CHAPTER 14

A shoreline can gain or lose sand. The amount of sediment available to a shoreline system is called its ______.

sediment budget

Repeat LIDAR surveys can be used to document the effect of hurricanes on barrier islands because ______.

sedimentation can be measured erosion can be measured houses can be located

Rapid increases and decreases in global sea level are related to ______.

the extent of continental ice sheets

What are reasons that a promontory will be more vulnerable to wave erosion than a bay?

A promontory will receive more wave action than a bay. Powerful waves focus most of their energy at a promontory. Waves bend around a promontory and strike it from both sides.

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- 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 - 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 - 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.

Why does sand move laterally along the coast (as in the image)?

Incoming waves move sand alternately inshore at an angle and then back offshore. Waves approach the coastline at an angle.

Match the condition with whether it generally causes an increase or decrease (or both) in the amount of sediment along a shoreline.

Increase - Runoff from streams Decrease - Erosion of sediment away from the shore by large storms Decrease or increase - Longshore current transportation of sediment parallel to the coast

A block of ice that is floating in a body of water melts completely. What happens to the water level?

It doesn't change.

Match the terms loading and unloading with the correct characteristics.

Loading - Downwarps the land surface; causes the land to lower relative to sea level Unloading - Results in isostatic rebound; occurs when weight is removed from the land; causes the land to rise relative to sea level

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 Northern Asia Canada Northern Europe

Changes in sea level may be caused by which of the following?

Ocean temperatures Rates of seafloor spreading Amount of continental glaciation Position of the continents

This image shows the amount of uplift interpreted for a northeastern Canada area over the last 6,000 years. What is the cause of this uplift?

Ongoing isostatic rebound has resulted from unloading.

Which of the following help scientists identify past glacial and interglacial periods?

Oxygen isotopic compositions in cores taken from glacial ice Oxygen and carbon isotopes in marine fossils

Which of the following are true of how proportions of oxygen isotopes are changed over interglacial and glacial periods in seawater and glacial ice?

Oxygen-16 is preferentially evaporated out of seawater. When glaciers accumulate on land, more oxygen-16 is locked away in glacial ice and does not make it back into seawater. When glaciers melt, oxygen-16-rich water is released back into seawater.

What type of evidence is left in lake sediments that helps us reconstruct climate change in the Great Lakes region during the Ice Age?

Pollen

Which of the following control the Milankovitch cycles that influence global climate?

Precession (the wobble of Earth's rotational axis) Eccentricity (the varying shape of Earth's orbit) Varying tilt angles of Earth

Match the type of erosion that occurs at a promontory or bay.

Promontory - Erosion is more intense because wave action is focused here, possible striking from all sides. Bay - Erosion is reduced due to quiet water; strong waves do not reach here.

Which of the following are true of how glaciers move?

Rates at which glaciers move are extremely variable (a few centimeters to tens of meters per day). The upper part of a glacier flows faster than the lower part. Only the coldest glaciers become locked to the bedrock at their base.

How do waves erode material from the shoreline?

- breaking directly on a rocky coast and swirling away loose pieces of bedrock - wearing away of bedrock with the crashing and grinding of water and sediment - smashing together loose pieces of rock and making large, angular rocks become smaller, rounded ones

Based on the LIDAR images of elevations (showing coastal Alabama post-Ivan and post-Katrina hurricanes), how has LIDAR data helped scientists understand this shoreline (high "boxes" represent houses)?

Data demonstrate that this coastline is at high risk for storm damage. Data show large changes in erosion and deposition of sediment in different areas along the coast.

Place the following statements in order from top to bottom to explain the development of a sea stack.

1. A promontory extends out into the sea 2. Wave action begins to erode at the weaker parts of the rock on the promontory 3. A sea cave is formed, as rock behind the tip of the promontory is eroded faster than the tip. 4. Continued erosion collapses the roof of the sea cave, leaving a passage behind the tip of the promontory. 5. A sea stack is created that was once the tip of the promontory.

Order the sediments formed in the surf zone by the general amount of time over which they have been eroded by wave action along the coast. Put the sediment formed in the shortest amount time on top and the sediment formed in the longest amount of time at the bottom.

1. Large, angular rock pieces 2. Sand 3. Flattened, smooth pebbles

Rank the coastal features in the order they form, with the first on top.

1. Promontory 2. Sea cave 3. Sea stack

Order the steps of glacier ice formation from snowflakes, beginning with the snowfall. Place the first step at the top and the last step at the bottom.

