Knowledge Resource Center for Ecological Environment in Arid Area
DOI | 10.1002/jgrf.20101 |
Mechanisms of dust emission from Pleistocene loess deposits, Nebraska, USA | |
Sweeney, Mark R.1; Mason, Joseph A.2 | |
通讯作者 | Sweeney, Mark R. |
来源期刊 | JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
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ISSN | 2169-9003 |
EISSN | 2169-9011 |
出版年 | 2013 |
卷号 | 118期号:3页码:1460-1471 |
英文摘要 | Saltation bombardment is commonly believed to be the primary mechanism by which large quantities of dust can be generated. Direct entrainment of silt, on the other hand, is thought to generate minimal quantities of dust. If so, loess landscapes should rarely be major sources of dust unless disturbed by human activity. To test the mechanisms by which loess can be eroded by the wind, we used the Portable In-Situ Wind Erosion Lab (PI-SWERL). PI-SWERL tests were conducted on benches that were carved into loess at field locations. Coarse to fine loess was also collected and tested in a controlled setting using (1) dry, unconsolidated loess and (2) crusted loess. Results indicate that in most cases, the threshold friction velocity for silt is less than that for sand and that most dust generation occurs by direct entrainment of dust. Saltation, even in coarse loess, was nonexistent to intermittent. In a few cases, saltation of sand or soil aggregates preceded dust generation or enhanced emissions after direct entrainment began. Emission fluxes of loess are potentially high in both proximal and distal settings, suggesting that loess is easily entrainable if vegetation density is low. We hypothesize that an arid and windy climate of the late Pleistocene, paired with lower vegetation density, facilitated large-scale erosion of Peoria Loess in Nebraska to generate wind-aligned ridges and troughs. More broadly, our results indicate that loess landscapes have the potential to be major sources as well as sinks of dust. |
英文关键词 | loess dust direct entrainment PI-SWERL aggregates |
类型 | Article |
语种 | 英语 |
国家 | USA |
收录类别 | SCI-E |
WOS记录号 | WOS:000325978500020 |
WOS关键词 | CENTRAL GREAT-PLAINS ; WIND EROSION ; COLUMBIA PLATEAU ; DUNE ACTIVITY ; PEORIA-LOESS ; SOIL ; SALTATION ; DESERT ; ACCUMULATION ; TRANSPORT |
WOS类目 | Geosciences, Multidisciplinary |
WOS研究方向 | Geology |
资源类型 | 期刊论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/178440 |
作者单位 | 1.Univ S Dakota, Dept Earth Sci, Vermillion, SD 57069 USA; 2.Univ Wisconsin, Dept Geog, Madison, WI 53706 USA |
推荐引用方式 GB/T 7714 | Sweeney, Mark R.,Mason, Joseph A.. Mechanisms of dust emission from Pleistocene loess deposits, Nebraska, USA[J],2013,118(3):1460-1471. |
APA | Sweeney, Mark R.,&Mason, Joseph A..(2013).Mechanisms of dust emission from Pleistocene loess deposits, Nebraska, USA.JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE,118(3),1460-1471. |
MLA | Sweeney, Mark R.,et al."Mechanisms of dust emission from Pleistocene loess deposits, Nebraska, USA".JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE 118.3(2013):1460-1471. |
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