Weathering 08 Smart

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Weathering, Erosion and Deposition

Weathering ______________________________________________________________________________

Types of Weathering

A. ________________ weathering

__________________________________________________________________________________

_

1._______________________

as rocks are heated by the Sun the ____________.

When the temperature falls the outside

layers cool and ____________.

The cycle of heating and cooling cause

the surface of the rock to break off in

slabs or layers. This process is called

___________________________.

Any process that causes rocks to break into smaller pieces without changing chemically

the physical and chemical breakdown of rocks into smaller particles called sediment

PHYSICAL

Temperature Change

expand

contract

exfoliation



2. ______________________________ also called

_____________________.

This occurs when water seeps into the cracks ib a rock.

When water freezes it ____________. The cycle of freezing

and melting causes rocks to break apart. This same process

happens to our roads and creates ____________ in the road.

3. _____________________________ This process occurs when

trees and shrubs can grow through cracks in rocks. Their roots

wedge into crevices. Even moss and lichen wedge their hair-like

roots between the grains that make-up rocks.

4. _____________________________ sediments carried by streams and

wind blown sand causes particles to collide into each other and the

surrounding rock.

expands

Abrasion

Organic Activity

potholes

Frost Wedging

Frost Action

http://www3.interscience.wiley.com:8100/legacy/college/strahler/0471238007/animations/ch15_animations/animation2.html

http://www.classzone.com/books/earth_science/terc/content/visualizations/es1201/es1201page01.cfm?chapter_no=visualization



B. ____________________________ weathering

_______________________________________________________________________________________

_________________________________________

1. ________________________ occurs when carbon dioxide in the atmosphere dissolves in the droplets of

water that make up clouds. This forms a weak carbonic acid. Carbonic acid reacts with certain rocks and

minerals that include; ________________________________________________________________

________________ bedrock

Carbonic Acid seeps into the

limestone bedrock through cracks. Thiswater dissolves the limestone rock.

A cavern forms that includes the

following features.

___________________________

Any process that causes rocks to breakdown by chemical action and results in a change in

the mineral composition

Calcite, limestone, marble and chalk

Carbonation

Chemical

columnsstalagmites

stalactitessinkholes

Limestone




2. _______________ occurs when water

dissolves certain minerals in a rock.

For example, granite is very stable in

cool, dry climates but in moist climates

rainfall dissolves much of the mineral

feldspar. The feldspar becomes clay

which is too weak to keep the rock from breaking apart. The mineral quartz remains behind as sand.

9. ________________ occurs when oxygen in the atmosphere combines with certain minerals in the rock.

For example when oxygen combines with iron minerals, iron oxide (rust) forms. The chemical change of

the mineral weakens the rock and the rock crumbles.

10. ________________ produce weak acids that can dissolve certain minerals in a rock, weakening the rock.

11. __________________________ Gases produced by humans can dissolve in the water droplets of a

cloud to produce ________________.

These acids include: H2SO4 __________________

HNO3 ___________________

Hydration

Oxidation

Plants acids

sulfuric acid

Man-created acids

nitric acid

acid rain



Weathering Rates

A. ____________________ is the major factor that affects the rate of weathering.

1. Temperature:

a. In warm climates

__________________ is the

dominant type of weathering.

b. In cold climates

__________________ is the

dominant type of weathering.

2. Precipitation:

a. As precipitation increases, the amount (or rate) of weathering by frost action will

_______________________.

b. As precipitation increases, the amount (or rate) of chemical weathering will

__________________________.

3. Chemical weathering is most rapid in ________________________, _______________________

climates.

4. Due to climate and different weathering processes, landscapes develop differently.

Climate

chemical action

frost action

increases

increases

moist

warm



B. ____________________________________ causes differential weathering. Differential

weathering is the process by which softer, less weather-resistant rocks wear away, leaving

harder, more weather-resistant rocks behind.

sandstone shale

limestone dolostone

Which rock type is most resistant to weathering? __________________________

Which rock type is least resistant to weathering? __________________________

H. _________________________ Weathering takes place on the outside surface of rocks. So

the more __________________ that is exposed to weathering, the faster the rock will be

broken down.

As a rock breaks into smaller pieces, the ________________ area increases, so the rate of

weathering _____________.