1. Snow falls as individual flakes. 2. Snowflakes are pressed together; air is forced out. 3. Snowflakes are compressed into irregular, dense spheres. 4. Snow changes into interlocking crystals and has a bluish color.

Match the activity to its climatic effect.

Decreased sunspot activity - Climate cools slightly Increased snow and ice cover on Earth - Increased albedo makes a cooler climate. Release of CO2 and CH4 into the atmosphere - More greenhouse gases tend to warm the planet Large volcanic eruptions - Ash and dust block sunlight, resulting in cooling

Order the systematic changes that occur in waves as they approach the shore, with the first event at the top and the last event at the bottom.

1. Water shears on the bottom when the depth is shallower than the wave base, as the waves approach the shore. 2. Waves slow down 3. Wave crests bunch up and become steep (wave height increases and wavelength decreases). 4. Wave crest topple over, and the wave breaks in the surf zone.

Calculate how much melting a block of ice (coming from outside the tub) will raise the water levels in this tub. The tub is 100 cm long by 40 cm wide, and the cube to be melted is 20 cm by 20 cm by 20 cm. The rise in water level is ______.

1.8 cm

If two successive wave crests are 30 m apart, what is the approximate depth of the wave base?

15m

They rate at which glaciers move varies widely, from a few centimeters a day to over ______ per day.

30 meters

How much higher will the water level in this tub be by melting a block of ice (coming from outside the tub)? The tub is 100 cm long by 40 cm wide, and the cube to be melted is 30 cm by 30 cm by 30 cm. The rise in water level will be about _________ cm.

6

If two successive wave troughs are 120 m apart, what is the approximate depth of the wave base?

60 m Reason: Depth of wave base = wavelength/2

Match the feature in the image with its description.

A (sediment) - Erosion of sediment down-current of a groin B (wall) - Breakwater D (sediment) - Accumulation of sediment up-current of a groin C (wall) - Groin

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.

Match the lettered area indicated on the image to the correct feature.

A - Cirque B - Tarn C - Hanging valley D - Arête

Match the lettered feature on the image with its name.

A - Esker B - Kettle lake C - Drumlin D - Recessional moraine E - Terminal moraine

Match the lettered areas in the images with their correct descriptions.

A - Ice cover close to a maximum; ice in the middle may have been several kilometers thick B - Ice ages ending

Match the lettered image with its appropriate description related to tide level.

A - It is high tide; the ocean is at its highest point relative to land. B - It is an average sea level; the ocean is at an intermediate height that occurs between high and low tide. C - It is low tide; the ocean is at its lowest level on a shoreline.

Correctly match the letter on the image, indicating the different types of moraines, with the correct name of that type of moraine.

A - Lateral moraine B - Medial moraine

Match the feature on the image with its name.

A - Spit B - Sandbar C - Barrier island

Match the lettered feature in the image with its description related to how it affects the shoreline.

A - Storms alter the strength of the waves, wind, and amount of rainfall; it may cause greater erosion and move larger clasts of sediment along the shore. E - A steeply sloped seafloor causes large waves to break directly against the shore, and greater erosion occurs. D - The orientation of the coast creates a sheltered area that receives less wave action. B - A rocky coastline is created by bedrock that is resistant to erosion.

Match the letter on the diagram with the corresponding term, distinguishing parts of an ocean wave.

A - Wave height B - Wavelength C - Depth of wave base - wavelength/2 D - Trough E - Crest

What is a glacial erratic?

A boulder transported and deposited by a glacier

What is permafrost?

A condition in which water in the uppermost part of the soil profile is permanently frozen

Which four factors are considered significant in causing the ice ages?

Amount of CO2 and methane in the atmosphere Changes in solar activity Position of the continents Changes in Earth's tilt and orbit around the Sun

Match the erosional glacial landform with its description.

Arête - This is a jagged ridge formed between two glaciers, as they are eroded from both sides. Tarn - This is a small lake in a glacially sourced depression. Hanging valley - The side valley is higher than the main valley because larger glaciers scour deeper into bedrock than smaller, side valley glaciers. U-shaped valley - The smoothing action of a glacier creates this large-scale feature. Cirque - A bowl-shaped depression is created as ice plucks pieces from the bedrock at the uppermost end of a mountain glacier.

Match the feature associated with a relative sea-level rise with its description.

