480 likes | 694 Views
EARTH SCIENCE CHAPTER 7. WEATHERING EROSION SOIL FORMATION. Appalachians Today. Appalachians 400 mya. 7.1 Weathering. What is it? 2 types. Cleopatra's Needle. before. after. Mechanical (physical)—rocks are broken down into smaller pieces Gravity— Temperature— Ex: frost wedging
E N D
EARTH SCIENCE CHAPTER 7 WEATHERING EROSION SOIL FORMATION
7.1 Weathering • What is it? • 2 types
Cleopatra's Needle before after
Mechanical (physical)—rocks are broken down into smaller pieces • Gravity— • Temperature— Ex: frost wedging • Pressure-- Ex: exfoliation
Exfoliation of granite
Old Man in the Mountain Before…..
Review Definitions: • Weathering—rocks at Earth’s surface are broken down and changed • Erosion— • Deposition— • SO? All of these processes have been going on since Earth began!
Why is the Statue Of Liberty Green?
Chemical weathering— • Hydrolysis— • EX: decomposition of silicates • Oxidation— • EX: rust • Carbonic acid— Karst Topography
Acid rain—pH of rain < 5.6 neutral acidic basic
What can affect rates of weathering? • Climate— • Chemical— • Mechanical— • Type of rock— • Surface area— • Topography—erosion in areas of high relief (steep) w/ deposition in areas of low relief (flat)
Physical weathering in cool Dry climate
Chemical weathering In warm and wet climate
How does surface area Affect weathering?
Agents of erosion • Gravity— • Running water— • Rivers, streams, water falls • Glaciers— • Wind— • Plants and animals (biological)—
GLACIAL EROSION WIND EROSION PLANT EROSION
Rill Erosion
Gully erosion
1930’S DUST BOWL CAUSED BY EROSION OF TOPSOIL DUE TO EXTENSIVE OVERFARMING AND DROUGHT
A word about beaches…. • Ocean waves are constantly rebuilding and shaping coastlines • Sandbars can become barrier islands but they are not permanent! • Barrier islands threatened by hurricanes and beach erosion and rising sea levels
Barrier islands
Soil formation • What is soil? • Loose • Formed by chemical, mechanical and biological activity over very long periods of time • Humus—
Soil Texture: • Sand— • Silt— • Clay— SO? The texture of a soil affects its capacity to
Soil profile • A vertical sequence of soil layers • Residual soil— • Transported soil—