Chapter 14 ReadingAssignment
Which of the following help scientists identify past glacial and interglacial periods?
-Oxygen and carbon isotopes in marine fossils -Oxygen isotopic compositions in cores taken from glacial ice
How does a glacier, at its base and sides, modify a bedrock valley?
-Rocks carried by glaciers grind and scrape the rock surface. -The rock beneath may be smoothed, polished, and scratched. -Sediment is left behind on the sides and bottom of the valley.
Match the type of glacier with its description.
Ice sheets <> Large, regionally continuous masses of ice more than 50,000 km2 in area Alpine glaciers <> Glaciers that begin in mountainous terrain and flow down valleys Piedmont glaciers <> Broad glaciers that form when a more restricted glacier spreads out, as it moves into less confined topography
Determine if the isotopic evidence indicates a glacial or an interglacial period by matching the period to the evidence.
Glacial period matches Choice, Higher ratios of oxygen-18 to oxygen-16 in seawater and in the compositions of marine shells Higher ratios of oxygen-18 to oxygen-16 in seawater and in the compositions of marine shells Interglacial period matches Choice, Lower ratios of oxygen-18 to oxygen-16 in seawater and in the compositions of marine shells. Lower ratios of oxygen-18 to oxygen-16 in seawater and in the compositions of marine shells.
Match the type of glacial deposit with its correct characteristics.
Glacial till <> Material deposited directly by ice that is generally unsorted and unstratified Glaciofluvial deposits <> Material deposited by glacial streams that is generally sorted and stratified Glacial drift <> Any sediment carried by ice, icebergs, or meltwater
What area of the Northern Hemisphere, covered by ice 28,000 years ago, is also ice covered today?
Greenland
Which of the following will occur as a water wave continues to move to the right in the diagram shown?
Movement of waves and tides Fine sediment carried by wind Deep- and shallow-water currents Transport of sediment by rivers
Which of the following best describes the composition of the atmosphere and the amount of energy given off by the Sun, both of which affect Earth's global climate?
Neither one is constant over time.
What land areas were largely covered by a large continuous ice sheet 28,000 years ago but are not largely covered by an ice sheet today?
Northern United States Canada Northern Asia Northern Europe
What evidence exists for past glaciation and a colder climate in the United States?
Pollen records that show a change from colder to warmer climate plants Moraines and other glacial sediment Outcrops that display glacial scratches and polish Smoothed-off areas of bedrock
A glacier that is calving is ______.
collapsing at the front, and large blocks of ice are breaking off
On a glacier, the area where the accumulation of ice and snow exactly balances the loss is called the ______.
equilibrium line
The Channeled Scablands in eastern Washington were formed during the last ice age when ______.
ice dam failures created enormous floods floodwaters caused rapid and large-scale erosion
The movement of a glacier through an area ______.
locally polishes smooth surfaces onto bedrock wears down topographic highs may carve grooves and scratch marks into bedrock
Rapid increases and decreases in global sea level are related to ______.
the extent of continental ice sheets
Sediment that is transported ______ a glacier is most likely to be ground to a very fine powder called rock flour.
underneath
Rivers and streams flowing away from glaciers deposit ______.
outwash plains
Which of the following pieces of evidence, supporting past glaciations in the United States, are visible in this image?
-There are smooth troughs that trend from northeast to southwest; these were smoothed off by movement of ice sheets. -There are ridges that represent piles of glacial sediment (mostly moraines); these were deposited by the retreat of glaciers.
A glacier ______.
-is a moving mass of ice -may be restricted to a single valley -can cover a continent
They rate at which glaciers move varies widely, from a few centimeters a day to over ______ per day.
30 meters
Match the lettered locations on the image, and the corresponding hypothetical locations of the Moon relative to Earth and the Sun, with the type of tide coastal areas on Earth would experience there.
A matches Choice, A spring tide would be experienced; the Sun's and Moon's gravity pull the ocean in the same direction to cause more extreme tides than usual. A spring tide would be experienced; the Sun's and Moon's gravity pull the ocean in the same direction to cause more extreme tides than usual. B matches Choice, A neap tide would be experienced; the Moon and Sun's gravity are at right angles and pull against each other to create weaker tides than usual. A neap tide would be experienced; the Moon and Sun's gravity are at right angles and pull against each other to create weaker tides than usual. C matches Choice, A spring tide would be experienced; forces on the Moon and Sun's gravity are aligned and more extreme tides are created, even though the Moon is on the opposite side of the Sun from Earth. A spring tide would be experienced; forces on the Moon and Sun's gravity are aligned and more extreme tides are created, even though the Moon is on the opposite side of the Sun from Earth.
