How Much of Earths Land Surface is Currently Covered by Glacial Ice

Answer Key 1) B 2) D 3) D 4) B 5) C 6) D 7) A 8) C 9) C 10) D 11) D 12) A 13) A 14) A 15) D 16) B 17) D 18) C 19) D 20) A 21) C 22) C 23) A 24) C 25) B 26) D 27) B 28) D 29) B 30) A 31) A 32) A 33) C 34) C 35) B 36) A 37) A 38) B 39) C 40) A 41) A 42) C 43) C 44) D 45) D 46) D 47) C 48) A 49) C 50) C Answer Key 51) C 52) D 53) A 54) C 55) A 56) C 57) B 58) D 59) A 60) C 61) B 62) C 63) C 64) B 65) C 66) A 67) B 68) D 69) C 70) D 71) B 72) A 73) D 74) B 75) A 76) D 77) A 78) B 79) D 80) D 81) A 82) B 83) D 84) B 85) D 86) B 87) C 88) C 89) D 90) C 91) D 92) FALSE 93) FALSE 94) TRUE 95) TRUE 96) TRUE 97) FALSE 98) TRUE 99) FALSE 100) FALSE Answer Key 101) 102) 103) 104) 105) 106) 107) 108) 109) 110) 111) 112) 113) 114) 115) 116) 117) 118) 119) 120) 121) 122) 123) 124) 125) 126) 127) FALSE TRUE TRUE TRUE TRUE FALSE FALSE FALSE TRUE TRUE TRUE TRUE TRUE FALSE TRUE TRUE FALSE FALSE FALSE TRUE FALSE FALSE TRUE TRUE FALSE TRUE TRUE MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) How much of Earths land surface is currently covered by glacial ice? A) 25% B) 10% C) 45% 1) D) <1% 2) During ice - age times when glaciers are present, water is typically stored as glacial ice and removed from the hydrologic cycle for ________. A) less than a few months B) up to several years C) 100s of millions of years D) 10s of thousands of years 2) 3) The main direct geologic effect(s) of glaciers is(are) to ________. A) warm the global climate by absorbing more solar radiation B) raise global sea level by depressing the crust C) reduce high latitude marine sedimentation by reducing biologic productivity D) erode the continental landscape and to transport and deposit sediments 3) 4) Where is the world's second largest continental ice sheet? A) Siberian Russia B) Greenland C) Antarctica D) Iceland 4) 5) Where is the world's largest ice sheet located today? A) Greenland B) Siberian Russia D) Iceland 5) C) Antarctica 6) Which one of the following statements concerning glaciers is not true? A) Long, extended, alpine glaciers occupied valleys in most high elevation and high latitude, mountainous areas in the United States, Canada, and Europe at one or more times during the past two million years. B) Piedmont glaciers form on lowlands at the base of mountainous terrain. C) Ice sheets are larger than ice caps. D) The volume of water tied up in the Antarctic ice sheet is about the same as the total discharge of the Amazon River in one year. 7) Compared to earlier or subsequent streams in the same valleys, alpine glaciers move carry ________ sediment. A) very much slower; vastly more B) a little slower; only finer C) mainly in the winter; mostly very coarse D) faster; less 6) but 7) 8) Ice masses that entirely covers uplands and plateaus such as the islands in Nunavut or Vantnajukull in Iceland are called ________. A) crevasse splays B) alpine glaciers C) ice caps D) ice sheets 8) 9) At what depth or thickness of ice does glacial ice make the transition from brittle fracture to plastic flow? A) 1 metre B) 10 metres C) 50 metres D) 5 metres 9) 1 10) Glaciers can deform internally to behave like a plastic material and flow because ________. A) There are layers of pure liquid water between the annual layers of ice. B) There are layers of air between the layers of ice. C) There are round rock particles within the ice that act like little ball bearings. D) The bonds between successive layers of ice are weaker than those within a single layer, allowing the glacier to slip like a stack of cards. 10) 11) Where would you likely find glaciers that could only move by plastic flow above the bed? A) near the terminus of any ice sheet B) on ice shelves C) in high elevation tropical settings D) in polar regions or with extreme cold where ice is frozen to the bedrock 11) 12) 12) is one of the three ways a glacier can move over its bed. A) Basal slip B) Morainal sliding C) Crevassal slip D) Frost heaving 13) What physical property of H 2O allows glaciers to flow, particularly by basal slip? A) pressure melting B) dipole forces C) high viscosity D) spontaneous recrystallization to the cubic structure 13) 14) The bottom or downward tip of a crevasse marks the . A) top of the internal deformation and flowage zone, and the base of the brittle