Earth- An Introduction to Physical Geology #4

Which of the following statements about deposition and erosion around meander loops is true?

- Erosion occurs where water is moving the fastest along the outside of the loop. - Deposition occurs where water is moving the slowest along the inside of the loop.

Zoning regulation

-------- is/ are cheap to implement, but it/they can adversely affect property values.

Why are researchers exploring the use of the radish as a cover crop?

It may be able to conserve most fall-applied nitrogen on the same fields where it is applied, thus preventing nutrient runoff.

Look at the four images of various river channels, and examine their unique characteristics and the dominant force or processes at work in each scene.

Left to right -Braided Alluvial Channel -Meandering Alluvial Channel -Non-meandering Alluvial Channel -Bedrock

In the diagram below, there are examples of five different landscapes. For each landscape, determine whether you have enough information to tell what type of stream drainage pattern would develop on it. If so, associate the landscape with the correct name of its drainage pattern.

Left to right: Dendritic Pattern Radial Pattern Rectangular Pattern Trellis Pattern Indistinct or multiple drainge

________ is fine silt generated by glaciers that can be carried for long distances by the wind.

Loess

A stream with a low to moderate gradient, varying most of its load in suspension should have

Meanders

How are medial moraines and lateral moraines related to each other, and in what setting do they form?

Medial and lateral moraines are linear landforms that are produced by alpine glaciers. Lateral moraines are deposited along the valley walls, whereas medial moraines result from the merging of two glaciers, their lateral moraines combining to form a medial moraine.

Which of the following budget scenarios describes a glacial advance?

More ice and snow accumulates than melts each year.

A delta forms here, where the velocity of the water flow decreases and deposition is highest

Mouth

How does the formation of a natural levee impact flooding?

Natural levees raise the height of the stream channel, reducing the amount of flooding that will occur on the floodplain.

Why is the northern Gulf of Mexico described as a "dead zone"?

Nutrient enrichment starts a chain of events that depletes the water of oxygen, making it difficult for aquatic life to survive.

Glaciers form because of the accumulation of large amounts of ice and snow. Which of the following provides the most water needed to create glaciers?

Oceans

________ are stratified sands and gravels carried away from the glacial terminus by meltwater.

Outwash

Distinguish between outwash deposits and ice-contact deposits.

Outwash deposits are deposited by meltwater streams beyond the terminus of a glacier, whereas ice-contact deposits accumulate on, within, or immediately adjacent to a glacier.

Drag the terms on the left to the appropriate blanks on the right.

Outwash plain −− Sands and gravels End moraine −− Till Erratic −− Solid rock Esker −− Sands and gravels Drumlin −− Till Arête −− Solid rock

InterGlacial Period

Period of milder, more temperate climates

De-Glaciation

Period of time when ice sheets and valley glaciers "retreat" significantly (ice sheets may or may not disappear)

How does an end moraine form?

Pieces of rock are transported to the front of a glacier as ice within the glacier moves.

Name the two main primary processes of glacial erosion:

Plucking and Abrasion

What kind of lake was Lake Agassiz in this image?

Proglacial lake

________ is an elevation point above which snow remains throughout the year.

Snowline

Are stream terraces depositional or erosional landforms?

Stream terraces can be either depositional or erosional.

What evidence of glacial erosion is visible in this image?

Striations

Which moraine marks the furthest extent of glacial ice?

Terminal Moraine

Which of the following changes is the result of glacier retreat following the last Ice Age?

The Channeled Scablands formed as Lake Missoula drained.

Which path(s), if any, are drawn across a section of the valley that was formed largely by glacial ice? Which path(s), if any, are drawn across a section of the valley that was formed largely by running water?

The Profile A path is drawn across a valley that was formed largely by glacial ice. The Profile B path is drawn across a valley that was formed largely by running water.

How would you expect the front of a glacier to move if it undergoes a period of net accumulation, followed by net wastage, and finally a period of net accumulation?

The glacier's front would move forward, backward, and then forward again.

How would a snow line on a glacier move as a glacial front is advancing?

The snow line would move downslope.

Under what circumstances will the front of a glacier advance, retreat, or remain stationary?

The terminus of a glacier advances if there is more accumulation than ablation, retreats if there is more ablation than accumulation, and remains stationary if accumulation is balanced with ablation.

How does the shape of the valley along the Profile B path compare to that of the Profile A path?

