Authors: Xing Hu Liping Zhu Yong Wang Junbo Wang Ping Peng Qingfeng Ma Jianfang Hu Xiao Lin
Publish Date: 2014/03/27
Volume: 59, Issue: 24, Pages: 3022-3033
Abstract
The content and hydrogen isotope ratios of nalkanes extracted from recent lake surface sediments sampled from nine lakes in three different climate zones on the Southwestern Tibetan Plateau were analyzed Values were compared with nalkanes in plants from lake drainages and δD values of meteoric water lake water and mean annual precipitation The results showed that nC23 was predominantly derived from aquatic plants and nC27–nC33 from terrestrial higher plants The average carbon chain length of nC27–nC33 ACL27–33 was positively correlated with the mean annual precipitation δD values of the longchain nalkanes nC29 and nC31 of terrestrial origin varying between −214 ‰ and −169 ‰ and −226 ‰ and −185 ‰ respectively were inversely correlated with mean annual precipitation but in accordance with the average annual variations in δD OIPC δD values of nC31 were strongly related to the δD values of growing season meteoric water R 2 = 074 The large difference between δD values of nC23 of aquatic origin and nC31 an average of about 27 ‰ demonstrates the enrichment of the lake water δD compared to precipitation caused by strong evaporation in the semiarid–arid areas of the southwestern Tibetan Plateau Average value of varepsilon ntextC 2531/textp −95 ‰ is evidently higher than the value observed in European wet regions −128 ‰ besides varepsilon ntextC 31 about −116 ‰ is constant along the study transect SD = 9 which indicates that nC31 is a useful proxy for the environmentThis work was supported by a Major Program of the National Natural Science Foundation of China 41190082 the National Basic Research Program of China 2012CB956101 the Key Project of National Science Foundation of China 2012FY111400 and the Strategic Priority Research Program of Chinese Academy of Sciences XDB03030400
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