Construction of a Deep Prospecting Model for Baiyinchang Xiaotieshan VHMS-Type Deposit Based on Wide-Field Coded-Source Electromagnetic Sounding Method
Guo Xiaogang
Dai Shuang
Luo Weibin
Guo Weiliang
Liao Yongfeng
Han Feng
Zhou Xiaohong
Wang Qin
Han Pan
Abstract：Prospecting for ore bodies in the deep and peripheral zones remains pivotal for breakthroughs in the volcanic-hosted massive sulfide(VHMS)-type Cu-polymetallic ore field of the Baiyinchang district.However,conventional geophysical methods have limitations in application due to shallow electromagnetic interference and insufficient resolution at depth.To address these challenges,this study innovatively integrates the Wide-Field Electromagnetic Method(WFEM)and Coded Source Electromagnetic Sounding(CSES)for deep exploration in the Xiaotieshan mining area.The results demonstrate that the resistivity of ferromanganese siliceous rocks and lead-zinc ores is below 100 Ω·m,while the ore-hosting Quartz-keratophyre tuffs exhibit a low resistivity(mean value:191 Ω·m).In contrast,the subquartz-keratophyre,as the main ore-controlling geological unit,shows significantly higher resistivity(mean value:1 976 Ω·m),revealing quantifiable electrical contrasts.Subvolcanic intrusions are characterized by dendritic high-resistivity anomalies(>1 500 Ω·m),with favorable prospecting targets identified in transitional zones(<400 Ω·m),deep extensions of known ore bodies,and low-resistivity anomalies atop high-resistivity zones.The combined application of two geophysical methods in complex stratigraphic regions of volcanic rocks demonstrates synergistic effects:the wide-field electromagnetic method effectively reveals the electrical structure of volcanic basement and deep-seated high-resistivity rock masses,while the encoded-source electromagnetic sounding method enables high-precision delineation of middle-shallow low-resistivity mineralized zones.Based on integrating geophysical anomalies and metallogenic dynamics,a composite genetic model-termed"volcanic structure-hydrothermal convection-tectonic activation"-is proposed to elucidate the multi-stage mineralization processes.A geological-geophysical"magma-tectonic-alteration synergistic prospecting model"is established,delineating four prospective targets.These findings provide critical constraints for drill hole verification and offer scientific guidance for deep-peripheral exploration in the Baiyinchang ore field and regional analog studies.
Keywords：Xiaotieshan deposit of the Baiyinchang districtVHMS-type copper polymetallic depositwide-field electromagnetic methodcoded source electromagnetic sounding methodprospecting modeldeep prospectingmineralsengineering geology
Publication Date：2025-11-30
Online Publishing Date：2025-12-15(First online date of this platform, not the publication date of the document)
Pages：18( 4243-4260 )