Upload
jeffry-armstrong
View
223
Download
2
Tags:
Embed Size (px)
Citation preview
Erosion and DepositionErosion and Deposition• Erosion – is the
process by which weathered rock and soil particles are moved from one place to another.
• Deposition – Sediments are laid down in a new location.
Five Factors of ErosionFive Factors of Erosion
• Gravity• Wind• Running Water• Glaciers• Waves
GravityGravity
• Mass Wasting- the downhill movement of sediments caused by gravity.
• Landslides• Mudflows
SlumpSlump• A block of Rock or soil moves down a steep
slope with its upper surface tilted backwards as it falls
Slow Mass WastingSlow Mass Wasting
• Earth Flows and Soil creep are two examples of slow mass wasting
Wind ErosionWind Erosion• Deflation – Wind
removes loose materials such as sand, silt and clay
• Abrasion – Sand Blasting
Features formed by Wind ErosionFeatures formed by Wind Erosion• Dunes – Wind blown
sand is deposited near rock and bushes in desert areas
• Loess – Very fertile, light in color, many meters thick consisting of sand and silt
How can you curtail wind erosion?How can you curtail wind erosion?
• Bushes, trees and fences act like barriers to block the wind
Major Cause of ErosionMajor Cause of Erosion• Running Water – Water turns into
runoff as it travels, picking up weathered rock particles and making small grooves in the ground known as Rills. As the Erosional process continues, the grooves become larger and are now called “Gullies.”
Factors that affect RunoffFactors that affect Runoff
• Amount of rainfall
• Plant Growth
• Shape of the Land
Life Cycle of a RiverLife Cycle of a River• Immature River –
Early stages of development
• Mature River – In development for thousands of years
Life Cycle of a RiverLife Cycle of a River
• Meandering – A river begins to curve and wind due to erosional forces
Oxbow LakeOxbow Lake
• Large “U” shaped bends forming small lakes
As a river leaves a mountain and runsout onto a flat plain its speed decreases and its sediments are spread out in a fan like shape called an Alluvial Fan
Delta - large amounts of sediments deposited at the mouth of a river that flow into a lake or ocean
Rivers overflow their banks after heavy periods of rain or thaw And leave fine sediment deposits
Levees are formed from larger particles that settle of the sides of rivers
Glacial Ice erodes away rock as it moves by abrasion and plucking away at the rock beneath it
Rocks and soil that are deposited by the glacier are called “Till”
After a Glacier melts and retreats, it leaves behind till, which forms a ridge called a “Moraine”
An oval shaped mound of Till is called a “Drumlin”
Melt water deposits are left by a Valley Glacier stops moving
Out wash Plains are fan shaped and formed In front of a Terminal Moraine
As a Iceberg melts it leaves its deposits on the Ocean Floor
Kettle Lakes (Great Lakes) form in two ways:1) Glacial Till deposits form in river channels causing water to form lakes2) Blocks of ice melt away leaving sediments behind and a depression forms after the ice melts