The valley along the Profile A path is U-shaped. The valley along the Profile B path is V-shaped.

True or False: Two 100-year floods can occur in the same year.

True

Zone on transportation

Trunk Stream Moderate Channel Size Moderate Volume Meander

What is the best way to describe the shape of a glacial valley?

U shaped

What is a flood?

When discharge in a river exceeds the river's capacity

Will plucking occur if a glacier is NOT advancing?

Yes, because glacial ice is still moving inside the glacier even if the glacier's front is not advancing.

Ice sheet

a large, massive glacier that moves independently of the topography.

Valley glacier

a long, narrow glacier that flows downslope.

What is a stream terrace?

a remnant of an older floodplain that sits above the stream valley

What is an end moraine?

a ridge of debris deposited at the end of a glacier

What is a natural levee?

a ridge of flood deposits next to a river channel

Lateral and medial moraines are found in connection with ________ glaciation.

alpine

Cirque

an amphitheater-shaped basin at the head of a glaciated valley produced by frost wedging and plucking.

The area outlined in orange is a(n) __________, which is an apron of sediment formed by neighboring __________.

bajada; alluvial fans

Which type of glacial movement is circled in Figure 1?

basal sliding

Particles moving by saltation are transported in the _______ load.

bed

What are the three types of loads carried by streams?

bed load, suspended load, dissolved load

________ is the maximum load of solid particles a stream can transport per unit time.

capacity

A(n) ________ flood will occur when an engineered structure fails and releases large quantities of stored water.

dam-failure

Select all those properties from the list that INCREASE as you move downstream in a river.

discharge, velocity

Which way does ice flow in a glacier retreating uphill?

downslope

The geographical area that is drained by a river and that contributes water to a river system

drainage basin

What glacial landform is visible in Figure 1?

drumlin

Describe the erosion occurring during headward erosion.

erosion backwards at the start of the stream

What are water gaps?

erosion through hills or ridges caused by a change in base level

Flooded glacial troughs along shorelines are called ____________ (single-word answer)

fjord

________ are flat areas along streams that are created by the deposition of alluvium and is subject to periodic inundation.

floodplains

During a glacial retreat, a glacier will flow _____ while the terminus moves _____.

forward; backward

A(n) ________ stream is a stream that is in equilibrium and is neither eroding or depositing material, but simply transporting it.

graded stream

In glaciated terrain, waterfalls are associated with ______.

hanging valleys

In which part of a stream's course would one typically find bedrock channels?

headwaters

What glacial feature is circled in Figure 2?

horn

Which choice below is a type of glacier?

ice cap valley glacier ice sheet piedmont glacier

A(n) ________ flood is most often associated with northward-flowing rivers in the Northern Hemisphere because the upstream stretches of the river will thaw before the downstream.

ice-jam

Where do glaciers form?

in places where more snow falls in the winter than melts away in the summer

Where are pebbles transported by streams?

in the bed load

Glacial stagnation

incoming ice is equal to ablation.

Glacial advance

incoming ice is greater than ablation.

Glacial retreat

incoming ice is less than ablation.

Which type of glacial movement will be responsible for the greatest amount of glacial flow?

internal flow

What is meant by a nonstructural approach to flood control?

limiting certain activities or land uses and implementing appropriate zoning regulations in high-risk flood areas

Which of the following is a characteristic of a graded stream? CHOOSE ALL THAT APPLY.

meanders well-developed floodplain

What is the name of the landform located at placemark K?

outwash plain

__________ are defined as a chain of glacial lakes where each lake flows into the next.

pater noster lake

Placemarks A through F indicate the locations of six different glacial formations. Which answer correctly identifies each of the formations?

placemark A: horn peak placemark B: arête placemark C: col placemark D: tarn placemark E: cirque placemark F: hanging valley

Glacial till is:

poorly sorted, poorly stratified

Which of the following terms best identifies the feature located at the Glacial Deposition placemark?

recessional moraine

The Great Flood of 1993 in the Upper Mississippi River basin is an example of which type of flood?

regional flood

Based on the historical imagery at the location in the folder, how far did the glacier advance or retreat between 1996 and 2005?

retreated approximately 750 meters

How can pieces of rock in contact with a stream bed move?

rolling, sliding, bouncing

Ice shelves are grounded in ________ and float in ________.

shallow water; deep water

Alluvial fans occur where a _____ exits the _____ and enters the _____.

