Large-Scale, Low-Amplitude Bedforms (Chevrons) in the Selima Sand Sheet, Egypt

dc.contributor.authorMaxwell, Ted A.
dc.contributor.authorHaynes, C. Vance, Jr.
dc.date.accessioned2008-10-28T18:01:26Z
dc.date.available2008-10-28T18:01:26Z
dc.date.issued1989
dc.description.abstractLandsat images of the Selima sand sheet in southwestern Egypt display alternating light and dark chevron-shaped patterns that occur downwind from low scarps and major dune fields. Images acquired between 1972 and 1988 indicate that these features move as discrete bedforms at a rate of up to 500 meters per year. Extremely long-wavelength (130 to 1200 meters), low-amplitude (10 to 30 centimeters) bedforms were measured in the field; the light chevrons seen in the orbital data may be thin accumulations of active sand sheet deposits in the lee of these bedforms. Dark chevrons contain an admixture of coarse-granule lag deposits that are continually winnowed by aeolian erosion on the windward sides of the large bedforms. Sediment transport budgets derived from orbital and field analyses suggest net movement of up to 83,000 cubic meters per year for a single light chevron; such measurements can be used as a check on similar calculations from dunes and other smaller scale features to determine sand transport budgets for large areas of the eastern Sahara.
dc.format.extent296204 bytes
dc.format.extent1179–1182
dc.format.mimetypeapplication/pdf
dc.identifier0036-8075
dc.identifier.citationMaxwell, Ted A. and Haynes, C. Vance, Jr. 1989. "<a href="https://repository.si.edu/handle/10088/6388">Large-Scale, Low-Amplitude Bedforms (Chevrons) in the Selima Sand Sheet, Egypt</a>." <em>Science</em>, 243, (4895) 1179–1182.
dc.identifier.issn0036-8075
dc.identifier.urihttp://hdl.handle.net/10088/6388
dc.language.isoen_US
dc.relation.ispartofScience 243 (4895)
dc.titleLarge-Scale, Low-Amplitude Bedforms (Chevrons) in the Selima Sand Sheet, Egypt
dc.typearticle
sro.description.unitNASM
sro.description.unitNASM-CEPS
sro.identifier.itemID71572
sro.identifier.refworksID58451
sro.identifier.urlhttps://repository.si.edu/handle/10088/6388

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