Re-assessment of the paleoclimate implications of the Shell Bar in the Qaidam Basin, China (SCI)

CORC > 寒区旱区环境与工程研究所 > 中科院寒区旱区环境与工程研究所（未分类） > 期刊论文

	Re-assessment of the paleoclimate implications of the Shell Bar in the Qaidam Basin, China (SCI)
	Mischke S. ; Lai Z. P. ; Zhang C. J.
刊名	Journal of Paleolimnology
	2014
卷号	51 期号:2 页码:179-195
英文摘要	The Shell Bar in the Qaidam Basin, China, is a prominent geological feature composed of millions of densely packed Corbicula shells. Since the mid 1980s, it has been regarded as evidence for existence of a large lake during Marine Isotope Stage (MIS) 3 in the presently hyper-arid Qaidam Basin. Early studies suggested the bivalve shells accumulated at the shore of a large lake, whereas more recent work led to the conclusion that the Shell Bar was formed within a deeper water body. Based on our re-assessment of sediments and fossils from the Shell Bar, investigation of exposed fluvio-lacustrine sections upstream of the Shell Bar and study of nearby modern streams, we infer that the Shell Bar represents a stream deposit. Corbicula is a typical stream-dweller around the world. Preservation of Corbicula shells of different sizes, as well as occurrence of many articulated shells, provide evidence against post-mortem transport and accumulation along a lake shore. Additionally, the SE-NW alignment of the Shell Bar is similar to modern intermittent stream beds in its vicinity and corresponds to the present-day slope towards the basin centre further NW, and furthermore, the predominantly sandy sediments also indicate that the Shell Bar was formed in a stream. Abundant ostracod shells in the Shell Bar sediments originated from stream-dwelling species that are abundant in modern streams in the vicinity of the Shell Bar, or in part from fluvio-lacustrine sediments exposed upstream of the Shell Bar, as a result of erosion and re-deposition. Deflation of alluvial fine-grained sediments in the Shell Bar region and protection of the stream deposits by the large and thick-walled Corbicula shells reversed the former channel relief and yielded the modern exposure, which is a prominent morphological feature. Occurrence of Corbicula shells in the Qaidam Basin indicates climate was apparently warmer than present during the formation of the Shell Bar because Corbicula does not live at similar or higher altitudes in the region today. Because the Shell Bar is no longer considered a deposit formed within a lake, its presence does not indicate paleoclimate conditions wetter than today.
收录类别	SCI
公开日期	2015-12-24
内容类型	期刊论文
源URL	[http://ir.casnw.net/handle/362004/24915]
专题	寒区旱区环境与工程研究所_中科院寒区旱区环境与工程研究所（未分类）_期刊论文
推荐引用方式 GB/T 7714	Mischke S.,Lai Z. P.,Zhang C. J.. Re-assessment of the paleoclimate implications of the Shell Bar in the Qaidam Basin, China (SCI)[J]. Journal of Paleolimnology,2014,51(2):179-195.
APA	Mischke S.,Lai Z. P.,&Zhang C. J..(2014).Re-assessment of the paleoclimate implications of the Shell Bar in the Qaidam Basin, China (SCI).Journal of Paleolimnology,51(2),179-195.
MLA	Mischke S.,et al."Re-assessment of the paleoclimate implications of the Shell Bar in the Qaidam Basin, China (SCI)".Journal of Paleolimnology 51.2(2014):179-195.