Study On Ore-controlling Structure Of The Hadamengou Deposit In Inner Mongolia And Its Significance

The hadamengou gold deposit is located in the Wulashan-Daqingshan gold metallogenic belt,which is the only super large gold deposit in the metallogenic belt.Many scholars to the genesis of the hadamengou gold deposits in detail the research,mainly concentrated in the source of ore-forming fluid,source of ore-forming materials,metallogenic epoch,but research is limited to mining areas small scale in the tectonic system characteristics,and could not combine with the characteristics of large scale structure of regional and deposit genetic relationships,restricts the ore-controlling structure of the hadamengou gold field periphery prospecting.This paper is based on the achievement of previous research on the geological characteristic of mining areas,through field observation of fine structure,source of ore-forming materials analysis,isotopic dating method,combining with the geophysical,geochemical and remoting sensing data,a comprehensive analysis to discuss the forming time and material source and the regularity of migration,ore-controlling structure,on the basis of the structural ore-controlling model is put forward.The principal component analysis method was used to extract the remote sensing image information of Landsat8-OLI,ASTER and World View-3.By comparing the mineralization and alteration information of different images,a comprehensive get the hadamengou mining area two mineralization and alteration linear belts,which are basically consistent with mining areas the mountain front tectonic magmatic activity alteration zone and No.100 ore vein.Based on the controlled source audio-frequency magnetotelluric sounding perspective structural interpretation and drilling section,through the field observation fine structure characteristics,main tectonic framework in the mine for nearly east-west high angle imbricated thrust fault,tectonic movement direction from south east to north west,and the mining area most of the veins along the high angle imbricated thrust fault injection development.By analyzing the faults and boreholes of the spatial Fe isotopes,in order to the minging area exploration line 11 as the center,the?⁵⁶Fe values of pyrite in the F2 thrust fault and vein 100 gradually decrease to the east and west,and heavy isotopes enriched in Fe,indicating that the exploration line 11 is the center of ore-forming hydrothermal evolution.However,the?⁵⁶Fe value of magnetite in the F1 thrust fault is almost unchanged,and the light isotope enriched in Fe,and the calcite Sm-Nd isochron age is425±4.1 Ma,and consistent with the early thrust nappe strcuture of the Bainnaimiao gold depsoit.Combined with the large-scale regional thrust nappe tectonic era,based on the U-Pb chronology of the ore-forming protolites in the piedmont tectono-magmatic active alteration zone and the results of the Sm-Nd isochron age of the thrust fault calcite,which establish to the mining area ore-controlling structures model:In the early Caledonian stage,the early thrust fault was formed by the collision between the Bainaimiao island arc belt and the northern margin of the North China plate,and the fluid penetrated along the fault channel.Late yanshan stage,in response to the the closure of the Mongolian-Okhotsk ocean generate far field transfer and stress effect the characteristics,and gold mineralization was reactivated,iron melt-fluid flow along the high angle imbricated thrust fault channel rising positioning enrichment,and along the F1 thrust fault development No.100 vein is located at the exploration line 11,which is the center of the ore-forming hydrothermal,speculating to the south close to mountain front basin in the deep have batholith.