erosion & weathering change
DESCRIPTION
S6E5. Students will investigate the scientific view of how the earth’s surface is formed. Gathering facts over erosion, weathering & depositionTRANSCRIPT
WeatheringWeathering
And And
ErosionErosion
Weathering Types
And
Erosion
&
Deposition
Breaking it Down the Real Earth surface! How does Erosion and Deposition Change the Surface of the Earth?
S6E5. Students will investigate the scientific view of how the earth’s surface is formed. i. Explain the effects of human activity on the erosion of the earth’s surface. S6CS10. Students will enhance reading in all curriculum areas by: c. Building vocabulary knowledge Demonstrate an understanding of contextual vocabulary in various subjects. Use content vocabulary in writing and speaking. Explore understanding of new words found in subject area texts.
Essential Question(s): How does water and wind change the surface of the earth?
Weathering• Weathering is simply the chemical and/or
physical breakdown of a rock material--weathering involves specific processes acting on rock materials at or near the surface of the Earth
The Different Types of WeatheringThere are many different types of Physical /
mechanical weathering.
Here are a few AGENTS:
•Root Pry
• Exfoliation
• Frost Action
• Wind Abrasion
• Frost action
Root plant action Pry
The tree is growing in the rock and soon the rock will break apart because of the tree
roots.
This is a picture of the Half
Dome. The rock is peeling away
from the mountain in
layers just like an onion. This is exfoliation.
Frost Action or ice wedging slowly breaks up this sedimentary rock into unusual
shapes.
These rocks have been blasted by wind and sand causing them to
become rounded.
WIND ABRASION
Chemical weatheringand AGENTS:
• Acids in Groundwater• Karst
Topography
Living Organisms
This rock is red because of the oxidation of iron in the sediment when
the rock was being formed.
Acid Rain
1908 to 1969
Acid rain has eaten away this limestone statue.
Karst Topography
• A type of landscape in rainy regions where there is limestone near the surface, characterized by caves, sinkholes, and disappearing streams.
• Created by chemical weathering of limestone
Features of Karst: Sinkholes
Features of Karst: Caves
Living Organisms
• Lichens that grow on rocks produce weak acids that chemically weather rock
Chemical
Weathering
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2. Particle Size – Larger particles weather slower and smaller particles weather at a faster rate.
There are 4 factors that affect the rate of weathering:1. Surface Area (exposure) - Exposing more surface area will increase the rate of weathering.
3. Chemical Composition (what a rock is made of) – Certain rocks and minerals are naturally weaker than others, while others are more resistant (stronger). 4. Climate – Warmer, moister climates have the most weathering. Heat & Water speed up all chemical reactions. This is the most important factor in weathering.
Erosion is the process by which soil and rock are moved from one location to another on the surface by natural processes such as wind or water flow, and then transported and deposited in other locations.
Erosion
There are many kinds of Erosion.
Here are a few AGENTS:
• Wave Action
• Running Water
• Landslides
• Avalanche
•Glaciers
• Slump
•Creep
• Rock Fall
• Mud Flow
What is Erosion? Erosion is defined as removal of rocks and
soil by wind, water, ice and gravity. Wind, water, ice and gravity are also known
as the agents of erosion and through erosion, a river creates valleys, waterfalls, flood plains, meanders, and oxbow lakes
Water Erosion
Water running downhill is the major agent of erosion that has shaped Earth's land surface. The force of a falling raindrop can loosen and pick up soil particles. As water moves over land, it carries these particles with it. This moving water is called runoff, which is water that moves over Earth's surface.
Wave action is when waves hit the rocks and pieces of rock break off.
In this picture the running water eroded the sides of this canyon and created the V-
shaped valleys.
Gravity Erosion-Rock Fall
Gravity Erosion is better known as Mass Movement and is defined as the transfer of
rock and soil down slope by direct
action of gravity without a flowing medium (such as water or ice). Some of the
best examples of Mass Movement are: Creep
Rock fall Slump Landslides Avalanches
Mass Movements
• Landslides, mudslides, slump and creep
landslide clip.mpeg
Slower Faster
This is a picture of a landslide. A type of mass
wasting.
In this picture the land has slumped
into the road below.
This is a diagram of creep. The hillside slowly slips over many
years from temperature or water.
This is a picture of an avalanche. It is similar to a landslide with ice and snow
instead of rock.
What type of mass movement is each picture?http://classes.colgate.edu/dkeller/geol101/massw/mass.htm
LANDSLIDE MUDFLOW
SLUMP CREEP
1 2
3 4
Ice ErosionGlaciers wear down the landscape; by picking up and carrying debris that moves across the land along with the ice.
