Erosion & Deposition

DEFINITIONS Erosion - Brainstorm: 1) What is it? 2) What can cause it? 3) How does erosion change the surface of the Earth? - Possible Types: Have students discuss these questions as a class. Then have the students choose an appropriate definition to write. (Guide them to correct definition). The write down some of the possible causes that the students think cause weathering.

EROSION Erosion= movement of sediment by ice, wind, water, or gravity Is erosion constructive, destructive, or both? Why?

Erosion is a destructive force. Erosion wears down Earth’s surface gully river valley

CAUSES of EROSION Ice (Glaciers) Glaciers carry materials along as they move forward

ICE EROSION EFFECTS ICE a. “U” shaped Valley b. Flat Plains

CAUSES of EROSION WIND carries (blows) sediments and soil from one place to another

WIND EROSION EFFECTS WIND a.Reshaped surfaces b.Sand storms c.Dust storms

EROSION EFFECTS

CAUSES of EROSION Moving water in streams & rivers carries sediments along as it moves down stream. The faster the water, the more and the heavier material it can carry

WATER EROSION EFFECTS KARST Landscape Karst is an area of land that is mostly made of limestone & because of this usually has a lot of caves & sinkholes.

WATER EROSION EFFECTS caves

WATER EROSION EFFECTS Caves are formed when rock is chemically dissolved and carried away by groundwater or underground rivers leaving “holes” in the rock.

WATER EROSION EFFECTS sinkholes Sinkholes form when the rock underneath the soil, is eroded away & the and above sinks because it is no longer supported sinkholes

WATER EROSION EFFECTS River valleys & canyons are formed when fast moving rivers erode the land over long periods of time.

EROSION EFFECTS Floodplains are formed over time when a river or stream overflows its regular banks and erodes the land around it.

CAUSES of EROSION Gravity Causes water and glaciers to move downhill particles (sediments, dust, soil, etc.) carried by water and wind to settle on bottom on stream or the ground

GRAVITY EROSION EFFECTS Mass Movement Mudflows Landslides

DEFINITIONS Deposition - Brainstorm: 1) What is it? 2) How can deposition change the surface of the Earth? - Have students discuss these questions as a class. Then have the students choose an appropriate definition to write. (Guide them to correct definition). The write down some of the possible causes that the students think cause weathering.

Deposition Deposition= build up of land through the dropping off of sediments that are being carried by ice, wind, water or gravity Is deposition constructive, destructive, or both? Why?

Deposition Deposition is constructive because it builds up Earth’s surface

DEPOSITION NONLIVING CAUSES ICE Glaciers deposit sediments as they begin to melt (recede)

DEPOSITION EFFECTS ICE -moraines -lakes -hills

FORCES OF EROSION & DEPOSITION WIND When the wind slows down, the sediments are deposited The heaviest sediments are dropped first

Deposition Effects Wind Sand dunes

DEPOSITION NONLIVING CAUSES WATER -When the water slows down, the heaviest sediments are deposited first Older rivers have curves called meanders.

Canarvon Gascoyne Delta Shark Bay W Australia

DEPOSITION EFFECTS WATER sandbar delta beach

DEPOSITION EFFECTS FLOODPLAINS

DEPOSITION EFFECTS WATER stalagmites, & stalactites (ground) (ceiling)

Constructive and Destructive Forces Review Forces that tear down/wear away Earth’s surface Examples: Weathering Erosion Constructive Forces that build up Earth’s surface Example: Deposition