Influence of variation in precipitation on the δD values of terrestrial n-alkanes on the southern Tibetan Plateau

Abstract

A short lake sedimentary core and ice core were recovered from Lake Chen Co and Noijingangsang Glacier, respectively, in the Lake Yamdrok watershed of the southern Tibetan Plateau. Hydrogen isotope ratios of the ice core (δD ice) and δD values of terrestrial n-alkanes (δD wax) in the sediments showed a linear correlation (R 2 = 0. 41, P = 0. 047) over the past 80 years, indicating the effect of hydrogen isotope ratios of precipitation (δD p) on δD wax. However, apparent fractionation (ε wax-p) values of δD wax relative to δD ice increased with decreasing ice core accumulation (amount of precipitation; R 2 = 0.65, P = 0.0051), revealing that dry or wet climate variation had a significant impact on δD wax. Thus, precipitation amount and δD p are both important in determining δD wax. © 2012 The Author(s).