zone of fracture B) boundary between the basal sliding and external flowage zones C) boundary between parts of the glacier moving by basal sliding and crevassal slip D) bottom of the basal sliding zone 14) 15) When glaciers suddenly speed up and move at up to 100 times their normal rate, this is called a ________. A) splurge B) luge C) galumph D) surge 15) 16) When glaciers suddenly move forward they are said to A) lunge B) surge 16) ________. C) purge D) calve 17) Where is the equilibrium line on a glacier? A) at about 150 m depth B) below the zone of wastage C) beneath the terminal moraine D) where the zone accumulation meets the zone of wastage 18) Which process occurs where a glacier enters the sea? A) kaming B) salinization 17) 18) C) calving 19) Approximately how much of an iceberg protrudes above waterline? A) 0.1% B) 90% C) 3% 2 D) surging 19) D) 10% 20) How do most icebergs in the North Atlantic Ocean originate? A) by calving of large tidewater glaciers on Greenland B) as calved blocks of glacial ice that float northward from Antarctica C) as masses of sea ice that float southward from the Arctic Ocean through Davis Strait D) as ice shelves that float northward from Antarctica 20) 21) Which one of the following applies to a valley glacier that lengthens (extends its terminus downslope) over a span of many years? A) accumulation and wastage are about equal; the older ice moves farther B) wastage exceeds accumulation C) accumulation exceeds wastage D) the glacier experiences no accumulation or wastage 21) 22) What does it mean when the terminus of a glacier has been stationary for several years? A) The glacier is storing up energy preparing to surge forward. B) Global warming has ceased. C) The local glacial budget is in equilibrium. D) The glacier is still frozen but has quit moving. 22) 23) Which phrase best describes what would likely happen during the retreat of a valley glacier? A) A line of stakes across the glacier would continue to move down valley as the terminus of the glacier slowly retreated. B) A line of stakes would retreat slowly up valley as the ice withdraws to its source region. C) A line of stakes across the glacier would be gradually lowered to the valley floor directly beneath where they were originally placed. D) Who cares? The beer would get too warm! 23) 24) 24) is the best explanation for a glacial surge. A) The climate cools suddenly and a retreating glacier begins to advance B) Intense chemical weathering of clays beneath the ice causing it to slip C) Melting at the base of the glacier resulting in increased rates of basal slip D) Heavy snowfalls resulting in avalanches loading the glacier in the zone of accumulation 25) As a glacier advances over a fractured bedrock surface, it loosens, lifts, and incorporates blocks of rock in a process called ________. A) striation B) plucking C) frost wedging D) hydraulic lifting 25) 26) Abrasion and plucking generally involve what part of a glacier? A) the snout zone B) the surface, brittle zone C) the internal, flowage zone D) the basal, sliding zone 26) 27) A cross - valley profile is typical of canyons and valleys eroded and deepened by alpine or valley glaciers. A) V B) U C) S D) Y 27) 28) A 28) is an erosional feature specifically produced by alpine glaciation. A) kame B) V - shaped valley C) lateral moraine D) U- shaped valley 3 29) The steep, triangular shaped cliffs that flank hanging valleys are called ________. A) lateral moraines B) truncated spurs C) faceted nunataks D) arêtes 29) 30) Which of the following glacial features would typically be found in close proximity? A) hanging valley and truncated spur B) drumlin and fjord C) cirque and terminal moraine D) outwash plain and horn 30) 31) A(n) ________ is likely to host a large stream with a waterfall or steep rapids today. A) hanging valley B) striated drumlin C) horn D) truncated spur 31) 32) A cirque is made of ________. A) rock C) sand and gravel 32) B) mud D) till 33) The focal point of a valley glacier's growth is a bowl shaped depression called a A) downer B) kettle lake C) cirque 34) are erosional features produced by valley/alpine glaciers. A) Eskers B) Drumlins C) Cirques ________. D) nest 33) 34) D) Moraines 35) Which of the following is often associated with a cirque basin in high, mountainous terrain? A) kettle