Lithium Isotopic Composition of the Dissolved and Suspended Loads of the Yangtze River,China
Received date: 2008-04-21
Revised date: 2008-07-14
Online published: 2008-09-10
A comprehensive understanding of lithium-isotope fractionation during terrestrial weathering is necessary in order to use lithium isotopes to trace chemical cycle and climatic changes. This study investigates lithium and lithium isotopic composition in the main tributaries and the main Yangtze river channel. The concentrations and isotopic compositions (δ7Li) of dissolved Li in the Yangtze river are in the range of 150n mol/L~4570n mol/L and in the range of +7.6‰~+28.1‰ respectively. Lithium isotopic compositions (δ7Li) of the suspended matter are relatively stable (-4.7‰~+0.7‰), and lighter than those of dissolved Li in the Yangtze river. Isotopic fractionation factors of between dissolved and suspended loads range from 0.977 to 0.992, and are corrected with the concentration and chemical composition of suspended matter in the Yangtze river main channel. This should reflect the adsorption of clay mineral and the degree of chemical weathering. The positive relationship between δ7Li and 1/Li for the dissolved load shows that the dissolved lithium probably has two main sources. One may be evaporites with some thermal spring, and another one may be silicates.
Key words： Lithium isotopes; Isotopic fractionation; Clay mineral; Chemical weathering; Origin.
LIU Congqiang , DING Hu1, , Chetelat Benjami , ZHAO Zhiqi , WANG Qilian . Lithium Isotopic Composition of the Dissolved and Suspended Loads of the Yangtze River,China[J]. Advances in Earth Science, 2008 , 23(9) : 952 -958 . DOI: 10.11867/j.issn.1001-8166.2008.09.0952
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