Exhalative Sedimentary Mineralization And Metallogenic Prediction In The Middle-Southern Segment Of The Da Hinggan Mountains

The middle-southern segment of the Da Hinggan Mountains is located at the supperimposed, composite and transformed portion where the Mesozoic NNE-stretching tectonic domain of the global Circum-Pacific belt strongly overprints the Paleozoic E-W-stretching tectonic domain of the Paleo-Asian Ocean. The early-stage research of copper-polymetallic deposits has been largely focused on magmatic metallogenic theory and model. Based on this fact, most of the ore deposits were regarded as epigenetic hydrothermal deposits in genetic connection with the Mesozoic magmatism. Based on the previous studies, this work is mainly aimed at the genesis and evolution of subaqueous exhalative mineralization by the study on the regional geology, strata geochemistry, petrology, mineralogy, petrochemistry, trace elements, isotopes and fluid inclusion, and some scientific results are obtained as follows:(1) It is a new opinion that the subaqueous exhalative mineralization has occured during the basin evolution at the Permian time in the study area, which is ignored and poorly understood, but might be as important as the hydrothermal mineralization connected with the Mesozoic magmatism.(2) Exhalites and the exhalative sedimentary mineralization has been the research hotspot in recent years among the geologists, which were largely focused on deep-sea basin, but scarcely on the shallow subaqueous environment. Especially in China, this research is limited to shallow subaqueous exhalites, but scarcely to mineral deposits. A new type shallow water exhalative mineralization is put forward to in this paper for the fist time. What's more, it is an innovative breakthrough to mineral deposits.(3) In the study area, the exhalative sedimentary deposits are divided into the Xiaobaliang VMS type deposit related to the deep-sea basin environment, and the Dajing SEDEX type deposit related to the lacustrine basin environment for the first time.(4) The geological setting of subaqueous exhalative mineralization was regarded as"Dashizhai Rift Basin"(DRB) for the first time, between the"Siberia Plate"(SP) and the"North China Plate"(NCP).(5) Guided by the mineralization theory and the theory of mathematieal geology, from the perspective of geological evolution, we studied the relationship of geology, physical exploration and geochemical exploration. The GIS-based weights of evidence modeling has been constructed, and forecast prospects have been delineated by using GIS techniques on the basis of the geological data. The results of research will provide a scientific basis for the further exploration and development of the mineral resources in the study area.