Match the lettered feature on the image with its name.
A matches Choice, Esker Esker B matches Choice, Kettle lake Kettle lake C matches Choice, Drumlin Drumlin D matches Choice, Recessional moraine Recessional moraine E matches Choice, Terminal moraine Terminal moraine
Match the lettered areas in the images with their correct descriptions.
A matches Choice, Ice cover close to a maximum; ice in the middle may have been several kilometers thick Ice cover close to a maximum; ice in the middle may have been several kilometers thick B matches Choice, Ice ages ending Ice ages ending
Match the locations on the image with descriptions of glaciers present there.
A <> Antarctica: it is the largest ice mass on Earth and has mostly ice sheets with some valley glaciers. B <> Andes (especially Patagonia): glaciers occupy high peaks, mostly in the southern part of the mountain range. C <> North America: glaciers are present mainly in the higher peaks in the west. D <> Greenland: large ice sheets and smaller glaciers occupy 80% of this landmass. E <> Tibetan Plateau and the Himalaya: glaciers cover many of the highest parts of this area.
What is a glacial erratic?
A boulder transported and deposited by a glacier
Tremendous flood caused by the rupturing of ice dams created the Channeled in eastern Washington.
Blank 1: Scablands
Indicative of the carving and eroding of the original V-shaped river valley, glaciers create -shaped valleys.
Blank 1: U
In North America, permafrost is located in ______.
Alaska Northern Canada
Alone, these factors likely would not cause an ice age, but if occurring simultaneously, a(n) in the amount of greenhouse gases, a(n) in solar activity, and an increase in volcanic ash in the atmosphere could lead to significant global cooling.
Blank 1: decrease or decline Blank 2: decrease or decline
Any sediment carried by ice, icebergs, or meltwater is called glacial .
Blank 1: drift
The area on a glacier where the accumulation of ice and snow exactly balances the loss is called the line.
Blank 1: equilibrium or snow
This is a glacial .
Blank 1: erratic
A moving mass of ice, which may range in size from a huge ice sheet that covers large regions to a smaller mass that is restricted to a single mountain or valley, is called a(n) .
Blank 1: glacier
Continuous permafrost is located primarily in northern Canada and Alaska but also can be found in discontinuous -elevation, mountainous regions in North America.
Blank 1: high or higher
When continental ice sheet recede, sea levels . (Use just one word for your answer.)
Blank 1: increase or rise
Glaciers can be the source of windblown silt called .
Blank 1: loess
The largest accumulations of ice are in glaciers we call ice . Glaciers that flow down valleys in mountainous regions are , cirque, or valley glaciers. When either of these two glacial types spread out in less confined topography, they are glaciers. (Use just one word for each answer.)
Blank 1: sheets Blank 2: Alpine Blank 3: piedmont
Glaciers move, or sediment of all sizes within, on top of, and underneath the moving ice.
Blank 1: transport, carry, or entrain
Which four factors are considered significant in causing the ice ages?
Changes in solar activity Position of the continents Changes in Earth's tilt and orbit around the Sun Amount of CO2 and methane in the atmosphere
Match the activity to its climatic effect.
Decreased sunspot activity matches Choice, Climate cools slightly. Climate cools slightly. Increased snow and ice cover on Earth matches Choice, Increased albedo makes a cooler climate. Increased albedo makes a cooler climate. Release of CO2 and CH4 into the atmosphere matches Choice, More greenhouse gases tend to warm the planet. More greenhouse gases tend to warm the planet. Large volcanic eruptions matches Choice, Ash and dust block sunlight, resulting in cooling. Ash and dust block sunlight, resulting in cooling.
Match the feature with its description and how it may indicate the past presence of glaciers.
Erratic matches Choice, It may consist of a huge out-of-place block deposited on a landscape; glaciers transport huge rocks to places where such rock types are not present in the bedrock. It may consist of a huge out-of-place block deposited on a landscape; glaciers transport huge rocks to places where such rock types are not present in the bedrock. Dropstone matches Choice, It consists of a larger stone that is deposited in otherwise fine-grained marine and lake sediment; floating icebergs dropped the stone. It consists of a larger stone that is deposited in otherwise fine-grained marine and lake sediment; floating icebergs dropped the stone. Tillite matches Choice, It consists of consolidated till and/or poorly sorted, glacially deposited sediment that has now become a sedimentary rock. It consists of consolidated till and/or poorly sorted, glacially deposited sediment that has now become a sedimentary rock. Polished and scratched bedrock matches Choice, It consists of bedrock that has been smoothed and grooved; glacially carried sediment erodes away at the bedrock below. It consists of bedrock that has been smoothed and grooved; glacially carried sediment erodes away at the bedrock below.
