Near-zero Δ14C values at 32 kyr cal BP observed in the high-resolution 14C record from U-Th dated sediment of Lake Lisan

Abstract

A high-resolution atmospheric radiocarbon record has been obtained for the interval of 17-36 kyr from U/Th-dated aragonite sediment of Lake Lisan. Reservoir age corrections were applied with reservoir ages of 200, 1250, and 2000 yr, which correlate with the different water levels of the lake. The present 14C record for Lake Lisan shows near resemblance with that of Lake Suigetsu: both converge to the value of Δ14C ∼0‰ at 32 kyr cal BP. Both also show significant differences compared to other reported high-resolution 14C records (e.g. Iceland Sea, Cariaco basin, and Bahamas speleothem). This inconsistency should be addressed by re-assessment of the basic assumptions behind the determination of calendar ages of the various records.