A combined luminescence and radiocarbon dating study of Holocene lacustrine sediments from arid northern China

Abstract

Arid northern China is an ideal place for the reconstruction of palaeoenvironmental changes, for which the chronology is a key issue. To test the applicability of optically stimulated luminescence (OSL) dating methods to Holocene lake sediments and to evaluate the hard water reservoir effect of 14C dating in arid northern China, 12 OSL samples and 12 radiocarbon samples were dated. These samples were from an 8 m long lacustrine section (Qingtu Lake, QTL) in the Zhuyeze Palaeolake in arid northern China. Tests of luminescence characteristics (preheat temperature, laboratory dose recovery, OSL decay and growth curve, and equivalent doses distribution) confirm that the OSL signal of silt-sized quartz (38–63 μm) from the QTL section was fully reset before burial, and that OSL dating has considerable potential for improving the dating of Holocene lake sediments in the arid land of northern China, especially in those cases where there is a significant hard water ‘old carbon’ problem for 14C dates. The apparent agreement between OSL and 14C dating for QTL section suggests that the hard water reservoir effect of 14C samples in the study area is much smaller than that in other lakes in northern China, which is also supported by analyses on two 14C samples using different dating materials for each of the two individual samples.