Osl chronology of the sand hills of Xingkai Lake, Northeast China and its implication for environmental changes since 200 Kyr BP

Abstract

Xingkai (Khanka) Lake, on the Sino-Russian boundary, is the largest freshwater lake in northeast Asia. It features multiple sand hills to its northern bank formed since the late Pleistocene when the lake surface was larger. Highaccuracy chronology is needed to constrain the age of different historical high water level (big-lake) periods, in order to understand the relationship between climate and environmental change. We first tried to use the optically stimulated luminescence (OSL) dating method to date 18 quartz samples from the four sand hills of Xingkai Lake. The analysis of grain-size and magnetic susceptibility (MS) for the nearest two sections were also undertaken to understand the formation mechanism of the sand hills. The OSL chronology indicates that there had been four big-lake periods at 193–183, 136–130, 24–15 and 3–0 kyr BP, respectively. From regional comparisons, we found that these big-lake periods were associated with relatively colder climates, broadly corresponding to the Marine Isotope Stage (MIS) 6, MIS 2 and the late Holocene. This hypothesis is supported by further high resolution OSL chronology for a sediment core XK from Xingkai Lake. OSL chronology for this core reveals contrasting higher sedimentation rates in MIS 6, MIS 4, MIS 2 and late Holocene, compared to other periods. The higher sedimentation rates associated with the cold periods may be related to the rapid accumulation of the <16 _m fraction sediment (comprising more than 80–90 % sediment of core XK) under relatively static water conditions.