Determination And Distribution Of Trace Antimony In The Global Core Samples In Qaidam Basin

A series of salt lake distributes in Qaidam Basin .Qarhan Salt Lake is located in the central Qaidam Basin. It is the largest salt lake in China, and also is one of the world's most famous inland lake. The core sediments record the earth's geological information. The research on the vertical distribution of antimony in Qarhan Salt lake would not only demonstrate the background of the region's history for antimony migration but also reflect the changes in the geological process and fluctuations in palaeoclimate information. To reveal the vertical distribution of trace antimony is essential for understanding the elements cycle of antimony in the global, environmental assessment and ecological effect. Under the joint financial supports from the National Natural Science Foundation of China (Grants 20836009 and 40773045), the vertical distributions of antimony in Qarhan Salt Lake was carried out as following.The research contents include:â‘ test the sensitive antimony analysis method for high saline brines;â‘¡total iron (TFe), total manganese (TMn), total antimony (TSb), water soluble antimony (Sb-H₂O), antimony absorbed onto oxyhydroxides of iron and manganese (Sb-oxal), associated to organic matters (Sb-H₂O₂), and antimony existed in the crystallized sulfides (Sb-pyrite) were extrated by a sequential extracted procedures, and then were analyzed.Conclusions presented in this study can be summarized as follows:â‘ Hydride generation - atomic fluorescence spectrometry (HG-AFS) established by Deng (2001) for antimony analysis is suitable for high saline brines.â‘¡Total antimony content of different lithology are as follows: clay > silt >mealy sand containing salt > arenaceous salt with silt particles > salt containing mealy sand >pure salt particles. Salt does not have a significant effect on absorbing antimony.â‘¢In the Qarhan global core samples, total antimony in the deepth of 0～-10.00 m and -44.00～-48.00 m are low, -10.00～-44.00 m is inhomogeneous, -48.60～-103.15 m shows a great increase.â‘£The average concentration of different antimony species are as follows: Sb(pyrite) > Sb(oxal) > Sb(H₂O₂) > Sb(H₂O). Antimony mainly absorbed onto iron and manganese oxyhydroxides, crystallized sulfides. Sb(H₂O) and Sb(H₂O₂) are very low;⑤In Qarhan salt lake layer (0 m～-47.07 m), TSb is closely related to TFe and TMn. In the layer(-47.07 m～-103.15 m), TFe and TMn show little effect on TSb distributions.