Different types of rocks

dolostone

shale

Particle Size

surface area

surface

increases



Name of Sediment Size

25.6 and larger

25.6-6.4

6.4-2.0

0.2-0.006

0.006-0.0004

0.0004- and smaller

boulders

cobbles

pebbles

sand

clay

silt

Products of Weathering



Soil

1. Soil is a combination of ________________ and ___________________.

2. ________________ is decayed plant and animal material found in soil. Soil that contains 20 to 30%

humus is considered a rich soil for plant growth.

3. Soil development

4. Soil layers – the SOIL PROFILE

1. ______________ or _______________

is the top layer of soil that contains more

humus than the layers below.

2. ______________ or _______________

consist of clays and dissolved minerals

that have been washed down from

above. Contains less humus.

3. __________ consists of weathered rock

fragments, usually from the parent rock.

4. ________________ is the layered rock

beneath the soil. Frequently it is the

parent rock of the soil above.

weathered rock organic material

Humus

B horizonSubsoil

C horizon

Bedrock

A horizonTopsoil



1. Residual Vs Transported Soil

If the bedrock matches the rock fragments of the C horizon, the soil is most likely

_____________________________. If it does not the soil is most likely _____________________________.

residual

transported



Erosion and Deposition

A. Erosion is ___________________________________________________________________________

1. Am agent of erosion is a material or force that moves sediments from one place to another place.

2. Agents of erosion include: __________________, __________________, __________________ and

____________________.

B. Deposition is ________________________________________________________________________

1. Deposition occurs when the velocity (speed) of running water or the wind ____________________

and/or when the discharge (volume of water) ____________________.

2. Factors that affect the deposition of sediment:

a. Size __________________________________________________________________________

b. Density ________________________________________________________________________

the process by which weathered sediments are carried or transported.

running water wind glaciers

waves

the process by which sediment is dropped or settles

The size of sediment increases, the rate of deposition increases.

decreases

decreases

As density of increases, the rate (speed) of deposition increases

Time for

Deposition

Size of Sediment

Rate of

Deposition

Size of Sediment

Time for

Deposition

Density of Sediment

Rate of

Deposition

Density of Sediment




C. Shape - ________________________________________________________________________________

D. Gravity – erosion and deposition

1. Gravity pulls sediments down slopes.

2. The downhill movement of sediments by gravity is called ___________________.

3, Types of mass wasting include: ________________________________

4. Deposition resulting from gravity

As the shape becomes more spherical, the rate of deposition of the sediment increases.

Talus Pile/ Slope

Time for

Deposition

Flat------------SphericalShape of Sediments

Rate of

Deposition

Flat------------SphericalShape of Sediments

mass wasting

landslides and mudslides



5. Gravity is the underlying force behind all erosion; it may act alone or with a transporting agent.

a. _____________ causes water to flow downhill.

b. _____________ causes glaciers to flow down a valley or spread outward.

c. _____________ causes winds by pulling heavier (more dense) cold air down beneath lighter (less

dense) warm air.

D. Wind – erosion and deposition

1. The amount of erosion caused by the wind depends on:

a. The __________________ of sediments being carried.

b. The __________________ of which the wind is blowing.

c. The __________________ that the wind continues to blow.

2.

3. Deposition by wind

__________________

WIND

Gravity

Gravity

Gravity

Size

Speed

Time

Well sorted



E. Running Water – erosion

1. Running water is the ______________________________________________.

2.

3. When rain falls onto the surface of Earth several things can happen to the water:

a. ___________________________________________________________

b. ___________________________________________________________

c. ___________________________________________________________

d. ___________________________________________________________

4. The volume (amount) of water in a stream is called the stream’s ______________________.

Factors affecting a stream’s volume are:

a. Season – spring vs. fall; usually greater in the _____________________.

b. Climate – arid vs. humid; usually greater in ________________________.

c. Weather – daily changes in precipitation affect the volume of a stream.

d. Ground/ Soil – saturated or non-saturated; greater when soil is _____________________.

dominant form of erosion

runoff

infiltrate / sink into ground

evaporate

accumulate in snow and stored in ponds

discharge

spring

humid climates

saturated



Ontario-St Lawrence

Susquehanna-Chesapeake

St Lawrence

Mohawk-Hudson

Champlain-St Lawrence

Long Island Sound

Delaware

Allegheny-Ohio

Erie- St Lawrence

A. Drainage basin - __________________________________________________________

________________________________________________________________________

tributary - ________________________________________________________________

(watershed) the area of land drained by a river system - the

main river and all of its tributaries

A stream that flows into a larger stream or other body of water

St. Lawrence Map





5. Stream factors that cause erosion:

a. _____________ - ________________________________________________

b. ______________ - _______________________________________________

c.

