1. Chapter 8 At end of period you will get a class work grade for attentiveness and note completion…and you will have a QUIZ on the notes.

2. Chapter 8 Weathering: the metamorphose process in which rock goes from one state of appearance and/or chemical structure into another

3. Weathering Mechanical Weathering Chemical Weathering Erosion

4. Mechanical Weathering Mechanical weathering: type of weathering that breaks rock into smaller pieces without changing its chemical composition.

5. Mechanical Weathering cont. Ice wedging: when large amounts of water gets into the cracks of rocks and it repeatedly freezes and thaws.

6. Mechanical Weathering cont. Frost action: When small amounts of water gets into the cracks of rocks and it repeatedly freezes and thaws.

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9. Mechanical Weathering cont. Plant and root action: when the force of plants, trees, and/or roots break apart rock into smaller pieces. Exfoliation: the peeling of surface layers from a rock structure.

10. Mechanical Weathering cont. Wetting and drying: clay particles in rock repeatedly get wet and then dry out making the rock swell and shrink.

12. Mechanical Weathering cont. Spheroidal weathering: edges of a rock wear away faster than the center of a rock making it spherical in shape.

13. Mechanical Weathering cont. Abrasion: grinding action of rock produces rounded boulders, pebbles, and sand grains.

14. Practice Link

15. Chemical Weathering Chemical weathering: type of weathering that uses water and/or air to change the chemical composition of rock or dissolve it away.

16. Chemical Weathering cont. Hydrolysis: chemical reaction of water with other substances. Oxidation: chemical reaction of oxygen with other substances.

17. Chemical Weathering cont. Carbonic acid: carbon dioxide and water form a weak acid which dissolves away certain minerals in rock.

19. Chemical Weathering cont. Natural acids: natural acids from plants and animals combine with water to dissolve away certain minerals in rock.

20. Erosion USGS states, “soon as a rock particle (loosened by one of the two weathering processes) moves, we call it erosion or mass wasting. Mass wasting is simply movement down slope due to gravity.

21. Erosion Rock falls, slumps, creeps, avalanches, and debris flows are all examples of mass wasting. We call it erosion if the rock particle is moved by some flowing agent such as air, water or ice.

22. Creep or Earth flow

23. Erosion cont. So, here it is: if a particle is loosened, chemically or mechanically, but stays put, call it weathering. Once the particle starts moving, call it erosion.

24. Weathering and Erosion: A Dynamic Duo Frost action / ice wedging may lead to rock falls Exfoliation can lead to rock slides

25. MASS WASTING SITE

26. Practice