B - Barrier islands have become totally submerged by rising seas. A - An estuary has been created where a river valley once existed. C - A new island has formed out of what was originally a hill.

The highest tides in the world are found in the ______, where the tidal range is as much as 16 m.

Bay of Fundy in Nova Scotia

Match the characteristic/feature of a glacier or glacial area with its description.

Blue Ice - This forms as snow gets buried and compressed. Crevasses - These are fractures in a glacier, formed as internal stresses cause is upper surface to break Rock powder - This is created as glacial movement grinds up pieces of surrounding rock. Grooves and streaks - These are created as sediment trapped in the glacier is being carried by the flow. Steep, exposed slopes - Snow and ice slide downhill and are not allowed to pile up.

On the image, identify the terminus of the glacier.

C

Match the letter in the diagram with the description of the progress of wave development at that location.

C - A gentle breeze forms small, disorganized B - Waves grow larger with stronger wind; long wavelength waves travel faster A - Strong wind causes waves to break and whitecaps to form

Sea-level fall may expose the following features along a coastline.

Coral reefs Wave-cut platform Wave-cut notch

Match the location on the glacier with the appropriate description.

D - Snow-covered zone of accumulation B - Blue-ice zone of ablation

Match the ice sheet in Antarctica with its characteristics.

East Antarctica - It is the larger ice sheet of the two and is based above sea level West Antarctica - It is the smaller ice sheet of the two and is based below sea level.

Determine which features are indicative of submergent coasts and which are indicative of emergent coasts and match them accordingly.

Emergent coasts - Marine terraces; wave-cut notches; exposed coral reefs Submergent coasts - Barrier islands; estuaries; fjords

What may be expected to happen to sediment along a beach during a storm?

Erosion of sand by large waves Movement of sand out to sea Deposition of sediment farther up the beach than normal

Determine whether the shoreline feature is a result of erosion and has been uplifted or is a result of deposition and has been submerged.

Erosion; uplift - Sea cliffs; wave-cut platforms; sea stacks; sea arches Deposition; submerged - Spits; baymouth bars; barrier islands

Match the feature with its description and how it may indicate the past presence of glaciers.

Erratic - 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 - It consists of a larger stone that is deposited in otherwise fine-grained marine and lake sediment; floating icebergs dropped the stone. Tillite - It consists of consolidated till and/or poorly sorted, glacially deposited sediment that has now become a sedimentary rock. Polished and scratched bedrock - 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

True or false: There was only one glacial and one interglacial period during the past 2 million years.

False

True or false: The only process responsible for the movement of sediment along a shoreline is water wave action.

False Reason: Wind is common along shorelines and may carry sand and finer materials long distances. Also, seacliff erosion can add significant amounts of sand to the shoreline.

Which of the following geologic features increase the risk of shoreline hazards?

Gentle sloping shoreline Narrow-width beaches Low river valley

Determine if the isotopic evidence indicates a glacial or an interglacial period by matching the period to the evidence.

Glacial period - Higher ratios of oxygen-18 to oxygen-16 in seawater and in the compositions of marine shells Interglacial period - 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 are some characteristics of glaciers and glacial areas?

Glaciers form where snow and ice accumulate faster than they melt. Glaciers flow. Glaciers may fracture, forming crevasses.

The remnants of the much larger glacial Lake Bonneville are the _________ ________Lake.

Great Salt

What area of the Northern Hemisphere, covered by ice 28,000 years ago, is also ice covered today?

Greenland

Based on what you know about the causes of high and low tides, match the type of tide that would be present with the individual locations in the situation depicted. Assume the Sun is to the left of the illustration.

High tide - A and C Low tide - B and D

Match the type of glacier with its description.

Ice sheets - Large, regionally continuous masses of ice more than 50,000 km^2 in area Alpine glaciers - Glaciers that begin in mountainous terrain Piedmont glaciers - Broad glacier that form when a more restricted glaciers spreads out, as it moves into less

Which of the following are true of LIDAR?

It is used to collect information about elevation. It employs a laser beam directed out of an airplane. Measurements over time may help show areas of erosion and deposition along shores.

Match the names of lakes that existed in glacial times with the features that remain today.

Lake Bonneville - Great Salt Lake; salt flats of the same name as the original lake Lake Missoula - Channeled Scablands Lake Lahontan - Smaller lakes in the low basins of western Nevada

Match the geologic feature with whether its presence marks a greater risk or lesser risk for hazards along a coastline and the associated reason behind that risk.