stream, mountains, basin

What feature is responsible for creating eskers?

streams that flowed below, in, or on the glacier

The glacial erosion feature shown in the image is called "glacial _________".

striations

What is the name of the landform located at placemark J?

terminal moraine

Which landform marks the furthest extent of an advancing glacier?

terminal moraine

What is the snowline?

the elevation above which snow persists throughout the year

What is suspended load?

the fine-grained particles that travel in the water column above the stream bed

Which is the best definition of glacial snow line?

the line dividing zones of accumulation and melting of ice at the surface of a glacier

Imagine a valley containing four stream terraces. Where would the youngest stream terrace be found?

the lowest terrace

What is the zone of wastage?

the part of a glacier where snow melting exceeds snow accumulation

Which of the following is a characteristic of glacial till?

the particles are often scratched and polished

When do streams erode laterally?

when downcutting is occurring in easy-to-erode sediment or rock

When do stream terraces form?

when streams exist under alternating erosional and depositional conditions

What are the three main zones of a river system from highest to lowest?

zone of sediment production, zone of transportation, and zone of deposition

Part F - Features of Alluvial Fans Part completeA fan in Death Valley, California is shown in the photos below. Use the information you learned from the video to fill in the sentence blanks.

1. The cross-fan profile is concave down. 2. The inactive portion of the fan is outlined in yellow. 3. A(n) decrease in water velocity causes sediment to be deposited on the fan. 4. The active portion of the fan is outlined in blue.

What is the minimum velocity needed for a 0.8 mm sand particle transition from a state of deposition to transportation?

5 cm/sec

Which of the placemarked locations in the Glacier Types folder shows a piedmont glacier?

A

Which of the placemarked locations in the folder would not have been covered by a continental ice sheet during Pleistocene Glaciation?

A

Why are urban areas susceptible to flash floods?

A high percentage of the surface area is covered with cement, asphalt, and other impervious materials

What is a pluvial lake?

A lake that fills in an arid/semiarid region due to increased precipitation in a cooler, wetter climate

Glacier

A mass of glacial ice that forms on land and shows evidence of movement.

Glaciation

A period of time during which ice sheets grow and expand out over vast areas of the continent

Contrast proglacial lakes and pluvial lakes, and give an example of each.

A proglacial lake, such as Lake Agassiz, was formed by glacial meltwater at the terminus of a glacier. A pluvial lake, such as Lake Bonneville, is formed from a decrease in evaporation in the presence of moderate precipitation as glaciation causes temperatures to lower.

artificial levee

A(n) -----confines water flow and can experience significant erosion. Constant maintenance is required.

At which of the following locations is erosion occurring?

A, C, E

What is the difference between an end moraine and a ground moraine, and how do they relate to the budget of a glacier?

An end moraine is a ridge of till that forms at the terminus of a glacier when the glacial budget is at equilibrium. A ground moraine is a layer of till that is deposited as ice melts when glacial ablation exceeds accumulation.

How does an oxbow lake form?

An oxbow lake forms when the bend of a meandering river is isolated from the river because erosional forces create a cutoff in the main river channel. This isolated bend becomes the oxbow lake.

Which two regions currently contain the world's last remaining ice sheets?

Antarctica and Greenland

What glacial feature is circled in Figure 1?

Arete

Which of the placemarks in the Alpine Landforms folder represents a tarn?

B

Which of the polygons in the Runoff folder would likely have the greatest amount of surface runoff during a rain event?

B

Highly affected by the velocity of stream

Bed Load

dam

Besides flood control, a(n)---- can also be used to generate hydroelectric power. However, they are expensive to build and maintain.

Non-structural approach

Best approach to flood control is to limit development within the floodplains

A ________ stream consists of a complex network of converging and diverging channels that weave around channel bars.

Braided streams

Which of the placemarked locations in the Glacier Types folder shows a cirque glacier?

C

Which of the placemarks in the Alpine Landforms folder represents an arête?

C

Which of the placemarks in the Lateral Moraine folder represents a lateral moraine?

C

Complete this analogy: Bouncing is to sand as suspension is to_____________.

Clay

________ is a measure of a stream's ability to transport particles based on size rather than quantity.

Competence

Which of the colored lines shown in the Equilibrium Line folder is the best choice for the location of the equilibrium line for this glacier?

D

Which of the placemarks in the Water Diversion folder does not include the alteration of surface stream flow for the purpose of agriculture?

