Carbon isotopes in surface-sediment carbonates of modern Lake Qinghai (Qinghai-Tibet Plateau): Implications for lake evolution in arid areas
Carbon isotopes in surface-sediment carbonates of modern Lake Qinghai (Qinghai-Tibet Plateau): Implications for lake evolution in arid areas
复制标题
现代青海湖（青藏高原）表层沉积物碳酸盐中的碳同位素：对干旱地区湖泊演化的启示
DOI：
10.1016/j.chemgeo.2012.01.010
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发表时间：
2012-03-18
期刊：
影响因子：
3.9
通讯作者：
Xu, Liming
中科院分区：
文献类型：
--
作者：
Li, Xiangzhong;Liu, Weiguo;Xu, Liming
To further investigate the significance of carbon isotopes of lake carbonates in arid areas, we examined the carbon isotopic composition of ostracods, bulk carbonate, fine-grained carbonates, and associated water DIC (dissolved inorganic carbon) from Lake Qinghai and several small lakes and ponds surrounding Lake Qinghai. We obtained three major results. 1) The carbon isotopic compositions of ostracods, bulk carbonate, and fine-grained carbonates in the lakes and ponds are clearly correlated with water delta C-13(DIC) values, which vary with water salinity in the Lake Qinghai area. 2) The variation in the delta C-13(DIC) values of lake water is mainly controlled by CO2 exchanges between the atmosphere and lake waters in the Lake Qinghai area. 3) Ostracods, bulk carbonate and fine-grained carbonates show consistent trends of isotopic composition in the study area, and the differences in carbon isotopic composition between authigenic carbonates and ostracods may be explained by the differences in carbon isotopic composition between the DIC of surface water and that of the water near to the sediment-water interface as well as the 'vital offsets' of ostracods.Our results suggest that variations in the delta C-13 values of carbonates in Lake Qinghai and other lakes in this arid, high-altitude area are primarily controlled by the carbon-isotope ratios of the lake water DIC, which in turn are related to water salinity. Therefore, changes in carbonate delta C-13 values may be used to indirectly indicate changes in water salinity in the Lake Qinghai area. (C) 2012 Elsevier B.V. All rights reserved.
