Study On Primary Halo Characteristics And Metallogenic Prediction Of Dongjianian Silver Deposit In Lingbao City,Henan Province

The Dongjianian silver deposit is the only large deposit found in the southern ore-forming belt of Xiaoqinling ore-gathering area,was discovered in 2016 by No.2Institute of Geological & Mineral Resources Survey of Henan.The Taihua group of Neoproterozoic,Gaoshanhe formation and Longjiayuan formation of Guandaokou group of Mid-proterozoic,Cambrian cinnabar cave formation and Mantou formation are mainly found in the area.Fault is the main tectonic form.The developed fault structure and multiple stages of magmatism are beneficial to metal mineralization.Through data analysis,field investigation,sample test analysis,primary halo geochemistry research,metallogenic rule summary and metallogenic prediction research,the following main achievements have been made:(1)The silver orebody is strictly controlled by the secondary structure F1 of the regional creek fault.The alteration zone of surrounding rock is clear,which can be divided into silver-lead mineralized sericite belt(inner belt),silicified cataclastic rock belt(middle belt)and potassium-altered granite belt(outer belt).The distribution range of the silver orebody and the inner alteration zone is approximately the same.Spatially,the orebody has an obvious trend of lateral volving in the direction of SE.The alteration zone of fault structure is the most important prospecting mark.(2)Through mathematical statistical analysis and research,it is determined that 9elements such as As,Sb,Ag,Au,Cu,Pb,Zn,Co and Mo are determined indicator elements.Among them,As and Sb are indicators of leading edge halo,Ag,Au,Cu,Pb and Zn are indicators of near-ore halo,and Co and Mo are indicators of tail halo.(3)According to the study and calculation of primary halo,the axial zonal sequence of M1-Imain orebody from shallow to deep is Co-Mo-Cu-Au-Sb-Zn-Pb-Ag-As,which shows the phenomenon of "reverse zonal",indicating that the orebody has multiple hydrothermal superposition in the formation process.Based on the study of the variation characteristics of primary halo geochemical parameters and the denudation degree of orebodies,it is considered that the orebodies will still have a large extension or blind orebodies in the deep,indicating that the main orebodies have a large prospecting potential in the deep.(4)Based on the ideal model of primary halo geochemistry of the main orebody and the summary of metallogenic regularities,a comprehensive geological prospecting model is established.The metallogenic prediction criteria were determined,and one level ?,? and ? metallogenic prediction target area was delineated,indicating the direction of deep prospecting.