4. Weathering: -The Breakdown of rock due to physical or chemical changes *TWO MAIN TYPES OF WEATHERING* 1) Physical Weathering: -Changes the size or shape of a rock- for example, by breaking it into smaller pieces- without changing its chemical composition

5. Examples: 1)Frost Action: - important agent of weathering in climates that experience above and below 0 o C -water seeps into pores of rocks, freezes and therefore expands, causing cracks in the rocks. - over an extended period of freezing and melting, the rock will crumble

6. Plant Roots: -Grow in the crack of rocks Animals: -animals that burrow beneath the ground -roots expand in the crevices of rocks and gradually push the rock apart - constantly expose new rock surfaces to weathering

7. Abrasion: -rocks carried by a stream, bump and rub against one another. These collisions cause the rock to break down. -wind, moving ice and gravity are also agents of abrasion.

8. CHEMICAL WEATHERING: - requires heat energy and often water - changes the chemical composition of the rock, forming new substances. Ex: -Feldspars uplifted to the earth’s surface come in contact with water and chemically weather to clay. -takes place more rapidly in warm and moist climates

9. - rusting of a nail: iron rusts in the presence of moisture. O 2 combines with the iron atoms and forms rust

11. SOIL- the mixture of weathered rock and organic remains that cover bedrock. - under natural conditions, both physical and chemical weathering play a part in soil development. Physical weathering; breaks solid rock into small particles Chemical weathering: changes hard minerals into softer forms

12. - the decay of organic remains produce organic acids that accelerate chemical weathering

13. SOIL HORIZONS: - created by the weathering of bedrock * the top layer is the best for growing crops. Rich in dark colored organic remains called humus *ground water filtration does transport some minerals to the lower layers * the lowest layer of soil is generally composed of broken up bedrock.

14. ORGANIC MATERIAL BROKEN BEDROCK- SOME ORGANIC MATERIAL COMPLETELY BEDROCK

15. Important things to know about soil * It takes 100 to 400 years for one centimeter of topsoil to form * Destruction of plant cover and poor farming and mining practices leave soil exposed and unprotected. It is then quickly carried away by water and wind

17. Sediments: -rocks that have been broken into various sized fragments. Erosio n: Involves the transporting of sediments away from their place of origin and depositing them elsewhere

18. - running water transports sediments in several ways 1) Erosion by water : - the smallest particles remain suspended in solution because they cannot be filtered out - largest most dense particles are rolled or bounced along the streambed - low density material such as organic remains are carried along the surface of the water by flotation

19. - water velocity indicates transported particle size Larger= greater velocity smaller= lower velocity The Velocity Of Streams -as stream gradient and or water quantity increases,, velocity of water increases. * most erosion takes place when streams are in flood

20. - slowest moving water sticks to the inside of the bends, causing deposition on the inner banks - fastest flowing water swings at the outside of river beds causing erosion along the outer banks.

22. Erosion By Wind - wind can carry away sand silt and clay -occurs mainly in dry areas such as deserts, because there is not much plant life to hold soil in place -wind erodes by abrasion

23. Erosion by Ice: Glacier: large mass of ice that moves due to its weight under gravity. -as it moves, it picks up and carries loose rock material -acts like a huge abrasion system - when ice melts, unsorted deposits are left behind - rocks are left angular and often scratched

24. WHAT IS DEPOSITION? - occurs when agents of erosion, deposit or lay down particles and fragments of sediments

25. - Factors That Affect Deposition Particle Size: Smaller particles such as clay and silt, settle more slowly than cobbles and boulders Particle Shape: Flat angular pieces of sediment settle more slowly because of their increased surface area and friction with the water. -smooth, rounded particles settle more quickly

26. Particle Density : Among particles of the same average size and shape, more dense particles settle faster. Settling Rate and Settling Time: - as the rate of settling increases, settling time decreases

27. Sorting of Sediments: Horizontal Sorting: -largest, roundest and densest particles are deposited first near the oceans coastline, while the smallest, flattest and least dense are carried further form the shoreline Vertical Sorting: Where particles sort out from bottom to top in a layer

28. Deposition in Streams - sediment can cause sand bars in slower sections of the stream Deposition By Wind: -Like running water, wind deposits sediments in layers Ex. Sand dunes SORTED DEPOSIT: EX: When streams slow down, largest particles settle out first, then smaller particles.

29. Deposition by Gravity: - does not create sorted sediments. (many different sediment sizes mixed together. Deposition by Glaciers: - occurs when glaciers melt and sediments are released. - unsorted unless glacial sediments are deposited as a result of melt-water

30. NEW YORK AND THE ICE AGES - as recently as 20,000 years ago, most of New York was covered by a continental ice sheet. Alpine Glaciers: -occur in mountain regions -will flow downhill under its own weight due mainly to slope. -Flow at a rate of a few centimeters to several meters per day -ice rubbing against surrounding rock carves out valleys

31. Continental Glaciers - known as ice sheets - responsible for most glacial features in NYS - rock carried within the glacier that causes erosion of the land Striations: Parallel grooves and scratches in bedrock