Large dunes - Lesser risk (particularly for those stabilized by vegetation); lowers the risk of erosion and risk from inland storm surge Sandbars and reefs - Lesser risk; protection of a coast from wave action by these barriers Gentle slope of the land adjacent to shore - Greater risk; allows the sea to wash farther into the land, potentially causing more flooding by storm surges Narrow beach - coastline Greater risk; allows erosion during storms, affecting structures sitting near the coastline

Match the name of the moraine with its description.

Lateral moraine - Forms along the sides of a glacier Medial moraine - Forms down the center of a glacier, when two tributary glaciers meet Terminal moraine - Forms at the farthest extent of a glacier's advance

How is sand moving (overall) in the diagram of the beach?

Laterally to the right Reason: This is called longshore drift.

Match the Milankovitch cycle change with its description.

Maximum tilt angle of Earth - 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 - It decreases the effect of the seasons. Cooler summers lead to an increase in glaciation. It cycles about every 40,000 years. Precession - Each cycle lasts about 23,000 years; this "wobble" may affect global climate. More eccentricity - Earth's orbit is slightly more elliptical; cycles last about 100,000 years. Less eccentricity - Earth's orbit is slightly more circular; cycles last about 100,000 years.

Match the factor with how it may affect sea level.

Melting of glaciers and ice sheets - Large volumes of water are released back into the ocean; sea level rises. Fast rates of seafloor spreading - Mid-ocean ridges become broader, and ocean water is displaced out of ocean basins; sea level rises. Cooler ocean temperatures - Water in the oceans will slightly contract; sea level drops Position of more continents near the poles - Glaciation becomes widespread; sea level drops

What occurs at a subglacial channel?

Meltwater flows along the base of a glacier.

If global sea levels rise, what could happen to West Antarctica?

More of the ice sheet could float and detach; collapsed parts would melt and raise sea level more.

Based on what you know and what you can see in the image, which of the following are true of Cape Cod?

Much of the sediment here was originally deposited by glaciers but then flooded and reworked, as global sea level rose. Barrier islands and smaller spits are present. A large spit curves and projects toward the north.

What landforms would you expect to see in the diagram after the glaciers melt completely away?

Narrow, sharp ridges High, sharp peaks U-shaped valleys

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.

Which of the following are true regarding the wave base?

No wave action occurs below this level. The depth to the wave base is about half the wavelength.

In North America, permafrost is located in ______.

Northern Canada Alaska

Which of the following methods could be used to return a shoreline system to its natural state?

Remove dams on rivers that supply sand. Restore wetlands and barrier islands.

In which of these situations would a beach generally see an increase in its sediment budget?

Rivers and deltas are present. Waves erode sediment from offshore reefs and islands. Large amounts of runoff from land occur.

Which of the following are common processes that alter the different sizes and shapes of sediments within the surf zone?

Rocks become smooth and flattened. Sand forms from broken rock particles. Angular rocks are rounded, as their corners are knocked off.

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 shoreline feature with the typical situation involved in its creation.

Rocky coast - Coastal land is made of hard rock that resists erosion. Coastal outline of narrow inlets and bays - A rise in relative sea level flooded river valleys along the submerging coast. Gentle slopes and rounded hills - Land materials are soft and easily eroded here, and available sediment is fine grained. Large amounts of soil and vegetation - A wet climate exists along the coast.

Match the shoreline feature with its cause via wave erosion.

Rounded sediment - Waves smash together loose rock, causing angular corners to wear away. Wave-cut notch - Crashing water and sediment wear away at bedrock along a rocky shoreline in the same place over time. Wave-cut platform - Waves wash sediment back and forth across the sea bottom and smooth off the underlying bedrock. Angular sediment - Waves break directly on the coast and swirl away loose, broken pieces of bedrock.

Complete the sentences by matching the phrases to correctly describe the relationship between changes in sea level and glaciation.

Sea level falls - when glaciers and ice sheets are extensive. Sea level goes up - when glaciers and ice sheets melt.

Match the engineered structure with its negative consequences on the coastline.

Seawall - Results in loss of the beach in front of the structure Jetty - Focuses waves on adjacent stretches of coast, causing erosion Groin - Blocks the longshore drift, causing erosion down current

Match the feature with how it may address shoreline problems.

