Eolian processes in general

• Eolian erosion, transportation, and deposition
• Types of dunes
• Typical landforms of arid mountainous deserts
• Distribution of the world's arid lands
• Glossery of obscure terms
• Informative websites with many pictures
  • USGS Deserts website
  • Satellite photos of eolian features on Earth
  • NASA eolian landforms site

Complexities of the System

• Modeling problems, as in all system studies - however, it is one of the best understood systems because the processes occur rapidly enough that we can see them happening.
• Preservation - accumulation space may not coincide with preservation space
  • Factors that promote preservation
    • Subsidence
    • Rise in water table - stabilization due to increase in vegetation
• Paleoclimate interpretation problems
  • System may not be in equilibrium with current conditions

Remote Sensing of Arid Lands

• New remote sensing systems are proving to be especially helpful in the effort to understand arid lands. Landsat satellites provide excellent data with which to monitor temporal variations in a given area.
• Radar systems have been used to look under the sand at features that are not visible in the field. This technology has been used to find unknown archaeological sites in Egypt and the Sudan.
• The Desert Winds Project was set up by the USGS in order to study climate conditions in the American southwest. The goal is to study long-term changes produced by wind in deserts of differing geologic and climatic types.
  • Tigges, Richard, Carol S. Breed, and Paula J. Helm, 1999. Design and operations of Geomet stations of the Desert Winds Project. USGS Professional Paper, 1598; 133-153.
• USGS Flagstaff Field Center website - provides information on the Desert Winds Project and data collected from the American deserts.

Eolian processes on Mars

• The Martian surface is greatly modified by the wind; atmospheric dust storms, dust devils and possible tornado tracks were all photographed by Viking.
• Other eolian features can be seen on the surface of Mars such as dunes, yardings, wind ripples, and wind scour.
• To see great pictures of these features and more check out these websites:
  • Dunes, dust storms, yardings, wind ripples, etc.
  • Dust storms
  • Dust devils
  • Cresent dunes
  • More dunes
  • For more pictures and tons of other information, check out NASA's Mars site
• Recent Mars eolian articles:
  • Bridges, Nathan T. et al, 1999. Ventifacts at the Pathfinder landing site. Journal of Geophysical Research. 104, 4; 8595-8615.
  • Edgett, Kenneth S. and Michael C. Malin, 2000. New views on Mars eolian activity, materials, and surface properties; three vignettes from the Mars Global Surveyor and Mars Orbiter Camera. Journal of Geophysical Research. 105, 1; 1623-1650.
  • Edgett, Kenneth S. and Philip R. Christensen, 1997. Rocks and Aeolian features in the Mars Pathfinder landing site region; Viking infrared thermal mapper observations. Journal of Geophysical Research. 102, 2; 4107-4116.
  • Greeley, Ronald et al, 1999. Aeolian features and processes at the Mars Pathfinder landing site. Journal of Geophysical Research. 104, 4; 8573-8584.
  • Kraft, Michael D. and Ronald Greeley, 2000. Rock coatings and aeolian abrasion on Mars; application to the Pathfinder landing site. Journal of Geophysical Research. 105, 6; 107-116.
• Also, the February 2001 issue of National Geographic has a great article on Mars with extraordinary pictures.

Desertification

• Desertification is the degradation of the land in dry areas caused by climatic changes and human activities. The result is the destruction of topsoil followed by loss of the land's ability to sustain crops, livestock or human activity.
• Humans have interfered with natural cycles and have increased the susceptibility of land to become desert wastelands. Over-grazing, land clearance, and over-cropping cultivated lands are all factors that increase desertification.
• Increased wind blown dust from the desertification of Africa has been linked to widespread destruction of Caribbean corals.
• Useful websites on desertification:
  • Desertification of arid lands
  • Desertification and climate change
  • Web resources on desertification
• Recent articles on desertification:
  • Albaladejo, J. et al, 1998. Soil degradation and desertification induced by vegetation removal in a semiarid environment. Soil Use and Management. 14, 1; 1-5.
  • Fonseca, R., F. Barriga, and W. Fyfe, 1998. Reversing desertification by using dam reservoir sediments as agriculture soils. Episodes. 21, 4; 218-224.
  • Lin Nianfeng, Tang Jie, Zhang Dianfa, 1999. The problem of the Quaternary, geological environment and desertification. Environmental Geology. 38, 1; 7-12.

Other references:

• Busch, Richard M. ed. 1992. Laboratory Manual in Physical Geology. 4th edition. Prentice Hall.
• Kocurek G. and Havholm K.G. 1993. Eolian sequence stratigraphy - a conceptual framework. In: Siliciclastic Sequence Stratigraphy: Recent Developments and Applications. pp. 393-409. Mem. Am. Ass. petrol. Geol., 58.
• Montgomery, Carla W. 1995. Environmental Geology. 4th edition. Wm. C. Brown Publishers.