B) tarn lake C) arête pond D) saline lake 35) 36) Headward erosion by alpine glaciers on two sides of a mountain ridge can remove enough rock to intersect forming a pass called a ________. A) col B) tarn C) monument D) cirque 36) 37) A fjord is . A) a stream valley deepened by glacial erosion, that floods as sea level rises B) a glacier - cut valley that is dammed by an end moraine and a large lake is formed C) a large, kettle - pocked moraine left as an island when sea level rises following melting of the ice D) a glacier - cut valley which sinks below sea level due to glacial rebound after the ice melts 37) 38) A ________ is a glacier - cut valley that was partly flooded as sea level rose. A) tarn B) fjord C) arête 38) 39) A horn is made of A) sand and gravel C) rock D) kettle lake . 39) B) till D) mud 40) An ice carved, asymmetrical bedrock knob with the steep side downhill is called a A) roche moutonnée B) nunatak C) drumlin D) kame 4 . 40) 41) Which of the following best describes the term glacial drift? A) the sedimentary materials outwash and till B) floating of icebergs southward from the north polar seas C) the slow, southward advance of the continental ice sheets over Canada and North America during the Pleistocene D) slow, plastic flow the brittle zone of a glacier 41) 42) An erratic is made of A) till C) rock 42) . B) sand and gravel D) mud 43) Boulders that are lithologically different than the local bedrock (like a loose Precambrian gneiss found sitting on top of bedded Paleozoic limestones) are called ________. A) come from aways B) transportees C) erratics D) ectatics 43) 44) Which one of the following statements concerning glacial deposits is not true? A) Till is deposited directly from the ice; outwash is deposited by meltwater streams. B) Outwash is mainly stratified sand and gravel. C) Tills are poorly sorted and their fragments are mostly angular. D) Glacial erratics are blocks of rock that are too large for the glacier to move. 44) 45) The big quartzite rock sitting on the prairie at Okotoks, Alberta, and similar, smaller blocks strung out over 600 km from their eroded bedrock source near Mt. Edith Cavell in Jasper National Park, make up ________. A) a lateral moraine B) Alberta's most profound political contribution C) a glacial lineation D) an erratics train 45) 46) A moraine is primarily made of . A) rock B) outwash 46) C) mud D) till 47) What type of moraine is formed by the merging of two lateral moraines at a junction of two valley glaciers? A) ground B) recessional C) medial D) collateral 47) 48) Diamond - bearing kimberlites occur in the Northwest Territories, Saskatchewan and Ontario. What type of glacial deposit would be most useful for tracing kimberlite cobbles and minerals directly to their bedrock source area? A) end or ground moraine formed by a continental ice sheet B) kames C) lateral or medial moraines formed by alpine valley glaciers D) kame terraces 48) 5 49) The oldest extensive glacial deposits preserved in: Finland, North America, South Africa, and Western Australia occurred ________ years ago, which ________ took for evidence of his ________ hypothesis. A) 11,000; Lancelot du Lac; Big Tilt B) 2.3 million; Mikhail Budyko; Big Chill C) 2.3 billion; Paul Hoffman; Snowball Earth D) 250 million; Alfred Wegener; Continental Drift 49) 50) ________ is a gently rolling sheet of till with an irregular surface deposited under the weight of a glacier. A) Kame sheet B) Outwash blanket C) Ground moraine D) Terminal moraine 50) 51) What glacial landform is responsible for a large portion of the water resources for greater metropolitan Toronto? A) the drumlin field near Guelph and Peterborough B) the remnants of glacial Lake Bonneville C) the Oak Ridges moraine and its included channel fills of coarse glacial outwash D) pingoes and blocks of buried ice mined from glacial sediments between Toronto and Muskoka 51) 52) A(n) ________ is a depositional feature composed primarily of till and usually associated with continental glaciation, not with alpine glaciers. A) moraine B) cirque C) outwash deposit D) drumlin 52) 53) Which one of the following is not normally a feature of glaciated, alpine terrains? A) drumlin B) lateral moraine C) horn 53) 54) A drumlin is usually made of ________. A) sand and gravel C) till D) arête 54) B) mud