Seawalls - They are built along the shore in an attempt to "armor" the coast against erosion; they commonly result in the loss of beach in front of the feature. Jetties - They jut out into the water to protect a bay, harbor, or beach; usually they are built in pairs to protect a shipping channel. Groins - They are placed perpendicular to the shore to influence lateral transport of sand by longshore currents; they trap sand on one side and often erode it on the other. Breakwaters - They are built parallel to the shore, in the water near the brunt of waves and currents; they may protect from erosion.

What approaches have been tried to address shoreline erosion problems?

Seawalls and breakwaters Not building along coasts Beach nourishment Jetties and groins

Which of the following statements are true regarding the sediment glaciers carry?

Sediment is largely unsorted and angular. Sediment that is carried and deposited by a glacier is a moraine. Some sediment is brought to glaciers by streams. The sides and base of glaciers have the most abundant sediment.

What are possible causes of sediment slumping offshore of the beach in the image?

Sediment may have been physically disturbed by wave action. The sea bottom may be too steep to hold the sediment. An earthquake may have disrupted the sediment.

Which of the following are true of the movement of sediment on a beach under normal (nonstormy) conditions?

Sediment on the sea bottom is churned up and carried shoreward. Sediment is reworked back and forth by waves but may not travel very far. Fine, dry sediment may be carried long distances by the wind.

Which factors may directly influence the strength of wave action (and therefore the strength of erosion and transportation/deposition of sediment) striking a coast?

Size and intensity of storms Slope of the seafloor Orientation of the coastline

Match the northeastern United States landscape features with the glacial process that formed them.

Smooth throughs - Erosion by the ice sheet and filling by river sediment Curved ridges - Piles of sediment deposited by melting glaciers Inlets and bays - Sea flooding the coastline after glaciers melted

What evidence exists for past glaciation and a colder climate in the United States?

Smoothed-off areas of bedrock Moraines and other glacial sediment Pollen records that show a change from colder to warmer climate plants Outcrops that display glacial scratches and polish

What are some hazards that exist along coastlines?

Storm surge Strong winds and rain; flooding Wave erosion, especially during storms

Between 20,000 and 10,000 years ago, which of the following occurred in North America?

The Great Lakes formed. The upper Mississippi River began to develop. Glacial ice retreated.

An estuary ______.

is influenced by rivers and the ocean would be located on a submergent coast

Ideally, how will the rubber duck (representing individual water particles in a wave) in the image move in comparison to the propagation of a series of waves moving toward the right?

The duck will follow a small circular path, continually returning to its original position as the waves propagate past.

Based upon your knowledge of glaciers, which of the following are true?

The equilibrium line sometimes is marked by a boundary between snow-covered ice upslope and bluish ice downslope. As a glacier moves downhill, it loses more and more ice by melting and sublimation. The zone of accumulation is higher in elevation than the zone of ablation.

Which are true of the ice in West Antarctica?

The ice sheet carries massive amounts of ice toward the sea and ice shelves. The central part is as thick as 3,500 m. The base of the ice sheet is below sea level. The ice shelves are losing large volumes of ice every year.

Based on the image and your knowledge of the relationship between melting ice and sea level, which of the following statements is true?

The melting of block A will appreciably raise the level of water in the tub.

Which of the following statements correctly describe the role of ocean currents and continental positions on glaciations and global climate?

Warm currents may either inhibit or increase glaciation. Upwelling ocean currents may bring cold water to the surface, helping to cool the adjacent landmasses. Cold ocean currents may inhibit the growth of glaciers by putting less moisture into the atmosphere.

Which of the following are true regarding the location of ice sheets and glaciers?

The second-largest ice mass is on Greenland. Most glaciers are in high latitudes or high elevations. The largest ice mass is on Antarctica.

Which of the following contribute to the breaking of a wave as it moves into shallow water?

The wave height increases, as the wavelength decreases. The lower parts of the wave shear against the bottom as the water is shallower than the wave base. The wave becomes too high and steep to support itself. The velocity of the wave slows, as it moves into the shore.

Which of the following pieces of evidence, supporting past glaciations in the United States, are visible in this image?

There are ridges that represent piles of glacial sediment (mostly moraines); these were deposited by the retreat of glaciers. There are smooth troughs that trend from northeast to southwest; these were smoothed off by movement of ice sheets.

Why are some coastlines sheltered from strong waves?

They are in a bay. They are situated behind an island. They form behind a barrier reef.

