Numerical Simulation Of Hydrothermal Alteration And Mineralization Process In Anqing Copper Deposit

Based on the geological model and dynamic model,the evolution process ofmetallogenic dynamics can be reproduced by numerical simulation,and the formation of hydrothermal metallogenic system,mineralization alteration,dynamic characteristics,deposit location space and geochemical distribution characteristics can be quantitatively discussed.With the development of computer technology and numerical simulation technology,the current numerical simulation has gradually become a new method to solve the metallogenic process and mechanism of hydrothermal deposits.The Anqing copper deposit is a typical skarn-type deposit,which is located at the Anqing-Guichi ore cluster along the Middle and Lower Yangtze River Cu?Au?-Fe metallogenic Belt.A lot of research results have been obtained in the field of deposit science for Anqing copper deposit,but there is no quantitative understanding of the genesis of skarn alteration zoning and the influence of skarn diagenesis on the subsequent mineralization,and the research on hydrodynamic characteristics and their relationship with ore body morphology is still weak.Therefore,based on the coupled thermal flow chemical numerical simulation method,combined with geological facts and previous research results,this paper carried out numerical simulation work on the alteration and mineralization process of Anqing copper deposit,and obtained the following knowledge:?1?The spatial distribution characteristics of ore-forming materials carried by hydrothermal fluids are obviously different due to different driving forces of hydrothermal fluid migration.The simulation results show that the spatial distribution characteristics of ore-forming materials driven by temperature are more consistent with the actual ore body shape characteristics in the process of hydrothermal ore-forming in Anqing copper deposit.It shows that the formation process of Anqing copper deposit may be mainly driven by temperature,which mainly controls the enrichment process of ore-forming materials and the spatial occurrence of ore bodies.?2?The numerical simulation results of each mineralization stage of Anqing copper deposit show that the mineralization process is affected by the double intersection in the early skarn stage.Diopside is enriched on one side of the rock body,while garnet is enriched far away from the rock body.The formation of skarn increases the porosity of contact zone and makes more iron bearing hydrothermal fluid formation,which is conducive to the formation of later magnetite;in the magnetite stage,the Fe bearing hydrothermal fluid flows through the previously formed skarn and does not react and precipitate in the skarn.When it flows to the contact zone of carbonate rock,it reacts and precipitates to form a magnetite ore body,which causes magnet The enrichment of ore in the outer contact zone.At the same time,the precipitation process will block the pores in the skarn,reduce the permeability and porosity of the outer contact zone,and make the chalcopyrite mineralization far away from the contact zone in the quartz sulfide stage,forming mineral zoning.In the quartz sulfide stage,due to the deposition of magnetite in the contact zone between skarn and Dali rock,the porosity of skarn near the contact zone is significantly reduced,the migration speed of hydrothermal fluid is reduced,and the activity of Fe²⁺is reduced,so that the copper magnetite or copper skarn is formed on the side near the rock mass.Therefore,the main mineralization of Anqing copper deposit is copper iron mineralization in the outer contact zone and brass mineralization in the inner contact zone.