Metallogenic Conditions And Metallogenic Prognosis Of The Ni-Mo Polymetallic Deposits In The Lower Cambrian Black Shale Series, Qujing, Yunnan Province

The black rock series of the lower Cambrian Qiongzhusi Formation widely distributed in the Yangtze platform of South China is rich in trace elements, rare earth elements(REE) and platinum group elements(PGE). The Ni-Mo polymetallic deposit is one of the important examples of the typical Ni-Mo deposit in black rock series which has been a hot spot of global studies.This paper takes the Ni-Mo polymetallic deposit in Qujing, Yunnan Province as the main research object, and the deposit is analyzed by comprehensive stratigraphy, sedimentology and geochemistry. The Ni-Mo polymetallic orebodies in the Lower Cambrian black shale series are distributed stably. The black rock series in Lower Cambrian is a necessary condition for the formation of Ni-Mo polymetallic deposits. The low energy, rich organic matter, and anoxic shallow water are the favorable sedimentary environment for the formation of Ni-Mo polymetallic deposits. Two layers of Ni-Mo ore are located in the Shiyantou section of the Lower Cambrian Qiongzhusi Formation. The hydrothermal sedimentary structure developed in the black rock series includes banded structure, network vein structure, nodular, lenticular structure and structures related with syndepositional deformation. There exists obvious enrichment of such sulfophilic elements as Ni、Mo、Cu、Zn、Pb、Cd、Sn、and Sb and lithophile element as Ba, W, Cs and U, while the high field intensity elements like Nb, Ta, Zr and Hf and large ion lithophile elements like Rb and Sr are evidently deficient. These characteristics show that the ore-forming material of nickel molybdenum polymetallic deposit is mainly from submarine hydrothermal exhalation.On the basis of the study on the mineralization, the metallogenetic rules and the metallogenic model are established. It is suggested that the main factors controlling the mineralization of Mo Ni polymetallic deposit are stratum and sedimentary facies. Through the research prospecting marks, this paper analyse the advantages of Ni-Mo polymetallic deposits vision area. The paper tells that Deze, Zhanyi and Huize Jiache are the best metallogenic favorable area. they Should be the focus of following prospecting work.