D) rock 55) Drumlin fields contain ________. A) smooth, tapering, asymmetric ridges of till usually formed and shaped beneath a continental ice sheet B) mounds of outwash deposited by meltwater streams at the snout of a glacier C) bowl - shaped depressions eroded largely by frost action and glacial plucking D) smooth, striated, bedrock ridges shaped and polished by a glacier's erosive action 55) 56) All of the following descriptions apply to stratified drift (not till) except for ________ . A) deposited or redeposited by glacial meltwater B) commonly layered, well sorted sand and gravel beds C) rock flour deposited directly from advancing ice D) deposited in advance of the ice front on outwash plains, in glacial lakes, or fjords 56) 57) A(n) A) fjord 57) would likely be situated next to a large end moraine. B) outwash plain C) pluvial lake 6 D) cirque 58) ________ are both deposited by meltwater streams. A) Terminal moraines and cirques C) Valley moraines and ice sheet trains 58) B) Recessional kettles and erratics D) Outwash plains and valley trains 59) A(n) ________ is similar in appearance to a sinkhole of a karst area. A) kettle B) moraine C) esker 60) A A) tarn 59) D) cirque forms when stagnant, glacial ice melts after being buried by till or outwash. B) horn C) kettle D) drumlin 61) An ice contact deposit is classified by its A) internal stratification C) grain size . 60) 61) B) shape D) age 62) Which glacial landform was originally deposited as a fan against glacial ice or within depressions on the ice surface? A) ground moraines B) end moraines C) kames D) valley trains 62) 63) All of the following landforms and geologic features are direct products of glacial erosion except for ________. A) truncated spur B) striated bedrock C) kame terraces D) horn 63) 64) Kame terraces were originally deposited ________. A) as a broad band behind the advancing ice front of a continental ice sheet B) along the sides of a glacial valley C) in meltwater channels perpendicular to a melting continental ice front D) under water along a floating ice shelf 64) 65) An esker is made of A) till C) sand and gravel 65) . B) mud D) rock 66) A(n) represents a former meltwater channel or tunnel on, in, or beneath glacial ice, that became filled with sand and gravel. A) esker B) drumlin C) valley train D) kettle 66) 67) Who was the first scientist to hypothesize and promote the idea of a great Pleistocene Ice Age with extensive and far reaching effects? A) Paul Hoffman B) Louis Agassiz C) Milutin Milankovitch D) Alley Oop 67) 68) Upon what evidence did Agassiz base his ice age theory? A) stacks of glacial drift with intervening "warm period" soil horizons B) astronomical calculations for cyclic variations in Earth's orbit C) spectroscopic measurements for variations in the solar output D) glacial landscapes in the Swiss Alps extended far beyond existing ice fronts 68) 7 69) The ________ was the most recent Pleistocene glacial episode in North America. A) Indianan B) Kansan C) Wisconsinan D) Dakotan 69) 70) The is not the name of a Pleistocene glacial episode in North America. A) Illinoian B) Nebraskan C) Kansan D) Dakotan 70) 71) Which of the following is the correct listing of the classical North American glacial stages from oldest to youngest? A) Nebraskan, Indianan, Illinoian, Wisconsinan B) Nebraskan, Kansan, Illinoian, Wisconsinan C) Indianan, Kansan, Nebraskan, Ohioan D) Kansan, Illinoian, Iowan, Dakotan 71) 72) When did Earth's climate deteriorate enough to start this current cycle of glaciations in Antarctica? A) > 20 million years ago B) about 2.4 million years ago C) 10,000 years ago D) 17,000 years ago 72) 73) During the maximum extent of the last Ice Age, which region remained free of ice cover? A) northern Siberia B) southern Ontario C) Greenland and Iceland D) central Yukon an portions of central and western Alaska 73) 74) Independent of any local scale erosion or deposition, thick accumulations of ice load the crust and upper mantle ________. A) causing the crust to thrust and fold like in a mountain building event B) causing the crust to subside C) causing the crust to rise up with an immediate elastic rebound D) causing the crust to drift laterally, instigating major tectonic motions 74) 75) During the peak of the last Ice Age circa 17 Ka ago, the total volume of glacial ice was about ________ km 3 , or about ________ times its present amount. 