Weathering and Erosion Notes
This is a picture of a mountain in the Rocky Mountains.
1. weathering-when a rock is broken down into smaller pieces by wind, water, chemicals, plants, and animals.
2. rocks get broken down into smaller pieces called sediment.
3. two types of weathering-mechanical and chemical
4. mechanical weathering-process where rocks are physically broken into smaller pieces by wind, water, and ice or heat
5. mechanical weathering-caused by growing plants, burrowing animals, and expanding ice
6. Grand Canyon is an example of mechanical weathering
7. glaciers cause mechanical weathering
8. Great Lakes formed by glaciers
9. chemical weathering-minerals within rocks are broken down by removing or changing elements found in those rocks.
10. Carbon dioxide combines with water to form carbonic acid, a weak acid. Rotting vegetation dissolves in water and also forms a weak acid.
11. Carlsbad Cavern and Mammoth Cave are an example of chemical weathering.
12. plant roots can secrete enzymes that slowly eat into rocks
13. erosion is the movement of soil or rock by water, ice, or wind
14. weathering is the destruction and erosion is the movement
15. gravitational erosion-chunks of rock and even mountainsides sink and/or fall downhill caused by gravity
16. deposition-the dropping of sediment by water, wind, or ice.
17. flowing rivers transport (carry) weathered rock, water slows down and drops the sediment.
18. floodplain and river deltas are formed by deposition
19. sand dunes are formed by wind moving sediment
20. ocean currents move sand and can form barrier islands
21. soil formation is a product of weathering
22. soil consists of weathered rock(sediment) and decomposed organic material
23. sediment – three sizes, sand, silt, and clay
24. Sand feels gritty, silt feels smooth, and clay feels sticky
25. All soils are made up of varying amounts of these three main components silt, sand, and clay.
26. Sand and clay are easier to identify than silt. Silt is finer than sand and coarser than clay.
27. Silt gives soil good texture for crop production. Sand and clay can become hard and compacted without silt.
28. Soil is not only made up of pieces of weathered rocks, but it also contains animals, plants, decayed animals and plants, water, and air.
29. humus is the organic material in soil.
30. continued weathering releases minerals that plants need for growth
31. organic material is decaying and rotting plants, releases the minerals that the plant absorbed
32. organic means carbon based, we are carbon based.
33. mature soil is soil that has developed over thousands of years.
34. horizons-mature soil can be divided into three layers called horizons
35. the top or ÒAÓ horizon is called the topsoil, where shallow plant roots absorb water and nutrients, also home to insects and worms
36. the second or ÒBÓ horizon is the subsoil, where you find clay and minerals and the DEEP roots of plansts
37. the ÒCÓ horizon contains the weathered bedrock and is not part of the soil.