The Swedish time scale: a potential calibration tool for the radiocarbon time scale during the Late Weichselian

Abstract

Describes the present state of the Swedish Time Scale (STS) and illustrates the application of this worldwide unique varve chronology for AMS radiocarbon measurements. The results are compared to other 14C-dated calendar-year chronologies: dendrochronology, laminated lake sediments and U/Th. The data set agrees with the oldest part of the dendrochronological calibration curve, and with AMS 14C-dated lake lamination data and U/Th on corals down to ca 12 ka calendar years BP. Further back in time, the AMS-dated part of the STS compares well with lake lamination chronologies and shows that the difference between 14C and calendar years decreases rapidly between 12 600 and 12 800 calendar years BP. Such a development seems to contrast with U/Th measurements on corals. Suggests that the cause for the divergence among three supposed calendar-year chronologies lies in the fact that the data points on the marine 14C-U/Th curve are more widely spaced in time than the tightly grouped set of terrestrial AMS 14C dates, and thus are not able to reflect short-term changes in atmospheric 14C.