2. Geology 12 Presents

3. Outline: –Chp 14 Mass Wasting (Landslides) –Chp 15 Running Water –Chp 16 Groundwater –Chp 17 Glaciers and Glaciation –Chp 18 Wind and Deserts

4. Chp 18 Wind Sediments Erosion by: (because no protective vegetation) 1. Abrasion: sandblasting of rocks by sand (mainly quartz) –Ventifact = sandblasted boulder 2. Deflation: removal of loose particles by wind –Desert pavement = mosaic of rocks remaining after deflation

5. blowout

9. Desert Pavement

11. Suspension: carries silt and clay (think of dust storm) Saltation (bouncing): carries sand

15. Deposits –Sediments are well sorted by size (like rivers) Low energy: clay-silt loess Med-high energy: sand dunes –Sediment grains are well rounded, but slight pitting due to impacts –Mainly quartz (b/c Ford tough)

16. Dunes = large asymmetrical ripples –sand windwardleeward Dune migration saltation Slide/roll Cross bedding Much larger and steeper than stream ripples WIND

19. a) barchan dune b) parabolic dune c) longnitudinal dune d) transverse dune WIND depression

21. Barchan

23. Parabolic

25. Longnitudinal

27. Transverse

29. Star

30. 2. Loess = silt and clay –Blown from glacial outwash plains, deserts, and floodplains to areas where they have been stabilized by vegetation –From rich top soils of the Ukraine to Germany, China and the northern plains of U.S.

31. Shanghai loess deposits

32. Loess deposits

35. Review of Depositional Environments 1.Streams strata/beds, low angle, smaller, asymmetrical ripples Cross bedding a)Near source: semi-sorted and semi-rounded b)For 95% of streams: sorted and rounded

37. 2. Beaches and wave action Sorted and rounded (mainly sand) Strata/beds: low angle, smaller asymmetrical and symmetrical ripples

39. 3. Tidal Pools Sorted, fine grained (fine sand to clay) Smaller symmetrical ripples or mudcracks

40. 4. Wind: very well sorted and very rounded Strata/beds: high angle, large (up to 200m) Asymmetrical ripples & cross- bedding

42. 5. Lakes/Ocean Very fine grained (clay -> shale), Except graded bedding due to turbidity currents

43. 6. Ice: Unsorted and concoidal, & striated (scratched)

44. Continental rise/end of flood Shallow angle, small = river Steep, large = wind Tidal pool, dry lakeShallow angle, small = river Steep, large = wind

45. Do WS 18.1 Do Unit 4 Review WS Next Unit 5 Planetology (Chp 20)