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Distributional characteristics of trace elements (V,Co,Ni, Cu,Pb,Cr,Sr,Ra) have been examined in sedimentary rocks of various ages in Turfan, an intermountainous basin in Sinkiang Uighur Autonomous Region, northwestern China. Two major cycles are generally recognizable with respect to the variation in trace element contents during the geologic history from the Mesozoic through the Cenozoic, Within the first cycle, the concentrations of many trace elements except Sr and Ba were relatively high in the Early and Middle Jurassic (J1 and J2^1-J2^2 ), which were characterized by moist climate and a large amount of organic matter. But an opposite trend was observed as the climate became drier and organic matter depleted in Late Jurassic Period (J3). Within the second cycle, Sr and Ba decreased as opposed to the increase in many other trace elements in the Early Cretaceous while the reverse was true for the Tertiary. The distribution pattern of thrace elements is thought to be the result of the interaction among a variety of factors, such as the mode of migration of the elements,palaeoclimatology, palaeogeography, conditions of the water-medium, and ete. 相似文献
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