Most deserts have highly angular landscapes due to mechanical weathering dominating over deposition. Desert rainfall is infrequent, intense, and unreliable, causing flash flooding and erosion. The three main types of deserts are ergs, which are large seas of sand; regs with thin desert pavements of stones; and hamadas dominated by bedrock. In deserts, fluvial erosion carves steep canyons, while deposition forms alluvial fans. Aeolian processes cause erosion through deflation and abrasion, and deposition forms migrating dunes like barchans and transverse dunes. Desert terrain also includes basin and range topography with pediments and playas, and resistant rock landforms emerge like insel

1. Arid Landforms

3. angular particles of weathered rock; bedrock outcrops

7. Death Valley, July 15, 1999

8. Las Vegas Flash Flood

10. vegetation rare

14. Hamada - bedrock predominates

15. Desert varnish - oxidation of iron and manganese, useful for dating desert surfaces

19. Virga

20. Joshua Tree N.P.

21. Slot Canyon

22. The Narrows, Zion N.P., Utah

25. sand storms - only very near the surfaceAeolian Deposition - dunes form and shift where winds and terrain combine to slow the winds or block the movement of dunes.

27. Dust Storm, Senegal Sand Storm

28. AEOLIAN (WIND) PROCESSES/LANDFORMS

29. Types of Dunes BARCHAN TRANSVERSE DUNES SEIFS

30. Types of Dunes Barchans- migrating crescent dune with horns pointing downwind; form where strong winds blow in a consistent direction. Move fast. Common in central Asia and Sahara. Can reach hundreds of feet in height.

31. Transverse Dunes - parallel waves of crescent dunes perpendicular to wind direction; migrate downwind. Found in areas with large supply of sand.

32. Seifs - multiple very long narrow, parallel dunes. May be caused in areas with at least two dominant wind directions. Can be tens of miles long. Common outside of U.S.

33. Namib Desert Star Dunes

34. BASIN AND RANGE TOPOGRAPHY

35. Piedmont - gently sloping land that extends out from base of mountains. Pediment - sloping bedrock at base that develops.

36. Badwater, Death Valley, CA

38. Playas

39. Mesa and Scarp Topography

40. Differential Erosion

44. Uluru (Ayer’s Rock), Australia

45. Inselberg - “island mountains” rise abruptly out of desert landscapes Bornhardt - highly resistant rock landform; a type of inselberg. Kata Tjuta (The Olgas), Australia

46. Bornhardt, Arches National Park, Utah

47. Delicate Arch, Arches National Park, Utah