D

Which portion of the stream is the most likely to become an oxbow lake in the near future?

D

The volume of water flowing past a certain point in a given amount of time is a rivers

Discharge

Unaffected by the velocity of stream

Dissolved Load

Artificial levees

Earth mounds built on river banks to increase the capacity of the channel Often fail in floods

Why have local nutrient reduction strategies been slow to be implemented?

Farming is a business and nutrient reduction likely will not occur unless there is a clear economic benefit to doing so.

From where do the majority of the nutrients found in the northern Gulf of Mexico originate?

Farms located in the American Midwest

Under what conditions will the front of a glacier remain stationary?

Glacial fronts remain stationary when melting and snow accumulation are equal.

Look at the two graphs below. Label each graph with the scenario it most likely represents. Notice that for each graph, a similar rainstorm occurs, releasing a certain amount of water into the environment. The horizontal (x) axis represents time. The light blue curve shows the amount of streamflow (called river discharge) in each environment.

Graph with tall peak: Flooding in an urban area; This setting is more likely to produce flash floods; Concrete surfaces mean water flows directly to the stream or river after a storm. Graph with small peak: Flooding in a rural area; Abundant open farmland allows for infiltration of water into the ground.

Complete this analogy: Sliding is to gravel as dissolution is to_____________.

Ions

Which answer most accurately describes the appearance and function of the landform at placemark J? It may be helpful to turn the Turquoise Lake Map overlay off and on as you explore the area.

It is an arc-shaped mound of material that blocks the outlet of the valley to the west. It appears to be a natural dam at the foot of the glacial valley that contains Turquoise Lake.

What are the origin and composition of the material that composes the landform at placemark J?

It is composed of an unsorted mix of rock material weathered, eroded, and deposited by the melting glaciers that flowed out of the cirques at placemarks I.

What is the origin and composition of the material that composes the landform at placemark K?

It is composed of well-sorted, fine particles of rock material that were weathered, eroded, and deposited by glacial meltwater from glaciers above the plain.

How are the valleys in this area shaped?

Almost all of the valleys are U-shaped.

What is a floodplain?

a flat surface next to a river channel

Channelization

Altering a stream channel to make flow more efficient - Increases erosion

What are the effects of Ice Age glaciers besides the formation of major erosional and depositional features?

-sea-level changes -the creation of proglacial lakes -crustal subsidence and rebound -changes to rivers and valleys -pluvial lakes

What is the term for sediment deposited by streams?

Alluvium

channelization

. Removing obstructions from a river channel is a form of a(n) -----------. It can make a river more navigable, but may also increase bank erosion due to increased water flow.

Direction and location of stream-flow controlled primarily by geology

-Solid bedrock that is fractured in some areas -Areas of hard rocks interspersed with areas of softer rocks

When was the last time North America had major ice sheets?

18,000 years ago

Which method of glacial erosion is responsible for the marks in this image?

Abrasion

How do fjords relate to glacial troughs?

Fjords are glacial troughs that became submerged as the ice left the valleys and the sea levels rose.

Look at the accompanying graph, and read the following statements regarding the time relationship between rainstorms and flooding. Based on this graph, which of the statements are true?

Flooding correlates with increased stream discharge. Peak stream flow happens after a storm.

How does a glacier lose ice through sublimation?

Ice changes from solid to gas.

Explain why post A has moved farther than posts B and C.

Ice in the center of a glacier has the least friction with the surrounding bedrock and can flow faster.

Which of the following locations does not currently have glaciers?

Scotland

Why would construction businesses find eskers to be economically important?

They provide easily accessible sand and gravel deposits

Based on your evaluation of imagery in the Helheim Glacier folder, identify the statement that is most strongly supported.

This glacier is flowing in a predominantly west to east direction but it is retreating in an east to west direction.

Identify the statement that is most strongly supported by the evidence seen in the landscape associated with the Past Glacial Processes placemark.

This location is a remnant of a Pleistocene Era pluvial lake, which has subsequently been reduced in size.

Which part of a glacier will see the build-up of ice and snow over the course of a full year?

Zone of Accumulation

Piedmont glacier

a broad lobe that spreads out to flow on an open plain

What depositional feature is visible here?

Delta

Which of the following statements accurately describes what a 100-year flood is?

1% chance of it happening every year.