6. Factors that affect stream velocity:

a. _____________ - ________________________________________________

b. _____________ - ________________________________________________

c. Channel - the path the stream follows. When a stream flows through its channel its speed will change due

to the curvature of the channel.

The bends in a stream’s channel are called _______________________.

as velocity increases; erosion increasesVelocity

Volume as volume increases; erosion increases

S t r e a m

Erosion

S t r e a m

Erosion

V e l o c i t y

V o l u m e

Gradient as gradient increases; velocity increases

Volume

meanders

as volume increases; velocity increases



At the outside of the curve, the stream velocity ______________ therefore, ________________ occurs.

At the inside of the curve the stream velocity ____________ therefore, ________________ occurs.

Key:

= deposited stream

sediment

X = location of maximum

velocity

X

X

X

X

X

X

X

X

increases erosion

decreases deposition



7. Stream Load

a. ___________________ - minerals dissolved in the water

b. ___________________ - small particles carried within the water

c ___________________ - larger particles rolling and bouncing along the bottom

8. Particle Size vs. Stream Velocity

What is the largest size sediment that can be transported by a stream in which the water velocity is:

a. 50cm/sec _________________________

b. 150 cm/sec _______________________

c. 250 cm/sec ________________________

Solution

Suspension

Saltation

PebblesPebbles

Cobbles



F. Running Water – deposition

1. When a stream enters a body of water. Its speed will ____________, and therefore the ______________

of sediments occurs. A deposit at the mouth of a stream where it enters a large body of water is called a

_____________.

2. A delta is an example of the __________________ deposition of sediments in water.

___________________ sediment

decrease deposition

delta

horizontal

sorted





3. Stream deposition on land can also occur. This deposit is called an ________________.

5. Equilibrium: Erosion = Deposition

Map View

Profile View

erosion

deposition

equilibrium

alluvial fan



6. Formation of an Oxbow Lake – the work of erosion and deposition

Deposition

Levee

Flood Plain

Oxbow Lake

Erosion



G. Glaciers – erosion and deposition

1. A glacier is _____________________________________________

2. Types of Glaciers

a. ___________________ glaciers form in mountain valleys at high elevations.

examples: _________________

_________________

_________________

b. ____________________ glaciers form over vast areas of land.

examples:

______________________

___________________________

a large mass of moving ice and snow.

Alpine

Alps

Andes

Himalayas

Continental

Greenland

Antarctica

1 Valley Glaciers and Erosion



1. Valley Glaciers and Erosion

a. Movement of a valley glacier – the center moves ______________________ than the sides.

1. ________________________

moraine

2. _________________________

moraine

3. _________________________

moraine

b. Moraine - ________________________________________________________

1. _____________ moraine – unsorted rock on the glacier along the valleywalls.

2. _____________ moraine – unsorted rock on the glacier in the central region

resulting from the merging of two smaller valley glaciers.

3. ____________ moraine – unsorted rock trapped at the bottom of the glacier.

faster

lateral

medial

ground

unsorted rock material carried and deposited by a glacier

Lateral

Medial

Ground



2. ______________________ moraine – unsorted rock trapped at the leading edge or “end” of the

glacier

C. Glacial Valleys

Terminal

4 Ice Age Continental Glaciers



4. Ice Age Continental Glaciers

In the geologic past, a much colder climate resulted in ice sheets covering much of Earth’s surface.

There is evidence of at least _____ major ice ages during the last 2 million years.

a. The time period between ice ages is called the

________________________.

b. The most recent ice age ended about ____________ years ago.11,000

4

Interglacial period



1. Landscape Feature of Continental Glaciers

1. ____________________ - scratches or gouges cut into bedrock by process of glacial

abrasion.

2. ____________________ - an oval-shaped hill of a glacial moraine

3. ____________________ - a large boulder deposited by the ice

4. ____________________ - a lake formed when a block of glacial ice melts

5. ____________________ - a stream that is divided into an interlocking system of channels.

7. ____________________ - a ridge-like hill of deposits resulting from a stream flowing under

a glacier

Glacial striations

Drumlin

Glacial erratic

Kettle lake

Braided stream

Esker



Other landscape features from the last Ice Age

a. Niagara Falls



d. Finger Lakes – The map shows the shapes and locations of New York State’s 11Finger Lakes and the locations of some major glacial deposits (moraines) left behind bythe last ice age. The cross section shows surface elevations, valley depths and waterdepths of the Finger Lakes.



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Weathering 08 Smart