Glaciers can pick up and carry sediment that ranges in size from sand grains to boulders bigger than houses.
Moving like a conveyor belt or a bulldozer, a single glacier can move millions of tons of material!
How much erosion takes place is determined by the:
•**Sum (Glaciers are massive!)•Slope•Speed•Surface
IceIce (glaciers) carry sediment.
This is a picture of a glacier which carves out a U-shaped valley where it
flows dragging rocks and boulders along the way.
Mrs. Degl 34
You can identify which agent of erosion transported each sediment by looking at
a few characteristics:Running Water – sediments that have been transported through running water appear rounded and smooth and are deposited in sorted piles.
Glaciers – sediments that have been transported by glaciers appear scratched, grooved, and are deposited in completely unsorted piles, because they were dropped during melting. Also, boulders can only be transported by glaciers.
Wind - sediments that have been transported by wind are appear pitted (random holes) and frosted (glazed look) and are deposited in sorted piles. Only very small particles can be transported by wind.
Gravity – sediments that are transported by gravity are found in piles at the bottom of cliffs or steep slopes. They appear angular and unsorted.
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Factors that influence erosional rates (speed) in running water and glacial ice:
1. Slope (gradient) of the land – as slope increases, the water velocity increases, the particle size that the water can carry also increases, therefore the amount of erosion increases.2. Volume (size of the water or glacier) – as the volume of the water or glacier increases, their velocities increase, the particle size that they can carry also increases, therefore the amount of erosion increases.3. Position within the running water – Water is traveling faster around the outside of turns therefore that is where more erosion occurs. Water is traveling slower on the inside of turns; therefore deposition occurs on the inside.
Deposition
Rock particles that are picked up and transported during erosion will ultimately be deposited
somewhere else
Deposition is the process by which sediments (small particles of rock) are laid down in new locations. • Together, Erosion and Deposition build new
landforms. • Deltas
• Canyons• Meanders
• Floodplains
Water Deposition Deltas – slow river current drops sediment in fan-shaped
pattern at end of river
Sand Bars – offshore deposit of sand, gravel, or shell material
Alluvial Fans
Beaches – deposited sand
Delta
• Where rivers meet the ocean is called the mouth of the river. Soil and dirt carried by these rivers is deposited at the mouth, and new land is formed. The new, soil-rich land is known as a Delta
Mrs. Degl 39
Delta – a fan shaped deposit that forms at the mouth of a river/stream when it enters a larger body of water. This is seen under the water. The particles are horizontally sorted.
Mrs. Degl 40
Alluvial Fan - a fan shaped deposit of sediments that forms when a stream/river flows out of a mountain on to flat, dry plains. These are not under water and are very visible. This only happens on the land. You can call it a “land delta”.
Canyons
Canyons are large valleys created by a river or stream.
Meander
Meandering streams wander side to side as they constantly seek out the lowest elevation.
This constant motion creates a series of S-shaped “loops”.
Mrs. Degl 43
Meandering (Curving) River/Stream
Straight Flowing River/StreamSediments are traveling the fastest in the center directly below the surface.
Erosion happens on the outside of turns.
Deposition happens on the inside of turns.
Running Water
Mrs. Degl 44
Floodplains
• These are low-lying areas along the sides of a river channel that have regular times of heavy wate rflow to cause the river to spill over and flood the land.
What did water create in each of these pictures?
DELTA SANDBAR
ALLUVIAL FAN
http://www.school-portal.co.uk/GroupDownloadFile.asp?file=21604
1
2
4 4 6
1 2
4
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BEACH
How does this affect us?Humans are constantly
influencing the nature of our landscapes.
HOUSES, ROADS, BUILDINGS,
DEVELOPMENTS, CANALS, etc., all
change the shape and
appearance of the land.
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There are 5 ways that man can cause erosion:
1. Forestry – all vegetation of removed, and without roots, the soil will erode away.
2. Strip Mining –removing rock cover to get to the resources below, this causes the loose sediments to erode away.
3. Construction – the clearing of land to build buildings/houses also causes all loose soil to erode away.
4. Improper Farming – not plowing the land at right angles to slopes causes soil to erode away.
5. Salting Highways – the salt is washed off the road to the sides, where it prevents vegetative growth along the sides.
Summary please pick ONE
• Use at least two facts from your notes
to explain the question below.• How does Erosion and Deposition
Change the Surface of the Earth? OR• How does water and wind change
the surface of the earth?
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