Match the glacial features with their descriptions.
Eskers <> Long, sinuous ridges deposited by a meltwater stream beneath a glacier as it retreats Kettle lake <> Formed as a block of ice left behind by a glacier melts, leaving a depression that fills with water Glacial outwash <> River-carried sediment that may either be deposited near to or distant from a retreating glacier Recessional moraine <> Forms as the front of a glacier melts back and stagnates for some period of time in one location, depositing a pile of sediment Till <> The general name given to deposited glacial sediment Drumlins <> Streamlined hills formed as a moving glacier sculpts material into this shape
Match the Milankovitch cycle change with its description.
Maximum tilt angle of Earth matches Choice, It increases the effects of the seasons. Warmer summer temperatures melt more polar ice. It cycles about every 40,000 years. It increases the effects of the seasons. Warmer summer temperatures melt more polar ice. It cycles about every 40,000 years. Minimum tilt angle of Earth matches Choice, It decreases the effect of the seasons. Cooler summers lead to an increase in glaciation. It cycles about every 40,000 years. It decreases the effect of the seasons. Cooler summers lead to an increase in glaciation. It cycles about every 40,000 years. Precession matches Choice, Each cycle lasts about 23,000 years; this "wobble" may affect global climate. Each cycle lasts about 23,000 years; this "wobble" may affect global climate. More eccentricity matches Choice, Earth's orbit is slightly more elliptical; cycles last about 100,000 years. Earth's orbit is slightly more elliptical; cycles last about 100,000 years. Less eccentricity matches Choice, Earth's orbit is slightly more circular; cycles last about 100,000 years. Earth's orbit is slightly more circular; cycles last about 100,000 years.
Between 20,000 and 10,000 years ago, which of the following occurred in North America?
The Great Lakes formed. Glacial ice retreated. The upper Mississippi River began to develop.
Which of the following are true regarding the location of ice sheets and glaciers?
The second-largest ice mass is on Greenland. The largest ice mass is on Antarctica. Most glaciers are in high latitudes or high elevations.
Which of the following statements are true regarding the causes of tides?
Tides are primarily due to the gravitational pull of the Moon. High tides occur on the side of Earth facing the Moon, due to the pull of gravity on the oceans. High tides occur on the side of Earth facing away from the Moon, as water bulges out due to a decreased force of gravity from the Moon.
What landforms would you expect to see in the diagram after the glaciers melt completely away?
U-shaped valleys Narrow, sharp ridges High, sharp peaks
Which of the following control the Milankovitch cycles that influence global climate?
Varying tilt angles of Earth Eccentricity (the varying shape of Earth's orbit) Precession (the wobble of Earth's rotational axis)
Which of the following are common processes that may affect shorelines?
Water at point A will move in a clockwise circular pattern. Water at point C does not move at all. Water at point B will move in a smaller diameter circular pattern than at point A.
Match the process with its description regarding how it affects shorelines.
Waves matches Choice, They are generated by wind. They erode rock and move and deposit sediment. They are generated by wind. They erode rock and move and deposit sediment. Rivers matches Choice, They are an important contributor of sediment from the land side. The deposition of sediment from them may form a delta. They are an important contributor of sediment from the land side. The deposition of sediment from them may form a delta. Winds matches Choice, They move fine material on a beach. The transported sediment from them may form dunes. They move fine material on a beach. The transported sediment from them may form dunes. Faulting/tectonic activity matches Choice, Over time, they may raise or lower parts of a coast relative to sea level, causing either emergence or submergence of the coast. Over time, they may raise or lower parts of a coast relative to sea level, causing either emergence or submergence of the coast. Currents matches Choice, They may move either shallow or deeper level water and transport sediment along a coast. They may move either shallow or deeper level water and transport sediment along a coast.
Glaciers move ______.
at highly variable rates
Large blocks of ice collapsing off the front of a glacier are said to be ______.
calving
Ancient glaciation events are indicated by the presence of ______.
dropstones ridges of moraine, eskers, and drumlins tillite erratics