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WEATHERING AND EROSION Rock Cycle WEATHERING I. Weathering - The breakdown of rock due to exposure to the atmosphere, weather, plants, and animals.

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Presentation on theme: "WEATHERING AND EROSION Rock Cycle WEATHERING I. Weathering - The breakdown of rock due to exposure to the atmosphere, weather, plants, and animals."— Presentation transcript:

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2 WEATHERING AND EROSION

3 Rock Cycle

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5 WEATHERING I. Weathering - The breakdown of rock due to exposure to the atmosphere, weather, plants, and animals. A. Mechanical Weathering (Physical Weathering) - Rock is split or broken into smaller material without changing its composition. B. Chemical Weathering – Process by which rocks break down as a result of chemical reactions.

6 Mechanical (Physical)Weathering §1. Ice wedging (Porus, rocks with cracks (ice heaving/Frost Action) §2. Wetting and drying (for clay containing rocks) §3. Plants (lichens, mosses, shrubs, trees) §4. Exfoliation (the peeling away of surface layers) due to the relief of pressure from rocks above it. §5, Expansion / Contraction (Temperature) §6. Abrasion- process of breaking down by means of friction

7 ABRASION

8 ABRASION BY WATER

9 Abrasion – wears down or rounds

10 ABRASION BY WIND

11 MECHANICAL WEATHERING Was once solid rock

12 MECHANICAL WEATHERING

13 ICE WEDGING

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17 PLANTS

18 EXFOLIATION

19 Exfoliation – causes rock to sheet or flake off

20 Barrel cactus – breaking through rock to grow

21 EXFOLIATION

22 WEATHERING B. Chemical Weathering - Break down of rocks when the rock minerals are changed to different substances.

23 Chemical Weathering §1. Hydrolysis - chemical reaction with water and other substances (feldspar, hornblende, augite) these combine to form clay. §2. Oxidation - chemical reaction with oxygen and other substances. (Iron bearing substances), (red soil in Carolina & Virgina) §3. Carbonic acid/Carbonation - Carbon dioxide dissolves in H2O to form carbonic acid. (found in soda), P,Na,Mg and Ca (forms caves) §4. Acid Rain - sulfur from cars and coal/oil plants §5. Plants/Animals (Lichens) - produce rock dissolving acids

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25 CHEMICAL WEATHERING

26 Carbonation Clip

27 Details worn away by chemical weathering

28 Acid Rain

29 Oxidation

30 Hydrolysis -Reaction of any substance with water

31 Chemical Weathering- Water molecules "pull" apart a mineral (dissolve it)

32 Plants can grow on rocks and produce weak acids that can break down rock.

33 Organic Weathering Lichen breaking down rock

34 Bird dropping weathering §

35 RATES OF WEATHERING II. Rates of Weathering 1. The rocks themselves - Igneous and metamorphic most resistant, sedimentary least resistant because of pores. 2. Surface Area – More surface area = faster weathering 3. Climate - Warm and wet = chemical weathering Cold and Dry = mechanical weathering 4. Topography

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43 com/search/assetDetail.cfm?guidAss etID=6B1E329E-5A77-4B36-BFA9- 1D307F75441C

44 Weathering §Get on the online book and go to chapter 14. §Select the visual concepts and watch the clips on physical and chemical weathering.

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46 EROSION IV. EROSION- The breakup and removal of rock by moving natural agents (gravity, glaciers, wind, water) A. Water Erosion 1. Rain a. Sheet wash - thin sheets of soil removed prevent by - grass, continued plowing, crop rotation, strip crop, terraces b.Gullying - valleys in sloped land - farms 2. Running water - most effective agent of erosion a. stream, river, creek b. Stream abrasion - grinding away of rock from bed or bank. c. The faster the river moves = more stuff it can carry

47 EROSION B. Wind Erosion - just as water; only less powerful 1. Abrasion - wearing down of particles 2.Deflation - removal of loose particles by wind - the most important effect by wind 3. Dunes - sand piled up, moved by wind C. Glaciers – most powerful agent of erosion

48 Gullying

49 DEFLATION

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52 DUNES

53 Arches National Park Wind abrasion

54 EROSION IV. EROSION- The breakup and removal of rock by moving natural agents (rivers, glaciers, wind, water) A. Mass movements - Earth material down a slope caused by gravity. 1. Creep - Very, Very slow down slope movement of soil. (water in soil adds to it) a. Talus - Loose rock fragments at base of cliffs 2. Landslides - sudden movement of bedrock or loose rocks down a cliff. 3. Slumps - small landslides on hills 4. Mudflow - fast movement of water saturated clay and silt. 5. Avalanche

55 TALUS

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58 Landslide – mass movement

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61 LANDSLIDE

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64 Landslide – mass movement

65 CREEP

66 Creep

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69 SLUMPS

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71 SLUMP

72 MUDFLOW

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82 The Colorado River weather and eroded way for 1,000s of years

83 Brought to us by the Colorado River

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