1. 27. Wind work Dan Barker April 2009 North shore, Long Island Sound

2. Wind is one of several geological agents that can move mass over a distance by eroding, transporting, and depositing solid particles, although the particles are generally smaller than those moved by ice, gravity, or water.

3. When wind blows constantly in one direction for long time spans, it can effect a net loss in surface material, particularly on islands. Brava, Cape Verdes

4. Wind carrying sharp-edged pyroclastic glass particles is especially effective at cutting off vegetation at ground level, thereby removing protective cover from soil. Central High Desert, Iceland.

5. Particles carried by wind impact rock surfaces, etching harder components into relief. Aeolian Buttes, CA.

6. In San Gorgonio Pass, CA, wind from a constant direction has mobilized sand to produce these grooves in rock.

7. Sand blasting by glass shards has differentially etched variations in this exposure of the Green Tuff, Island of Pantelleria.

8. Lag pavement by wind erosion, Reykjanes Peninsula, Iceland

9. Wind can transport material on a small scale, as in this dust devil in the Danikil Depression, Ethiopia

10. or on a massive scale, such as this dust storm in the Atlantic west of Mauritania. Saharan dust reaches Austin, Texas at least once a year, on average.

11. The late Robert P. Sharp of CalTech investigated the vertical profile of wind transportation with this set-up at Palm Springs, CA. The accumulation in each collector was periodically removed and weighed. The second from the bottom contained the most (as bouncing sand grains). The top collector contained a little dust, plus an angry and hungry lizard. Most of the sand was transported less than a foot above the ground.

12. Dune sands derived from eroded coral reefs, west Maui.

13. Once sand has accumulated in a restricted patch, it forms a soft pad that traps bouncing sand grains, so that more and more sand accumulates in the same place. Kelso Dunes, CA. The next two images show the true scale of this dune.

14. On the crest of that dune, looking downward. Humans for scale.

15. On the crest of the same dune, looking upward from the same point as the previous image.

16. Wind ripples on a lee side, Kelso Dunes

17. Wind can remove small particles, leaving a lag concentrate of coarser ones, Note sunrise fog in background. Namibia.

18. Dunes accumulate in leeward spots. Dicker Willem, Namibia.

19. Red dunes, Namibia

20. Dense (dark) minerals concentrate on crests of dunes. Namibia.

21. Seasonally varying winds produce star dunes, as here in the Mojave desert, CA.

22. Finally, the most notorious locality for wind effects is Racetrack Playa, north of Death Valley, CA. Here blocks of dolomite from the surrounding mountains are stranded on the mud surface of a playa or intermittent lake. The blocks connect to trails of depressed and compacted mud that trace complicated paths across the playa. Even light materials such as wild burro droppings and sunglasses leave trails. Some articles in the popular press invoke "local anomalies in the gravitational field" or "extraterrestrial forces" to explain the horizontal migration of heavy blocks across the horizontal mud surface of the playa.

23. Racetrack Playa, California

24. Dolomite block on Racetrack Playa, CA.

25. Stone and track, Racetrack Playa, CA

26. Block and compressed track, Racetrack Playa, CA.

27. A track with no engraver; ice? Or removed by vandals?

28. Two tracks in opposite directions, with blocks at both ends. The prevailing hypothesis is that dolomite blocks and other objects were frozen in a thin layer of ice over a wet mud surface. Winds moved plates of ice in different directions, and the objects gouged the tracks. The other possibility, of increasing probability. Is vandalism. No one has ever seen a block move.