1. Evidence of Erosion and Deposition Sarah Fink Minerva Central School 2006

2. Agents of Erosion Running water Wind Ice (Glaciers) Gravity Waves http://people.csail.mit.edu/manoli/gallery/goldengate/waves.jpg http://www.peterbindon.com/Photography/Images-Photography/Landscape/Running_Water.jpg http://www.uwsp.edu/geo/faculty/ritter/images/lithosphere/glacial/piedmont_glacier_Baffin_GSC_2crev.jpg http://www.me3.org/issues/wind/zondturbines.jpg http://usuarios.cmg.com.br/~hp-adrenace/adrena2.jpg

3. Quiz Yourself! For each of the following 13 pictures, write down the major agent(s) of erosion. Remember, your choices are: –Running water –Wind –Ice (Glaciers) –Gravity –Waves Note: sources for photos in the quiz are noted in the answers.

4. Example 1 Answer

5. Example 2 Answer

6. Example 3 Answer

7. Example 4 Answer

8. Example 5 Answer

9. Example 6 Answer

10. Example 7 Answer

11. Example 8 Answer

12. Example 9 Answer

13. Example 10 Answer

14. Example 11 Answer

15. Example 12 Answer

16. Challenge Question: Answer

17. How Did You Do?? Even if you didn’t get all of the answers correct, you should be able to recognize some patterns for the agents of erosion we discussed. Let’s see some more pictures and come up with some “rules” for identifying and classifying eroded rocks.

18. Running Water Abrasion of stream bed (can form potholes) Dissolution Scour (lifting of loose particles) Sandbars Point bars Meanders Floodplains Levees Deltas Alluvial fans

19. Water erosion – dry streambed http://www.bioschool.co.uk/bioschool.co.uk/images/images/water%20erosi on_JPG_JPG.jpg Stream gully Dry delta

20. Water erosion – river rock http://www.ecotrust.org/copperriver/crks_cd/content/pages/photographs/images/ riverrock.jpg

21. Water erosion – kettle holes http://www.alabamaatheist.org/naturalism/graphics/040607_017.jpg

22. Water erosion - Grand Canyon http://www.grand-canyon-tours.biz/Grand%20Canyon%203.jpg Colorado River

23. Water erosion on Mars? http://nmp.jpl.nasa.gov/ds2/mission/images/water-erosion.gif

24. Characteristics of erosion by running water:

25. Wind Deflation Abrasion Dunes Loess (layers of fine silt)

26. Wind erosion - ventifacts http://www.uwgb.edu/dutchs/EarthSC202Slides/windslid.htm Flat sides show the prevalent wind direction

27. Wind erosion – sand dunes http://www.ncdc.noaa.gov/paleo/drought/images/sanddune_thumbnail.jpg

28. Wind erosion – ripple marks http://academic.emporia.edu/aberjame/struc_geo/primary/prim17.jpg

29. Wind erosion – desert pavement http://www.uwgb.edu/dutchs/geophoto/aeolian/DPAVMT1.jpg

30. Wind erosion in Antarctica http://www.uwgb.edu/dutchs/geophoto/aeolian/ANTVACX.jpg

31. Wind erosion http://www.yorkshirewalks.org/diary/nidd2/2008.jpg

32. Wind erosion – Sahara Desert http://www.cosmicharmony.com/Ia/NaturWnd/Sahara.jpg

33. Wind-eroded rocks in Zion, UT http://www.solarnet.org/Travel/US/Rock15MV.jpg

34. Sand dunes on Mars http://images.spaceref.com/news/2004/2004.08.09.R1601009.gif

35. Characteristics of erosion by wind:

36. Ice/Glaciers Ice wedging/Gravity Abrasion (striations, scouring, polishing) Plucking (carrying loose sediment) Till Moraine Drumlin Meltwater deposits

37. Glacial erosion – striations http://gemini.oscs.montana.edu/~geol445/hyperglac/eroproc1/boulderstriea2.JPG Striations (scratches) are parallel

38. Glacial erosion – striations http://tauceti.sfsu.edu/~chris/wonderland/manoj087.jpg

39. Glacial erosion – polish and erratic http://www.tarol.com/cathedral_erratic_glacial_polish.JPG

40. Ice wedging http://facweb.bhc.edu/academics/science/harwoodr/GEOL101/Study/Images/ icewedge.jpg http://www.visualsunlimited.com/images/ watermarked/112/112071.jpg

41. Hoodoos – stone columns http://www.cornellcollege.edu/geology/rdenniston/Texas%20pics/tent%20rocks.jpg http://www.izix.com/personal/travel/utah/images/hoodoos-w.jpg Find out more! End Quiz

42. Formation of Bryce Canyon A combination of frost wedging and rainwater are the sources of weathering and erosion that cause the “hoodoo” formations found in Bryce Canyon, Utah. “Acid” rain formed by carbon dioxide in the atmosphere dissolves the weaker calcite-based limestone, but the stronger mudstone, siltstone, and dolomite layers weather more slowly. This results in the layering found in the rock formations. The average rate of erosion is 2-4 feet per 100 years. http://www.nps.gov/brca/geology_hoodoos.html

43. Characteristics of erosion by ice:

44. Gravity – Mass Wasting Slump Rock fall Landslide / debris flow Creep Solifluction (in areas with permafrost) Talus

45. Gravity as agent of erosion http://www.enhg.org/gallery/shams/shams11.jpg

46. Rock slides in Alaska http://www.alaskahunts.net/alaska/hikingonslide.JPG

47. Gravity – talus slopes at cliff base http://www.kidscosmos.org/kid-stuff/mars-trip-graphics/talus-boulders-18-2p.jpg

48. Soil creep caused by gravity http://www.mountainnature.com/images/Geology/Large/SoilCreep01.jpg

49. Solifluction – due to permafrost http://www.fettes.com/Cairngorms/images/solifluction_siberia.jpg Alternate seasons of freezing and thawing of saturated permafrost results in gradual soil movement downhill.

50. Characteristics of erosion by gravity:

51. Waves (shoreline) Waves, tides, currents Pounding Abrasion Pressure Dissolution Scour Cliffs, arches, platforms, caves, stacks Beaches Barrier islands Spits Sandbars Bay-mouth bars Tombolos

52. Beach erosion by waves http://people.albion.edu/KAT10/dp/beach%20erosion.jpg http://epod.usra.edu/archive/images/roll 1dx-21.jpg

53. Sea arches and stacks http://gpc.edu/~pgore/Earth&Space/erosion.html http://www.nps.gov/pwro/piso/minkstdy/images/stacks.jpg Wave action and changing tides cause these formations

54. Ripple marks – wave action http://www.downtheroad.org/images/Photo%20Album/New_Folder7/DSC00091.JPG

55. Ancient ripple marks preserved in sedimentary rock http://www.calstatela.edu/faculty/acolvil/sediment/giant_ripples.jpg

56. Characteristics of erosion by waves:

58. Glacial till and outwash (deposited soil) http://www.hi.is/~oi/Water%20erosion%20alongside%20a%20flute%20on%20 Kringilsarrani%20.JPG