Presentation on theme: "AIM: What forces cause erosion?"— Presentation transcript:
1 AIM: What forces cause erosion? Agents of ErosionAIM: What forces cause erosion?
2 Vocabulary Erosion Mass movement Landslide Creep Slump Mudslide AvalancheLiquefactionRetaining WallsSlope
3 1. Erosion Movement of sediments from one location to another. Landforms are created by a combination of weathering and erosion.Often the forces that cause erosion also cause the weathering of the sediment at the same time.
4 2. Gravity a. ***Driving force of all erosion **** b. Causes Mass Movement or Mass Wasting(Ex - Landslides, mudslides, slump and creep)c. Affected by slope, ground cover, water, climateCan be triggered by earthquakesd. Sediments are angular and rough
8 Retaining walls and metal nets help prevent landslides
9 b. Mudslides Downward flow of water, rock and soil After heavy rain when ground is overly saturated, where vegetation has been stripped, and on steep slopesVolcanoes can trigger a meltLiquefaction – when the land becomes fluid and moves
13 2. Wind a. Erodes fine, small, loose, dry material b. Contributes to abrasion (physical weathering)c. Affected by velocity, sediment size, ground cover, waterd. Sediments are angular with frosted or pitted appearancee. Occurs in deserts, arid areas, seashores
24 1) The photograph shows a sand dune that formed in a coastal area 1) The photograph shows a sand dune that formed in a coastal area. This sand dune was most likely formed byA) water flowing from the leftB) water flowing from the rightC) wind blowing from the leftD) wind blowing from the right
25 The picture below shows a geological feature in the Kalahari Desert of southwestern Africa. Which process most likely produced the present appearance of this feature?A) wind erosionB) volcanic eruptionC) earthquake vibrationsD) plate tectonics
26 3. Glacial LandmassesGlacier – a large mass of moving ice, found in areas of - High elevation ( mountaintops) - High latitude ( polar regions)b. Two types:Valley glacier – long and narrow, forms high in the mountainsContinental glacier – ice caps, covers much land, ex – Greenland, Antarctica, Alaska
27 3. Glaciers c. Gravity pulls weight of glacier down mountain d. Glaciers can move cm/daye. Affected by slope, weight, and velocityf. Erodes many sizes - boulders to sandg. Sediments are unsorted (mixed sizes)h. Sediments have sharp angles, irregular shapes,rough, grooves (striations)i. Carve U-shaped valleys
28 Ice ages – when glaciers covered large parts of the Earth’s surface
34 Glacial erosion Plucking – rocks freeze to the glacier and moves it Abrasion – rocks in glacier scratch bedrock causing striations
35 Striations – grooves carved in rock can tell you the way a glacier moved
36 Glacial DepositionWhen sediments are eroded, they must come to rest somewhere. They are deposited in a location that creates a landform.Glaciers deposit sediments, as well as water, wind and gravity.
37 Glacial DepositionTill – the sediment piles that are created by glaciers are unsorted deposits, meaning they have many shapes and sizes of sediments.
38 Glacial DepositionMoraine – till deposited at the edge of a glacier makes a mound