Trace element geochemistry of Ni-Mo polymetallic deposits in early Cambrian black rock series from North Guizhou

• 1、School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023
• 2、School of Earth Sciences, East China University of Technology, Nanchang 330013

Abstract：The Ni-Mo polymetallic deposits hosted in early Cambrian black rock series in Southern China, is a typical example of this kind of deposit in the world, and its genesis and metallogenic process are complicated. The Huangjiawan mining area in Zunyi of Northern Guizhou is selected as a typical example. Element geochemistry is conducted to analyze the sedimentary environment.The results showed that the elements of Ni, Cd, Mo, Sb, V, Zn, W and Ba were especially enriched in the study area.Ba content is high, indicating that it is hydrothermal water deposition. Mo content is very high, indicating that it is anoxic reducing environment. High V/ (V+Ni), V/Cr, Ni/Co and δU value indicate that its sedimentary environment is anoxic environment. High U/Th indicates hydrothermal water deposition in this area. Therefore, both the ore bearing and non ore bearing black rock series are formed in the reduction environment, and are also affected by the hydrothermal water. Besides, the effect of the hydrothermal water reaches the maximum in the ore bearing strata . Meanwhile, it is considered that the enrichment of Ni may be related to the hydrothermal water.

Keywords： Sequence of the Ni-Mo black rock series Reducing environment Hydrothermal water effect The early Cambrian North Guizhou