How many dams, not including the two dams placemarked in the Dams folder, impound the Colorado River between Glen Canyon and Lake Havasu?

2

At which of the following locations is deposition occurring?

B, D

Flood-control dams

Built to store floodwater and release it slowly

Zone of erosion

Headwaters Mountains Steep Gradient Small Channel Size Small Volume of water Big Boulders on Bed

Select the TWO names from the list below that are considered the two main types of glaciers:

Ice sheets alpine or valley

Which of the following are part of the bed load?

Sand and gravel

The figure below shows a mountain stream that has been dammed. The dam has created an artificial lake into which the mountain stream now flows. Label the diagram to specify which points are below base level, at base level, and above base level for the stream flowing into the artificial lake.

(left to right) below ultimate base level ultimate base level local base level above local base level

Direction and location of stream-flow controlled primarily by slope

-Peaks surrounded by valleys -Solid igneous bedrock of uniform composition and slope -Layers of solid sedimentary, similar rock

Has steep gradient, high channel roughness

Headwaters

Analyze the graph and sort the following characteristics as those which appear at the headwaters and mouth of the stream.

Headwaters -Channel roughness is high -Channel size is smaller Mouth -Slope is lower -Discharge is higher -Flow velocity is more

In general, how do the channel width, channel depth, flow velocity, and discharge change between the headwaters and the mouth of the stream?

The channel width, channel depth, flow velocity, and discharge all increase as the stream approaches the mouth.

What is base level?

The downward limit of erosion.

Part E False

The second photo shows the cross-profile of the fan outlined in yellow. The basin center and the alluvial fan are both made up of fine-grained sediments.

Part E True

The second photo shows the long profile of the fan. The toe of the fan can be seen in both photos.

What is a stream's longitudinal profile?

a cross-sectional view of a stream from the headwaters to its mouth

What factors would decrease flow velocity?

a decrease in gradient of the stream a decrease in stream discharge having a rough channel

At approximately what velocity will a 0.1 mm sediment particle begin moving in the stream?

0.6 cm/sec

Part D - Grain Size Changes on a FanIn the photo below, choose the photo showing the most likely grain size that you would find at the apex, middle, and toe of an alluvial fan.Drag the appropriate photos to their respective targets. All photos will be used.

A. big rocks B. medium rocks C. fine rocks

Three Google Earth images from the northern part of Death Valley are shown below. Each photo shows highlighted features associated with alluvial fans or surrounding landforms. Part C - A Bird's-Eye View of Death Valley, CaliforniaThree Google Earth images from the northern part of Death Valley are shown below. Each photo shows highlighted features associated with alluvial fans or surrounding landforms.

A. distributary channels B. fan apex C. basin center dune field D. toe of a fan E. long fan profile

Which of the placemarks in the Cedar Rapids folder is located outside the 100-year floodplain zone?

C

What is the difference between capacity and competence?

Capacity is the maximum load of solid particles a stream can transport per unit of time, whereas competence is a measure of a stream's ability to transport particles based on size rather than quantity.

A river with a well develop _____ had a flat low lying channels and experiences flooding during periods of high discard

Floodplain

Which of the following locations is a likely place to find a braided stream?

Flowing from the terminus of a glacier

Delta

Form where streams enter large lakes or oceans

Levee

Formed by floodwaters on either side of a stream

Alluvial Fan

Formed by mountain streams emerging onto a flat plain

Which of the following statements is true?

Low gradient is associated with deposition.

Which of the following scenarios represents the best nonstructural approach to flood control?

Managing a floodplain to limit development in sensitive areas

What kind of stream channel is visible here?

Meandering channel

Zone of Deposition

Mouth Large Channel Size Large Volume of Water Gently Slope

Why do farmers apply nitrogen to their fields in the spring and fall?

Nitrogen provides nutrients to the plants for the coming growing season.

How many stream terraces can exist along a single valley?

No limit exists. Stream terraces will keep forming as long as lateral erosion and downcutting continue.

Which of the following particle sizes is most likely to make up a stream's suspended load?

Silt

Which of the following sketches best represents the longitudinal profile of the slope of a streambed?

Slope decreases downstream

Bar

Small deposits that form in the stream channel

Affected by both flow velocity and settling velocity of steam

Suspended Load

Arrange the labeled locations in the following figure based on stream power. Pay attention to the stream gradient of the three locations by using the elevation profile as a guide.

c, b, a