Grain-Size End-Members of Anguli-Nuur Lake Core Sediments: Evidence for Moisture Variability in Northern China since the Last Deglaciation

Abstract

The common methods used for grain-size analysis have their own deficiencies and limitations in terms of explaining the genesis of grain-size components. In this study, the end-member modeling analysis method is applied to multi-mode grain-size distributions of core sediment from Anguli-nuur lake to help to understand the sediment provenance, transport processes and sedimentary environment. Four optimal end-members are unmixed, and three transport-deposition processes are revealed, including the runoff, wave and aeolian processes. The humidity index synthesized by the runoff and aeolian end-members in the core sediment is used to reconstruct the humidity variability in the East Asian monsoonal domain since the last deglaciation. Our record shows that the patterns of humidity variability are coincidentally linked with the monsoonal precipitation index from the same core and stalagmite record in southern China. The Holocene optimum is identified in early and middle Holocene. In addition, a series of millennial- and multi-centennial-scale dry events documented in our record are well correlated with the ice-rafted debris events in the North Atlantic. The results reveal that the grain-size record from Anguli-nuur lake is sensitive in response to moisture variability in northern China.

Keywords

• grain-size distribution
• last deglaciation
• northern China
• Anguli-nuur lake
• Asian monsoon