Geochemical evidence for an Eolian sand dam across the North and South Platte rivers in Nebraska

Muhs, D. R.; Swinehart, J. B.; Loope, D. B.; Been, J.; Mahan, S. A.; Bush, C. A.

Abstract:

Geochemical and geomorphic data from dune fields in southwestern Nebraska provide new evidence that the Nebraska Sand Hills once migrated across the North and South Platte rivers and dammed the largest tributary system to the Missouri River. The Lincoln County and Imperial dune fields, which lie downwind of the South Platte River, have compositions intermediate between the Nebraska Sand Hills (quartz-rich) and northeastern Colorado dunes (K-feldspar-rich). The most likely explanation for the intermediate composition is that the Lincoln County and Imperial dunes are derived in part from the Nebraska Sand Hills and in part from the South Platte River. The only mechanism by which the Nebraska Sand Hills could have migrated this far south is by complete infilling of what were probably perennially dry North Platte and South Platte river valleys. Such a series of events would have required an extended drought, both for activation of eolian sand and decreased discharges in the Platte River system. A nearby major tributary of the North Platte River is postulated to have been blocked by eolian sand about 12,000 14C yr B.P. We propose that an eolian sand dam across the Plattes was constructed at about this same time. (C) 2000 University of Washington.

Genre:

Article

ProdID:

70022852

Citation Author:

Muhs, D. R.; Swinehart, J. B.; Loope, D. B.; Been, J.; Mahan, S. A.; Bush, C. A.

Citation Contributing Office:

Citation Datum:

Citation Day:

Citation Edition:

Citation Editor:

Citation End Page:

222

Citation Issue:

Citation Keywords:

Citation Language:

English

Citation Larger Work Title:

Quaternary Research

Citation LatN:

Citation LatS:

Citation LonE:

Citation LonW:

Citation Month:

Citation No Pagination:

Citation Number Of Pages:

Citation Online Only Flag:

Citation Phsyical Description:

Citation Projection:

Citation Public Comments:

Citation Publisher:

Citation Series:

Citation Series Code:

Citation Series Number:

Citation Search Results Text:

Geochemical evidence for an Eolian sand dam across the North and South Platte rivers in Nebraska; 2000; Article; Journal; Quaternary Research; Muhs, D. R.; Swinehart, J. B.; Loope, D. B.; Been, J.; Mahan, S. A.; Bush, C. A.