Geological Characteristics And Prospecting Direction Of Zhengyangshan Molybdenum Deposit In The Xiaoxing'an Mountains Metallogenic Belt

The Zhengyangshan Mo deposit is located in the east part of Xing?an-Mongolian Orogenic belt,northern segment of Lesser Xing?an Range-Zhangguangcai Range,northern margin of Songnen Massif.The study area experience multi-period and multi-stage magmatism,which provide favorable source of hydrothermal for mineralization,such as splitting and closure of Paleo-Asian Ocean,effection of Mongolia-Okhotsk Plate,subduction of Pacific Ocean.Basis on research work of previous study,combining existing geology,geochemistry,geophysics and remote sensing,we analysed ore-forming condition,prospecting indicator and ore genesis,and point out further prospecting direction.The understanding from this paper is as follow.The orebodies of Zhengyangshan Mo deposit is occurred within fractured porphyritic monzonite,which is developed in the surface.There are 11 industry Mo orebodied,2subordinated industry,8 low-grade Mo orebodies and 5 subordinated low-grade Mo orebodies.The type of ore is mainly sulfide ore,and ore minerals are composed of molybdenite,pyrite,magnetite and minor chalcopyrite.The wall rock alteration can be divided into three relative strong mineralized alteration.The intrazone is strong silicification,pyritization,magnetite,quartz-potash feldspathization.The mid-zone is silicification,pyritization,quartz-sericitization.The extrazone is argillization zone.Pyritization and propylitization are well developed in the stude area.The orebodies are occurredwithinstrongsilicification,pyritization,magnetite,quartz-potash feldspathization,secondly silicification,pyritzation,quartz-sericitization.The argillization zone without mineralization.The intrusive rocks in the mining area have low content of Cu,and all less than earth's crust abundance and variation of content is stabilized in different rocks.The most variation element is content of Mo,which is far more than earth's crust abundance,and the content of Mo is maximum in the strong silicification porphyritic monzonite(127.2×10^-6).It indicates that the monzonite provide ore-forming material to mineralization.Three groups of NW-trending faults is closely associated with mineralization.The intersection between derived EW-trending fault and three groups of NW-trending faults is beneficial for mineralization.Basis on research of geological characteristics of deposit,and ore-forming condition,we consider that the Zhengyangshan Mo deposit belongs to porphyry type deposit,and the prospecting direction is the orebodies discovered in the surface is the leading edge or branch of more big orebodise in the deep.The worked extent in the surface is low in the area,and there is a few trenches in the surface to control orebody,and prospecting potential in the deep is important.