Reworking effects in the Holocene Zhuye Lake sediments: A case study by pollen concentrates AMS 14C dating

Abstract

Transported by wind and water, the relatively old sediments can deposit in the terminal lake of an inland drainage basin. The reworking effect can affect the lake sediments 14C dating and explanations for proxies. The Zhuye Lake is the terminal lake of the Shiyang River Basin. Previous studies indicated that sediments in different locations of the lake basin showed different climatic change patterns. And then, some radiocarbon dates were inverted for some Late Pleistocene sections. Whether this phenomenon is related with the reworking effect? The pollen concentrates 14C dating can avoid the reservoir effect, which is an ideal method for studying the reworking effect. In this study, we used the pollen concentrates as dating materials and dated five Holocene sections in the Zhuye Lake Basin. Based on the 14C dates comparison between the pollen concentrates, organic matter, and shells, the pollen concentrates dates are relatively older than other dating materials. Based on the result, the reworking effect worked in the Zhuye Lake Basin during the Holocene; however, in different locations of the lake basin the reworking effects were in different levels. Furthermore, the Holocene lacustrine deposits were formed mostly during the early and middle Holocene. This study provided clues for reworking effect studies of other lakes in arid China.