75) A) 70 million; 2.8 C) 2.42 X 1012 ; a million B) 7 thousand; 55 D) 25 million; 100 76) What was the maximum lowering of sea level during the last Ice Age? A) - 20 m B) -85 m C) - 38 m 76) D) - 100 m 77) What was the most far reaching effect of the Ice Age on the world's oceans? A) Global sea levels dropped about 100 metres. B) The seas got about - 7 ° C cooler on average over the whole planet. C) The seas got much less saline because of all the melting icebergs. D) It was too cold for phytoplankton to live in the seas. 77) 78) Which was not true during the height of last Ice Age? A) One could have walked from SE Asia to Indonesia. - Atlantic Ocean. B) The continent of Atlantis was above sea level in the mid C) One could have walked from France to Britain. D) One could have walked or paddled a small boat from Siberia to Alaska. 78) 8 79) During the peak of the last Ice Age, continental land area was larger and you could have walked across the English Channel because ________. A) the continents expanded as they got colder B) the polar ice caps flattened Earth so much that the continents were higher C) sea floor spreading hadn't separated England from France yet D) there was so much ice that the global sea level was about 100 m lower than now 79) 80) Which one of the following prominent features were significantly larger than at present day during the Pleistocene glacial episodes? A) terminal moraines of continental ice sheets that moved south from Canada B) subaerial fan deltas covering more extensive coastal plains C) horns, arêtes, and cirques produced by alpine glaciation D) the Great Lakes and Lake Agassiz 80) 81) Approximately how long ago did the last of the great North American ice sheets melt? A) 15,000 yrs B) 1500 yrs C) 1.5 million yrs D) 150,000 yrs 81) 82) How long ago was the glacial maximum of the last Ice Age? A) 6000 years B) 17,000 years C) 11,000 years 82) D) 2000 years 83) During the retreat of the last ice sheets, how long ago did modern sea level become established? A) 17,000 years B) 11,000 years C) 20,000 years D) 6000 years 83) 84) Prior to its sudden emptying down the St. Lawrence around 11,000 years ago, largest lake in North America. A) Maligne Lake B) Lake Agassiz C) Great Bear Lake D) Lake Bonneville 84) was the 85) When did the great southern hemisphere glaciation of Pangaea occur? A) Pleistocene Epoch B) Pliocene Epoch C) Proterozoic Eon D) Permian Period 85) 86) The great glaciation that affected the Southern Hemisphere supercontinent Pangaea (parts of Africa, South America, India, Australia, and Antarctica) occurred ________. A) 56- 45 m.y. ago in early Cenozoic time B) 300- 200 m.y. ago in late Paleozoic time C) 800- 700 m.y. ago in late Proterozoic time D) 3800- 3600 m.y. ago in early Archean time 86) 87) developed and promoted the first comprehensive mathematical model that periodic variations in the geometry of Earth's orbit (eccentricity, obliquity, precession) were responsible for climatic oscillations of 1000 to 100,000 years. A) I. Venetz B) P. Hoffman C) M. Milankovitch D) L. Agassiz 87) 88) All of the following are thought to possibly contribute to ice ages except for ________. A) eccentricity B) plate tectonics C) comets D) precession 88) 9 89) Which one of the following could not have significantly affected climatic variations, and advances and retreats of ice sheets, during the Pleistocene Epoch? A) periodic wobbling of Earth's rotational axis B) cyclic precession of Earth's orbit C) episodic variations in the Sun's energy output D) gradual movements of Earth's tectonic plates 89) 90) The of the geologic time scale represents the time of Earth's most recent "Ice Age." A) Proterozoic Eon B) Permian Period C) Pleistocene Epoch D) Pliocene Epoch 90) not glacial drift? 91) Which of the following sediment types is A) laminated glacial lake muds with striated and polished dropstones B) ground moraines of till C) stratified outwash fans D) Pleistocene deep sea oozes 91) TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false. 92) Glaciers move so quickly that, on an annual basis, they are not very effective at removing any significant amount of water from the hydrologic cycle. 