Geochemical Compositions of Surface Sediment from Gobi Desert in Northern China and Its Sedimentary Significance
Gobi (desert pavement) occupies a large area of the China's mainland as one of the important desert landscapes in arid and semi-arid regions.Its unique composition and sedimentary characteristics have important significance to explain its provenances and generate process.But,there still exist some lack of systematic investigation of the geochemical features of different types of gobi sediments in China.In this paper,we analyzed the geochemical element compositions of different particle size sediments through sieving treatment.The results show that the characteristics of major element composition of surface sediment are similar from different gobi surfaces,but it shows slightly different between different grain size sediments.Compared with the average chemical composition of UCC,major elements except Si is consistent with the UCC in surface sediments from gobi,the rest of the main elements are in varying degrees showed enrichment and leaching characteristics.Trace elements variation between different grain sizes in two mainly kinds of gobi shows basically the same trends with the main elements.Surface sediment from gobi lack of effectively chemical weathering processes in the extreme arid climate conditions,basically at no or weak initial,intermediate stages of the continental chemical weathering process.Each grain size sediment have better inheritance relationship after erosion and weathering processes shows that gobi gravels underlying finegrained sedimentary layers are not exogenous handling precipitation,but formed through in situ weathering and pedogenesis of local rock fragments.
NETL
NSTL
万方数据
维普