Which are true of tides?

They usually only vary between high and low levels by 1 to 3 m. In most places, high and low tides occur every 12 hours and 25 minutes. They are cyclic changes in the height of the sea surface.

From the list below, choose the descriptions of spring tides while leaving the descriptions of neap tides.

This is created when the Earth-Moon-Sun system is in alignment. High and low tides are more extreme than usual. It occurs at times of the new moon and full moon.

A flood ride is ______ and an ebb tide is ______.

rising; falling

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.

Which of the following are common processes that may affect shorelines?

Transport of sediment by rivers Fine sediment carried by wind Movement of waves and tides Deep- and shallow-water currents

True or false: Below the wave base there is no wave action (from surface waves).

True

True or false: Geologists use processes and features found in currently active glacial environments to help interpret landscapes left behind by ancient glacial events.

True

True or false: If a glacier has a smooth bedrock-glacier interface and/or that interface contains water from melting ice, that glacier is likely to move more rapidly than one that has an irregular interface and is frozen at its base.

True

True or false: One of the best ways to avoid shoreline hazards is not to build in those places that have the highest likelihood of erosion, flooding, landslides, and hazards.

True

How many ice sheets does Antarctica have?

Two Reason: There are three ice shelves surrounding Antarctica.

Which of the following will occur as a water wave continues to move to the right in the diagram shown?

Water at point B will move in a smaller diameter circular pattern than at point A. Water at point A will move in a clockwise circular pattern. Water at point C does not move at all.

Match the ocean wave term with its appropriate description.

Wave crest - The highest part of a waveform Wave trough - The lower part of a waveform Wavelength - The horizontal distance between two wave crest Wave height - The vertical distance between the wave crest and the wave through

Match the shoreline hazard with its best description.

Wave damage -It occurs mostly during hurricanes and storms and involves erosion of land and hillsides, causing slopes and buildings to collapse into the water. Storm surge - Strong winds pile up water in front of an approaching storm, inundating low-lying areas along the coast. Strong wind - Communities along a coast lack a windbreak between them and the open water, causing damage to be severe. Rainfall-related flooding - Many coastal areas are low-lying and flat, so structures are prone to inundation by water.

Match the shoreline feature with its description.

Wave-cut platform - It is formed when erosion at sea level bevels off bedrock and forms a flat surface that may be covered by water at high tide and fully exposed at low tide. Sea arch - It is formed when erosion cuts through small promontories jutting out to sea. Sandbar - It is formed as waves and longshore currents move sediment, and it may shift positions and is typically submerged. Marine terrace - It is formed by a wave-cut platform that is uplifted above sea level.

Match the process with its description regarding how it affects shorelines.

Waves - They are generated by wind. They erode rock and move and deposit sediment. Rivers - They are an important contributor of sediment from the land side. The deposition of sediment from them may form a delta. Winds - They move fine material on a beach. The transported sediment from them may form dunes. Faulting/tectonic activity - Over time, they may raise or lower parts of a coast relative to sea level, causing either emergence or submergence of the coast.

Why do initially straight water waves generally refract (bend) as they approach a shoreline?

Waves almost always approach the shore at an angle. Differences in velocity between segments of the wave cause the waves to bend and become more parallel with the shore. As waves approach shore, segments closest to shore slow down relative to those farther out.

Match the following processes with the correct description of the formation of a spit, baymouth bar, or barrier island.

Waves and longshore currents move sediment along the coast, building up a long, low mound of sediment. - Spit formation A long, low mound of sediment lengthens in the direction of the prevailing longshore current and becomes long enough that it cuts off a bay. - Baymouth bar formation Sea level rises around former long, low mounds of sediment and bay cutoffs. - Barrier island formation

Tremendous flood caused by the rupturing of ice dams created the Channeled ___________ in eastern Washington.

scablands

Which of the following are true of the action of wind along a shoreline?

Wind is more effective above the shoreline where the sand is dry and loose. Low- to moderate-strength wind cannot dislodge sand that is wet. Wind is common along shorelines.

