Dune mobility and aridity at the desert margin of northern China at a time of peak monsoon strength
- 1Department of Geography, University of Wisconsin Madison, 550 N. Park Street, Madison, Wisconsin 53706, USA
- 2School of Geographical and Oceanographical Sciences, Nanjing University, Nanjing 210093, China
- 3College of Tourism and Environment, Shaanxi Normal University, 199 Chang'an South Road, Xi'an, 710062, China
- 4Illinois State Geological Survey, 615 E. Peabody Drive, Champaign, Illinois 61820-6964, USA
- 5School of Natural Resources, University of Nebraska–Lincoln, Lincoln, Nebraska 68583-0996, USA
- 6Center for Climatic Research and Department of Atmospheric and Oceanic Science, University of Wisconsin-Madison, 1225 W. Dayton Street, Madison, Wisconsin 53706-1695, USA
- 7Department of Geosciences, University of Nebraska–Lincoln, Lincoln, Nebraska 68588, USA
Abstract
Wind-blown sands were mobile at many sites along the desert margin in northern China during the early Holocene (11.5–8 ka ago), based on extensive new numerical dating. This mobility implies low effective moisture at the desert margin, in contrast to growing evidence for greater than modern monsoon precipitation at the same time in central and southern China. Dry conditions in the early Holocene at the desert margin can be explained through a dynamic link between enhanced diabatic heating in the core region of the strengthened monsoon and increased subsidence in drylands to the north, combined with high evapotranspiration rates due to high summer temperatures. After 8 ka ago, as the monsoon weakened and lower temperatures reduced evapotranspiration, eolian sands were stabilized by vegetation. Aridity and dune mobility at the desert margin and a strengthened monsoon can both be explained as responses to high summer insolation in the early Holocene.
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- Received 13 March 2009.
- Revision received 26 May 2009.
- Accepted 28 May 2009.
- © 2009 Geological Society of America
