Weathering TypesWeathering And And Erosion Erosion &Deposition
Breaking it Down the Real Earth surface! How does Erosion and Deposition Change theSurface of the Earth?S6E5. Students will investigate the scientific viewof how the earth’s surface is formed.i. Explain the effects of human activity on theerosion of the earth’s surface.S6CS10. Students will enhance reading in all curriculum areas by:c. Building vocabulary knowledgeDemonstrate 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 windchange 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 ofThere are many different types of Physical / Weathering mechanical weathering . Here are a few AGENTS:•Root Pry • Wind Abrasion• Exfoliation • Frost action• Frost Action
Root plant action PryThe tree is growing in the rock and soon the rockwill break apart because of the tree roots.
This is a picture of the Half Dome. The rock ispeeling away from the mountain inlayers 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 weathering and AGENTS: Living Organisms• Acids in Groundwater • Karst Topography
This rock is red because of the oxidation of iron in the sediment when the rock was being formed.
1908 to 1969Acid rain has eaten away this limestone statue. Acid Rain
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
There are 4 factors that affect the rate of weathering:1. Surface Area (exposure) - Exposing more surface area willincrease the rate of weathering. 2. Particle Size – Larger particles weather slower and smaller particles weather at a faster rate.3. Chemical Composition (what a rock is made of) – Certain rocksand minerals are naturally weaker than others, while others aremore resistant (stronger).4. Climate – Warmer, moister climates have the most weathering.Heat & Water speed up all chemical reactions. This is the mostimportant factor in weathering. 17
Erosion is the process by whichsoil and rock are moved fromone location to another on thesurface by natural processessuch as wind or water flow, andthen transported and depositedin other locations.
Erosion There are many kinds of Erosion. Here are a few AGENTS:• Wave Action • Avalanche •Creep• Running Water •Glaciers • Rock Fall• Landslides • Slump • 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 Earths 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 Earths surface.
Wave action is when waves hit the rocks and pieces of rock break off.
In this picture the running water eroded the sidesof 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
Mass Movements • Landslides, mudslides, slump and creepSlower Faster landslide clip.mpeg
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.
LANDSLIDE MUDFLOW1 2 What type of mass movement is each picture? http://classes.colgate.edu/dkeller/geol101/massw/mass.htm SLUMP CREEP3 4
Ice ErosionGlaciers wear down the landscape; by picking upand carrying debris that moves across the landalong with the ice.Glaciers can pick up and carry sediment thatranges in size from sand grains to boulders biggerthan houses.Moving like a conveyor belt or a bulldozer, a singleglacier can move millions of tons of material!How much erosion takes place is determined bythe: •**Sum (Glaciers are massive!) •Slope •Speed
This is a picture of a glacier which carves out a U-shaped valley where it flowsdragging rocks and boulders along the way.
You can identify which agent of erosion transported each sediment by looking ata few characteristics:Running Water – sediments that have been transported throughrunning water appear rounded and smooth and are deposited insorted piles.Glaciers – sediments that have been transported by glaciers appearscratched, grooved, and are deposited in completely unsortedpiles, because they were dropped during melting. Also, boulderscan only be transported by glaciers.Wind - sediments that have been transported by wind are appearpitted (random holes) and frosted (glazed look) and are depositedin sorted piles. Only very small particles can be transported bywind.Gravity – sediments that are transported by gravity are found inpiles at the bottom of cliffs or steep slopes. They appear angularand unsorted. Mrs. Degl 34
Factors that influence erosional rates (speed) in runningwater and glacial ice:1. Slope (gradient) of the land – as slope increases, thewater velocity increases, the particle size that the watercan carry also increases, therefore the amount of erosionincreases.2. Volume (size of the water or glacier) – as the volume ofthe 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 travelingfaster around the outside of turns therefore that iswhere more erosion occurs. Water is traveling slower onthe inside of turns; therefore deposition occurs on theinside. Mrs. Degl 35
Deposition Rock particles that are picked up and transported during erosion will ultimately be deposited somewhere elseDeposition 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
Delta – a fan shaped deposit that forms at the mouth of ariver/stream when it enters a larger body of water. This is seenunder the water. The particles are horizontally sorted. Mrs. Degl 39
Alluvial Fan - a fan shaped deposit of sediments that formswhen a stream/river flows out of a mountain on to flat, dry plains.These are not under water and are very visible. This onlyhappens on the land. You can call it a “land delta”. Mrs. Degl 40
Canyons Canyons are large valleyscreated by a river or stream.
MeanderMeandering streams wander side to side as they constantly seek out the lowest elevation.This constant motion creates a series of S-shaped “loops”.
Meandering (Curving) River/Stream Deposition Erosion happens happens on the on the inside of outside of turns. turns.Sedimentsare Straight Flowing River/Stream Runningtravelingthe fastest Waterin thecenterdirectlybelow thesurface. Mrs. Degl 43
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.
http://www.school-portal.co.uk/GroupDownloadFile.asp?file=21604 5 1 2 3 2 SANDBAR DELTA BEACH 1 4 4 6 4 ALLUVIAL FANWhat did water create in each of these pictures?
Humans areHow does this affect us? constantly influencing the nature of our landscapes. HOUSES, ROADS, BUILDINGS, DEVELOPMENTS, CANALS, etc., all change the shape and appearance of the land.
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 48 sides.
Summary please pick ONE• Use at least two facts from your notesto 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? 49