This document summarizes key concepts about weathering and soil formation: 1. Weathering is the process that breaks down rock into smaller fragments through mechanical and chemical processes. Chemical weathering causes chemical changes through reactions with water, oxygen, carbon dioxide, living organisms, and acid rain. Mechanical weathering breaks rock into pieces through processes like freezing and thawing. 2. Soil is formed over long periods of time as weathered rock and organic matter accumulate and layer. Factors like climate, vegetation, rock type, slope, and time influence soil formation. 3. Soil conservation techniques help reduce erosion, including contour plowing, terracing, crop rotation, shelter belts, proper grazing, no

1. WEATHERING and SOIL

2. 1. _____________ - the process that breaks rocks down into smaller and smaller fragments. 2. _________- carrying pieces away 3. _______________- the principle that states that processes operate the same as they did in the past 4. - weathering; breaking into pieces caused by freezing and thawing Weathering mechanical erosion uniformitarianism

3. A.______________- water freezes in cracks and expands Ice wedging

4. B. ____________ - roots grow under and into other materials C.____________-digging can expose new rock surfaces to weathering Plants Animals

5. Vegetation growing in Joints

6. D. __________-rubbing or pulling due to __________, ___________, or _______ abrasion gravity, running water wind

7. ________________- peeling action of weather rocks. exfoliation

8. This is a picture of the Half Dome. The rock is peeling away from the mountain in layers just like an onion. This is exfoliation.

9. 5. ________ weathering; process that causes chemical changes to occur ; caused by the action of water, oxygen, CO ², living organisms and acid rain chemical

10. ______________- carbonic acid (carbon dioxide and water) react with rock to form new substances. Carbonation

11. B. _________- oxygen combines with metallic materials (such as iron) to form rust. oxidation

12. C. ______________- organisms that break down the remains of dead organisms (fungi, bacteria, worms) decomposers

13. permeability 6. ___________ rocks with a _______ density; many spaces low

14. impermeability 7.________________rocks with a ____ density; tightly packed high

15. Look at the 2 examples of WEATHERING Chemical Mechanical Are these mechanical or chemical?

16. 8. Rates of weathering A._____________- eventually break down. All rocks

17. B. _________- rocks decompose ______ if they crystallize fast. (Ex. Marble will decompose faster than granite). Igneous faster

18. C. Sedimentary rocks decompose faster in _______ climates. humid

19. D. __________and ____________ speed up chemical weathering. Heat moisture

20. E. _____________and __________ speed up mechanical weathering. Freezing thawing

21. 9. mixture of weathered rock, decayed organic matter, mineral fragments, water, and air. 10. Factors that affect soil formation A. B. C. D. E. soil- Climate Slope of land Type of rock Types of vegetation Amount of time rock has been weathered

22. 11. __________- layer of solid rock beneath the soil layers bedrock

23. 12._______ - decayed organic matter . humus

24. 13.- ______ ________ different layers of soil . soil horizon 14. _____ _______ - vertical layering of all soil horizons . soil profile topsoil subsoil

26. 15. ____- soil made up of equal parts of clay, sand, and silt; great for growing plants loam

27. 16. Causes of erosion ___________ ___________________ slope agricultural cultivation

28. C. __________________ -the removal of plants, trees, etc. for lumber, farming and grazing. deforestation

29. D. ______________ Overgrazing

30. E. _____________________ Urban construction

31. 17. Soil Conservation Techniques

32. A. ______________ - cultivating sideways rows on a hill. contour plowing

33. B. _________ - building step-like levels on a hill. terracing

34. _____________and ____________-planting different crops in different places each year. strip cropping crop rotation

35. D. ______________ - planting trees to block the wind. shelter belt

36. E. _____________ ____________-not allowing animals to eat too much of any one pasture area. F.__________________- leaving plant stalks to be tilled under in the spring when planting. Proper grazing management No till-farming

37. G. Use of _____, ____________, _____, _________ or ____________ to slow erosion. H.____________- planting trees on barren areas mulch concrete walls stone wood mats plastic coverings reforestation

38. 18._____________ - soil is damaged from little or no rainfall causing desert-like conditions. desertification

40. 19. ___________- area of the Midwest where in the 1930’s the soil was ruined by poor farming techniques Dust Bowl

41. 20. ________- water soaks into lower soil horizons leaching

43. The End