One of the benefits of using LIDAR to survey an area is that ______.

a large area can be covered quickly

Not all large masses of ice are glaciers. A large accumulation of snow and ice that does not move is called ______. When large masses of ice form as the upper surface of the ocean freezes, that ice is called ______.

a snowfield; sea ice

The thin layer of unconsolidated material that forms on top of permafrost and occasionally thaws is the __________ layer.

active

The thin layer of unconsolidated material that forms on top of permafrost and occasionally thaws is the ____________ layer.

active

The bedrock of West Antarctica is visible ______.

along the coast and in the mountains

Glacial abrasion involves the ______.

scraping of bedrock with rock and smaller sized sediment found within a glacier's base

By studying current active glaciers and their associated features, we practice uniformitarianism by ______.

applying this information to understand glaciers in the geologic past

Snowfields and sea ice are large masses of ice and snow that _______ classified as glaciers.

are not

The ice ages ______.

are so called because over the past two million years, there was a marked increase in glacial periods coincide with the Pleistocene Epoch

Glacial ice forms ______.

as snowflakes are buried and compressed, eventually becoming crystalline ice

Glaciers move ______.

at highly variable rates

The West Antarctic ice sheet could ______ if see levels continue to rise

become detached from the underlying bedrock

The amount of sediment that a shoreline loses or gains is its sediment _____________.

budget

Large blocks of ice collapsing off the front of a glacier are said to be ______.

calving

At the leading edge of a glacier entering into a body of water, blocks of ice may break off in a process called ______. When these blocks are floating in the water, they are called ______.

calving; icebergs

A glacier ______.

can cover a continent is a moving mass of ice may be restricted to a single valley

A glacier that is calving is ______.

collapsing at the front, and large blocks of ice are breaking off

A glacier flowing over a steep drop-off or around a curve will develop cracks in its surface called __________.

crevasses

Cracks in the surface of a glacier are known as ______ and form in areas of dramatic slope change and where the ice flows around a curve.

crevasses

When seafloor spreading along a ridge is slow, over time there will be a(n) ______ in sea level.

decrease

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.

decrease; decrease

The process of plucking can lead to the ______.

sculpting of an asymmetric feature known as a roche moutonnée deposition of glacial erratics

Any sediment carried by ice, icebergs, or meltwater is called glacial _________.

drift

If the position of the continents is closer to the North or South Poles, global sea level ______.

drops, as more widespread glaciation occurs

Match the lettered feature in the image with its description related to how it affects the shoreline.

ebb; flood

Bodies of water become ______ in heavy oxygen (18O) during glacial periods.

enriched Reason: Right; the lighter O is preferentially evaporated and eventually tied up in ice, leaving more of the heavy oxygen behind.

The area on a glacier where the accumulation of ice and snow exactly balances the loss is called the ___________ line.

equilibrium

On a glacier, the area where the accumulation of ice and snow exactly balances the loss is called the ______.

equilibrium line

Structures designed to protect beaches often result in _____________ of sediment in other nearby locations thereby transferring the problem rather than solving it.

erosion OR loss

This is a glacial _________.

erratic

Chesapeake Bay is a(n) __________.

estuary

Water ______ when heated, causing sea levels to ______.

expands and takes up more volume; rise

If ocean temperatures fall, then sea levels _________.

fall

Sea level ______ when glaciers and ice sheets grow during ice ages.

falls

The Channeled Scablands in eastern Washington were formed during the last ice age when ______.

floodwaters caused rapid and large-scale erosion ice dam failures created enormous floods

Calculations of the effect of melting the West Antarctic Ice Sheet on global sea level are estimated at a 6 m rise. Much of the East Coast of the United States is at high risk in the event of sea level rise because of ______.

gentle slopes of the coast the presence of barrier islands low-elevation land

A time when glaciers are more widespread is called a(n) ______ period; a time when glaciers are melting and retreating is called a(n) ______ period.

glacial; interglacial

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) ___________.

glacier

The feature built in the water here is a ___________. Overall, the longshore current moves to the _________ causing sedimentation on the up-current side and erosion on the down-current side.

groin; right

The process of abrasion, where rock and smaller sized sediment at the glacier's base scrapes at underlying bedrock, may lead to glacial ______.

grooves striations

The Ice Age that began approximately 2 million years ago ______.

had many glacial and interglacial periods

This image shows a coastline that ______.

has undergone a rise in relative sea level

Continuous permafrost is located primarily in northern Canada and Alaska but also can be found in discontinuous _____________-elevation, mountainous regions in North America.

high

A coastal area will pass through two ______ tides every day.

high and low

The Bay of Fundy in Nova Scotia has the ______ tides in the world.

highest

A period of time in which large regions of land are covered year-round with ice and snow, especially in the last 2 million years, is called a(n) ______.

