2011/01/01 by Yanhong Wu, Sumin Wang, Liping Zhou · 1 citation
Earth and Planetary Sciences · Environmental Science · #Geology and Paleoclimatology Research #Isotope Analysis in Ecology #Geological formations and processes
paper · pdf · doi:10.1017/s0033822200056617
Many factors may influence the radiocarbon age results of lacustrine sediments, among which the hardwater effect is particularly important. Daihai Lake is a closed lake located in the semi-arid region of Inner Mongolia, China. High concentrations of HCO 3 - and CO 3 2- and high pH values in the lake water imply that there is a hardwater effect when using bulk lacustrine sediment samples for 14 C dating. To correct the apparent 14 C age, we present a pilot study based on a series of 14 C ages of lake surface sediment, lake water, submerged aquatic plant ( Myriophyllum ), fish bone ( Cyprinus carpio ), and surface soil samples from and around Daihai Lake. Assuming that the relationship between the 14 C/ 12 C ratio of DIC and of atmospheric CO 2 was constant (at 0.816), the hardwater effect ages calculated for the past 8000 yr would have varied from 949 to 1788 yr. Together with the reservoir effect and soil organic matter input, the hardwater effect is a major factor causing changes in apparent age when using bulk organic matter for 14 C dating.