Potential water sources for Late Quaternary Megalake Jilantai-Hetao, China, inferred from mollusk shell 87Sr/86Sr ratios
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- 作者：Yu-Xin Fan ; Fa-Hu Chen ; Guo-Xiao Wei ; David B. Madsen ; Charles G. Oviatt ; Hui Zhao ; Xi Chun ; Li-Ping Yang ; Tian-Lai Fan and Guo-Qiang Li
- 关键词：Strontium isotope ratios ; Water sources ; Late Quaternary ; Megalake Jilantai ; Hetao
- 刊名：Journal of Paleolimnology
- 出版年：2010
- 出版时间：March, 2010
- 年：2010
- 卷：43
- 期：3
- 页码：577-587
- 全文大小：537.7 KB
文摘
Lake Jilantai-Hetao, a megalake, was formed some time before 60–50 ka, along the Great North Bend of the Yellow River. The basin is now dry, with most of the area covered by aeolian sand. We are investigating this profound hydrologic change using a number of research approaches. Paleoshorelines of this megalake are best preserved in the Jilantai area in the southwestern portion of the megalake basin. We collected aquatic mollusk shells from littoral sediments at different altitudes around Jilantai and measured their strontium isotope compositions. 87Sr/86Sr ratios in shell carbonates are different between the high lake phase (~1,080–1,050 m altitude) and the low lake phase (~1,044–1,030 m altitude), with a small shift in average strontium ratios to more radiogenic values during the low lake phase. Based on regional hydrology and physical geography, we conclude that water from the Yellow River was the dominant water source supplying this megalake. 87Sr/86Sr ratios of modern water samples suggest the Yellow River was the dominant water source during the high lake phase, but that the relative contribution of Yellow River water to the megalake was reduced, and that the relative contributions of local precipitation and groundwater increased, during the low lake phase.