The Application Study Of Magnetotelluric Method In Lead-zinc Polymetallic Deposits Of Southwestern Zhejiang

Lead-zinc polymetallic deposit are the important minerals of our country,butwith the exploration and development of mineral resources,the exploration ofsuperficial deposits are more and more difficult,Today focus is to carry outexploration work to the second space of the lead-zinc ore,dues to development of thedeep geological exploration theory lags behind and deep geochemical prediction isstill in its experimental stage,and because common geophysical methods are difficultto effectively detect deep geological structure,thus the magnetotelluric explorationthat is able to discern the deep geological fine structure will shoulder the historicalmission,so carring out magnetotelluric exploration research of the lead-zinc depositsis particularly important.Because first-line geophysical workers lack of insufficientknowledge to complex metallotectonics of lead-zinc ore for a long time and in-depthstudy to magnetotelluric anomaly characteristics of lead-zinc polymetallic depositscomplex metallotectonics system,resulting in the deficiency of complexmetallotectonics abnormal metallotectonics theory and practice understanding,somagnetotelluric exploration methods are difficult for a breakthrough in the lead-zincdeposits exploration.This paper chosed magnetotelluric response model of typicalstratabound lead-zinc polymetallic deposits metallotectonics for research,provided thecorresponding geological-magnetotelluric exploration model for exploratingstratabound lead-zinc polymetallic deposits,ore bodies and the similar ore deposits,orebodies and practical guide in the prospecting work on the theoretical analysis andpractical significance.Therefore,such research has theoretical guidance and practicalexploration significance.This paper described regional geological characteristics first,analysed the orebody and surrounding rock characteristics,described lead-zinc polymetallic depositsgeophysical characteristics of the study area,thought that lead-zinc body andsurrounding rock have the greatly electrical difference,and prepared the conditions formagnetotelluric exploration.Analysis of the geochemical characteristics of the studyarea,the abnormalitis of Au,Ag,Cu,Pb,Zn and other elements have NE directiondistribution in general,consistent with the geological mineralization.Analysis of thestudy area lead-zinc ore mineralization process and mineralization structural characteristics and the metallotectonics system was divided into basicmetallotectonics unit based on the general survey of geological,geophysical andgeochemical.This paper described the basic principles of magnetotelluric,acquisition,processing and inversion techniques.Constructed magnetotelluric model of the basicmetallotectonics unit based on the metallotectonics unit geological model,carried onresistivity numerical simulation and analysis,summed up the magnetotelluric responsecharacteristics of basic metallotectonics unit in the study area,based on thismagnetotelluric responses form was divided into four categories of abnormalities,theywere test tube-like abnormalities,intestinal-like abnormalities,the beadedabnormalities,and high impedance columnar abnormalities in the study area,detailedanalysed the typical characteristics of all kinds of abnormal response type.On thebasis of the summary of the various types abnormal response of the known profile andbasic metallotectonics unit,identified the ore body storage condition through theanalysis of fault,magmatic rocks and electrical sign layer,and as a basis outlined thestudy area three-dimensional metallotectonics characteristic of lead-zinc polymetallicmine.Thought that secondary folds of double fold structure was the tolerance structureof this metallogenic belt,deposit located in the end of the inverted wing of theoverturned anticline in the tendency of the north east.Based on previous magnetotelluric geological interpreted,analysed thecharacteristics of the Ge Ping metallotectonics belt on the basis of existinggeological,geophysical and geochemical data.So made the speculation to the ore bodieson the edge area,speculated that it existed concealed ore body in Huangba and Dragonand Tiger Pass side,so the soil geochemical and induced polarization soundingpre-validation work were carried out to them,and found the presence ofabnormalities.Negated the possibility of Huangba mineralization acording to theprinciple of a large ore body didn’t exited in the middle of metamorphic rocks,affirmedDragon and Tiger Pass anomaly belt.Then using magnetotelluric sounding evidencedthat,found that magnetotelluric data was consistent with soil geochemical and inducedpolarization data,concluded that Dragon and Tiger Pass anomaly belt was themineralization belt of metallogenic potential,and based on this,summarized thought ofthe magnetotelluric prospecting exploration method about lead-zinc deposits in thestudy area.Finally the paper makes summary to full text,and points out the researchinsufficiency as well as the direction and suggestions for further research.