92) 93) The only true modern day, continental ice sheets are on Antarctica and in the Canadian Arctic 93) 94) Alpine glaciers form in pre - existing stream valleys at high altitudes. 94) 95) Except for vestigial ice fields, Alpine glaciers are usually many times longer than they are wide. 95) 96) Because ice floats on seawater, coastal outlet and piedmont glaciers seldom erode much below the elevation of sea level at the times the glaciers are active. 96) 97) The volume of the Antarctic ice sheet is about equal to the total volume of ice in all alpine glaciers of the world. 97) 98) To make glacial ice, requires a thickness of about 50 metres for pressures to be great enough. 98) 99) Crevasses are short, narrow cracks in the plastic flow zone of a glacier that alternately open and close as the ice flows along. 99) 100) Melting and evaporation are two forms of ablative calving. 100) 101) The downstream end or snout of a glacier advances over intervals of time during which ablation exceeds accumulation. 101) 102) The down - valley end of the glacier is it's terminus. 102) 103) Even when a glacier is retreating, the up down-valley terminus of the glacier. -valley ice is still moving forward toward the 10 103) 104) Surges in glacial movement are probably related to unusually fast rates of basal slip. 104) 105) Rock flour consists of silt - sized, rock and mineral particles produced by glacial abrasion. 105) 106) The ruggedness of the terrain in high elevation mountainous areas was caused by continental glaciation. 106) 107) The most spectacular glacial landforms are caused by vast continental ice sheets. 107) 108) Tributary glaciers follow the rule of streams and downcut to the level of the main trunk glacier to smoothly join in at the same elevation. 108) 109) A cirque represents an erosional feature formed in what was an accumulation area for snow and ice at the up- valley head of a glacier. 109) 110) Fjords are glacier - cut valleys that flooded as sea level rose in post 110) - glacial times. 111) Arêtes, horns, and U - shaped valleys are erosional features carved from bedrock by valley glaciers. 111) 112) Mt. Logan and Mt. Assiniboine are both horns which are erosional remnants carved from more extensive mountainous areas by glaciers. 112) 113) Unlike moving water or wind, flowing glacial ice cannot sort the particle sizes that it carries, so its deposits are very poorly sorted. 113) 114) All unconsolidated glacial sediments irrespective of grain size, sorting, or depositional process are referred to as till. 114) 115) Because ice carries both large and small particles, and cannot sort sediments, we recognize that is a poorly sorted sediment deposited directly from the melting glacial ice; stream action is minimal. till 115) 116) End or recessional moraines form when the rate of ablation equals the rate of ice advance. 116) 117) The recessional moraine is the largest and outermost of many terminal moraines formed by a retreating glacier. 117) 118) Drumlins are believed to represent deltas built into lakes by meltwater streams. 118) 119) Sand and gravel deposited by glacial meltwater streams are known as outwash till or stratified till. 119) 120) Eskers and kames are associated with meltwater streams; they are composed of stratified sand and gravel. 120) 121) Rapid surge movements of Earth's tectonic plates offer a convincing explanation for the advances and retreats of the Pleistocene ice sheets. 121) 122) The Pleistocene Epoch began about 6 million years ago. 122) 11 123) Most of Canada was covered by one or more of the large continental Pleistocene ice sheets, especially the Laurentide in the east and the Cordilleran in the west. 123) 124) Lake Winnipeg in Manitoba is the shrunken remnant of glacial Lake Agassiz which used to be the largest Pleistocene lake in North America. 124) 125) The great, Southern Hemisphere glaciation left Jurassic tills on parts of South America, India, and South Africa. 125) 126) Eccentricity, obliquity, and precession are three factors involved in the Milankovitch astronomic explanation of why the Pleistocene continental ice sheets alternately grew and shrank in size. 126) 127) Glaciation is episodic because it has occurred at various times in Earth history since the Precambrian, but periodic in detail because of the alternating glacial and interglacial stages as seen in the Pleistocene. 127) 12