ice age

When a glacier encounters a sea or lake, ______.

ice along the leading edge of the glacier may calve and form icebergs it may float on the water a large ice shelf may be formed, if a large quantity of ice is floating on the water

Smooth troughs, curved ridges, and lakes in the Northeastern U.S. indicate that huge __________ ___________ once flowed across this area in the recent past.

ice sheets OR continental glaciers

Erratics, fossils of Arctic birds, and scratched bedrock in places far removed from glaciers helped to support the __________-__________ hypothesis.

ice-age

The time during an ice age that occurs between glacial periods, when glaciers are melting and retreating, is called a(n) ___________ period.

interglacial

The coastline in the image ______.

is an emergent coast shows an example of a marine terrace has undergone a relative fall in sea level

Glaciers can be the source of windblown silt called _________.

loess

Glaciers can be the source of windblown silt called ___________.

loess

The current that moves sand parallel to the coast is the _________ current.

longshore

The movement of a glacier through an area ______.

may carve grooves and scratch marks into bedrock locally polishes smooth surfaces onto bedrock wears down topographic highs

The hypothetical ____________ of the West Antarctic ice sheet would increase sea levels globally, causing massive flooding in paces such at the coastal eastern U.S.

melting

Rivers and streams flowing away from glaciers deposit ______.

outwash plains Reason: Wind = loess; terminal moraines = direct by glacier; Drumlins= underneath glaciers

What direction relative to the beach does the longshore current move?

parallel

The image shows ____________ ground, which consists of geometric patterns and forms above permafrost.

patterned

A condition in which water in the uppermost part of the ground remains frozen all or most of the time is _________.

permafrost

The process of __________ is concentrated on the downflow side of irregularities in the bedrock beneath a glacier and can occur where rocks become loosened by and incorporated into ice at the glacier's base.

plucking

The process of ___________ is concentrated on the downflow side of irregularities in the bedrock beneath a glacier and can occur where rocks become loosened by and incorporated into ice at the glacier's base.

plucking

This graph demonstrates that tree ____________ frequency (the x-axis) preserved in lake beds can be used to understand how climate warmed in the Great Lakes and Northeast over the last 12,000 years.

pollen

The Ice-Age hypothesis developed from ______.

presence of scratched and polished bedrock far beyond the Alps evidence of bones of reindeer and Arctic birds in southern France the large, out-of-place erratics scattered across much of Europe

These waves bend, or ___________, as they approach the shore because the run into the bottom and __________ in speed.

refract; decrease

If seafloor spreading along a ridge is ______, the ridge becomes broad, displacing water out of the ocean basin and increasing sea level.

relatively fast

When continental ice sheet recede, sea levels ___________.

rise

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.)

sheets; alpine; piedmont

Earth shaking or large storm waves may cause sand to move offshore along the sea bottom in a process called _________.

slumping

Earth shaking or large storm waves may cause sand to move offshore along the sea bottom in a process called ___________.

slumping

The curled fist of Cape Cod is a _________ of glacial sediment reworked by the __________ current.

spit; longshore

Meltwater flows along the base of a glacier in a(n) ____________channel.

subglacial

Coasts that form where the land has been inundated by the sea due to a relative rise in sea level are ______ coasts; ones that form where the land experiences a relative drop in sea level are ______ coasts.

submergent; emergent

Cold ocean currents can ______ the growth of glaciers by cooling the land and ______ the growth of glaciers by having supporting low atmospheric humidity.

support; hinder

The lower end of a glacier, where the glacier ends either on land or in the sea, is the __________.

terminus

Most of the sediment that glaciers carry comes from ______.

the slopes that flank the glacier and the bedrock below the glacier

In the past, global sea level was lower because ______.

there was more widespread glaciation, as one or more of the continents were nearer to the poles than they are today

Ancient glaciation events are indicated by the presence of ______.

tillite dropstones ridges of moraine, eskers, and drumlins erratics

Glaciers move, or ___________ sediment of all sizes within, on top of, and underneath the moving ice.

transport, carry, OR entrain

Most coastal areas experience __________ high and _________ low tides each day.

two; two

Indicative of the carving and eroding of the original V-shaped river valley, glaciers create ___________-shaped valleys.

u

Sediment that is transported ______ a glacier is most likely to be ground to a very fine powder called rock flour.

underneath

Most surface ocean waves are caused by ______.

wind blowing across the surface of the water