Geological Work of Wind for first Sem Geology.pptx

Geological Work of Wind

1. Geological Work of Wind By Abdul Bari Qanit M.Sc. Geology

2. Wind : Atmosphere is composed mainly of gases that are collectively known as air. Air in motion is called wind.

3. Geological Work of Wind Erosion Transportation Deposition

4. Wind Erosion Deflation : (Latin : deflare = To blow away). blow up the particles by strong wind. b. Abrasion : robbing the particles along with surface which gets break. c. Attrition : robbing the particles one with another and hence get break.

5. Wind Transportation Creeping : where the particles size are >1mm. So they rolling or creep the particles on the surface. Saltation : if the size of particles are 0.1 – 1 mm. the particles move as jumping's. Suspension : if the size of particles are o.oo1 – 0.01 mm. as in the dust size, they will be in form of suspension in the wind and will be carried from one place to others.

6. Erosional Landforms Deflation Hollow / Deflation basin Mushroom Rock / Pedester Wind Bridge Inselberg / Monad Rocks / Residual Hills Mesa and Butte Stone Lattice

7. Deflation Hollow / Deflation basin Deflation hollow  Enclosed depression produced by wind erosion.

8. Mushroom Rock / Pedester Because of their shape likeness to Mushroom.

9. Wind Bridge & Windows

10. Mesa & Butte A mesa is an isolated, flat-topped hill or mountain with steep sides that is smaller in area than a plateau. A butte is also a flat-topped hill with steep sides, though smaller in area than a mesa

11. Stone Lattice These are  formed  due to differential erosion. ...  Stone lattice -Differential erosion of hard and soft portions of rocks through abrasion produces pitted and fluted surfaces called  stone lattice .

12. Inselberg / Monad Rocks / Residual Hills Inselbergs , or isolated rock hills or mountains, are formed by erosion and long-term weathering.

13. Depositional Landforms Ripples Loess and Dunes / Sand Dunes

14. Ripples ripple  marks are sedimentary structures (i.e. bed forms of the lower flow regime) and indicate agitation by water (current or waves) or wind.

15. Loess A loosely compacted yellowish-grey deposit of wind-blown sediment of which extensive deposits occur e.g. in eastern China and the American Midwest.

16. Dunes A   dune  is a hill of loose  sand  built by Aeolian processes ( wind action) or the flow of water.

17. Dunes form in a lee Dunes are accumulations in the lee of local obstructions, possibly an upwind dune High velocity zone

18. Types of Dunes Transverse Dunes Star Dunes Barchans Dunes Parabolic Dunes Elongated Dunes

19. Star Dunes (Pyramidal Dunes): wind from multiple directions

20. Star Dunes Variable Wind Direction

21. Longitudinal Dunes : parallel to wind direction Constant wind direction, no vegetation

22. Longitudinal Dunes Constant wind direction, no vegetation

23. Transverse Dunes : lots of Sands, 90° to wind direction Massive volumes of sand, slow but consistent winds

24. Transverse Dunes Massive volumes of sand, low consistent winds

25. Barchans Dunes : half-moon shape Isolated Dunes, low sand supply, migrating across rock

26. Barchan Dunes Isolated – low sand supply; migrating across rock

27. Parabolic Dunes : curved towards wind direction Horns pinned by plants Typical of coasts

28. Parabolic Dunes Stabilized “horns" point upwind