Geochemical Characteristics And Genesis Of The Lower Cambrian Black Rock Series In Qujing Area, Yunnan Province

Southern China is widely distributed by Early Cambrian black rock series-rich organic matter is an important carrier with PGE, Au, Ag, Ni, Mo, V, etc. The output of large Ni-Mo-PGE Deposits, V-Cu, U deposits, phosphoresce beds and barite deposits, etc. Analysis of large metal, non-metallic mineral deposit and black rock series has become one of the hottest areas of research today to academia. Under the Qujing area Cambrian black rock series developed extensively, but do not get people’s attention. In this paper, sedimentology, sequence stratigraphy, depositional areas of Qujing early phase of Early Cambrian sedimentary sequence is studied, established under the early Cambrian sedimentary fancies model, summarize the lithofacies paleogeography. By Element Geochemistry studies in identifying material composition of black rock series, explores the environment, the establishment of a black rock series nickel molybdenum polymetallic ore genetic model in this area.1. By outcrop observations, the measured profile and drilling catalog, indoor rock analysis, combined with previous studies to determine the lithological sequence Qujing area under Cambrian black rock series, namely carbonaceous siltstone, carbonaceous shale siltstone, carbonaceous shale, mudstone black molybdenum nickel mineralization.2. The thesis think Qujing area early Cambrian sedimentary environment overall is littoral- bathyal, established its sedimentary facies model, summarizes the various sedimentary microfacies characteristics. The study showed that the formation of black rock series of Qujing area controlled by regional depositional environment.3. Through the major elements, trace elements and geochemical characteristics of REE showed terrigenous sediments mainly supplemented jet deposition, and a large number of biological deposition participation, mainly for low-energy depositional environment, hypoxia reduction environment, rich in organic matter content.4. In a comprehensive analysis of sedimentary digenesis, depositional environment and mineralization characteristics, combined with the mineralization characteristics in the study area Cambrian black rock series of molybdenum metal nickel more established black rock series nickel molybdenum polymetallic ore genetic model:the study area located southeast margin of Yangtze block, and its tectonic activity, volcanic activity and are more intense magnetism. Cambrian period, Kangdian ancient land is the source material supply area, clastic sediments, the east and the northeast margin mainly littoral-bathyal depositional environment. At that time, algae, fungi and plankton flourish, his body rot after absorbing large amounts of oxygen, resulting in anoxic seawater, forming a large number of organic-rich black rock series. Due to tectonic activity, volcanic activity strongly in the study area developed deep faults, along deep faults ancient jet mouth, from deep crustal magma activity brought Mo-Ni and other metal elements, magma deep carry bottom ultrabasic. The upper mafic useful elements Chung, together with sea hydrothermal ore-forming and under the influence of bottom currents, upwelling, such as seawater, in stagnation, reduction of shallow water reducing environment is organic matter and algae, plankton adsorption, precipitation mineralization.