: What term describes open fissures in the brittle surface ice of a glacier?

Q: The steeper, leeward slope of a sand dune is called the slip face.

Q: Windblown loess, like sand, typically accumulates as mound-like dunes.

Q: Blowouts are broad, shallow depressions excavated by deflation.

Q: A playa is an intermittent lake on the floor of a desert valley.

Q: Bajadas develop from coalescence of alluvial fans along fronts of mountain ranges in arid lands.

Q: The Basin and Range region of the western United States is an excellent example of a mountainous desert landscape.

Q: Deserts are hot, lifeless sand-covered landscapes shaped largely by the forces of wind.

Q: The Colorado River is an example of a large wash.

Q: Arid and semiarid climates cover nearly one-third of Earth's land surface.

Q: Running water is an important erosional agent in many arid lands despite infrequent rainfalls.

Q: Glaciation has only been recorded for the Quaternary period of the earth's history demonstrating that the cause of the Ice Ages is the earth's orbit moving farther from the Sun.

Q: During the Ice Age, the climate was occasionally warmer than it is today.

Q: Moraines are the only glacial deposits composed of till.

Q: Stratified drift is sorted by glacial ice as the glacier begins to melt and drop its load of sediment.

Q: Till is an unsorted sediment deposited directly from the melting glacial ice; stream action is not involved.

Q: Artes, horns, and U-shaped valleys are erosional features carved from bedrock by glaciers.

Q: A cirque represents an erosional feature formed in what was an important accumulation zone for snow and ice at the upstream head of a glacier.

Q: Fiords are glacier-cut valleys that flooded as sea level rose in post-glacial times.

Q: Glaciers will not form near the equator because the Sun is too strong in that area.

Q: Melting and calving are two forms of ablation.

Q: When a glacier is retreating, the upstream ice is still moving forward toward the downstream terminus of the glacier.

Q: The North Pole is covered by glaciers.

Q: Examine the words and/or phrases for each question below and determine the relationship among the majority of words/phrases. Choose the option which does not fit the pattern. sand dune deflation blowout desert pavement

Q: What is the name of the localized lowering of the water table shown in the diagram below?

Q: When examining the geology of a region for potential aquifers, what characteristics or factors would you consider? Also, what areas (based on natural and human factors) would you avoid?