1. Geol 202: Physical Geology Organization second lecture: deserts and wind action

2. Chapter 18 Deserts & the Work of Winds

3. ARID LANDS – CAUSES & TYPES

4. Deserts worldwide

5. Atmospheric convection cells

7. Rain shadow

10. Sonoran Desert vegetation, Tucson AZ

11. GROUND PROCESSES IN ARID LANDS

12. Desert varnish, Panamint Valley CA

13. Rock varnish, Utah

14. Desert varnish, Death Valley

15. Desert pavement, Panamint Valley

16. Desert pavement pebbles, Death Valley

17. WORK OF WATER IN DESERTS

18. Desert landscape features

19. Arroyo, flash flood, NE Arizona

22. Playa

23. Stages in pediment formation

24. Ayers Rock, Australia – inselberg

25. WORK OF WINDS

26. Aeolus Greek god of winds

31. Ventifacts – Lake Vide, Victoria Valley, Antarctica

32. Ventifacts

33. Yardang in Roman Playa, Egypt

34. Yardang compact lake sediment Rogers Lake Playa Southern California

35. Desert and wind abrasion

36. Erosion (Pillar of God) sandstone butte on pyramid of shale

37. Colorado Plateau landforms

38. Monument Valley

39. Butte in Monument Valley, Arizona

40. EOLIAN DEPOSITION

41. Particle size is used to distinguish among various clastic rock types

44. Erosion of soil – Texas

45. Erosion – St Park field, 1 m deflation since 1977

46. Grand Mar

47. Eolian sand ripples, Monument Valley, Arizona

48. Ripple marks Death Valley

49. Modern eolian ripple marks

50. Wind dunes

51. Great Sand Dunes, Colorado (200m, some of tallest in world)

52. Great Sand Dunes N Pk, Colorado

54. Dra dunes, Africa’s Namib Desert

55. Dune types

56. Transverse dunes

57. Sand dunes, Tsangpo River

58. Transverse and barchans – Takla Makan Desert, China

59. Longitudinal dunes Simpson Desert, Australia

60. Longitudinal dunes

61. Dune types

62. Barchan dunes west of the Salton Sea, CA

63. Barchan dunes

64. Transverse dunes; crescent shaped barchan dunes

65. Parabolic dune, Michigan

66. Star dunes

67. Sand Hills of Nebraska – North America’s largest dune field

68. Loess in U.S.

69. Boulder, Colorado dust storm

70. Loess blowing from deflation of floodplain downstream from Tasman Glacier, NZ

71. Loess cliff

72. Yellow River Xian, China

73. Loess cliff, Miss.

74. Loess house in loess cave Xian, China

75. Loess paleosol in Peoria Loess, Vicksburg (east 2 miles on I-20)

76. Loess paleosol below Adam’s hand Vicksburg (east 2 miles on I-20)

77. Loess Yellow River loess plateaus

78. Paleosols developed on loess

79. DESERTIFICATION

80. Encroachment on pasture – sand dune in Niger

81. Barchan dunes – Danakil depression (Ethiopia) irrigated field

82. next: Chapter 17 – Glaciers