音频大地电磁法对冀东某隐伏斑岩型钼多金属矿床指示作用研究OA
Audio magnetotelluric method:Implications for a concealed porphyry-hosted molybdenum-polymetallic deposit in eastern Hebei province
华北板块北缘冀东地区多金属矿床发育,多为与斑岩有关的多金属矿床,研究区位于承德北东部,是一典型的流纹斑岩型钼多金属矿床.该矿区地表出露隐爆角砾岩、流纹岩以及太古宇黑云角闪斜长片麻岩.根据对以往资料的分析研究,推测含矿的流纹斑岩位于隐爆角砾岩下部,埋深一般大于 500 m.利用传统的物探方法较难准确地定位深部钼多金属矿床的赋存位置.本文首次采用音频大地电磁法(AMT)在本区开展对隐伏斑岩型钼多金属矿床的定位试验研究,利用钼多金属矿低阻的特性,以电阻率 1 000 Ω·m 为异常上限,在研究区深部圈定了低阻异常范围,结合研究区地质成矿规律,试图根据电阻率低阻异常定位深部隐伏钼多金属矿床;根据推断钼多金属矿体的有利成矿位置,提出两个验证钻孔,经验证,在 01 号孔深部见到了厚 504 m 的工业品位钼矿体,在 02 号孔深部见到了厚 185 m 的钼矿体以及厚 200 m 的铅锌矿体,成功预测了钼多金属矿体位置.并利用 AMT 电阻率分布特征在本区构建了斑岩型钼多金属地球物理三维找矿模型,为定位隐伏深度较大的斑岩型钼多金属矿床提供了地球物理找矿新依据.
Polymetallic deposits,primarily porphyry-related polymetallic deposits,are hosted in eastern Hebei province in the northern margin of the North China Block.The study area,located in northeastern Chengde,is a typical rhyolite porphyry-hosted molybdenum-polymetallic deposit.Within this area,cryptoexplosive breccias,rhyolites,and the Archean biotite amphibole plagiogneisses are exposed on the surface.Based on previous data,it is speculated that the ore-bearing rhyolite porphyries occur beneath the cryptoexplosive brec-cias,with a burial depth generally exceeding 500 m.However,the deep-seated molybdenum-polymetallic deposits can barely be accu-rately located with traditional geophysical methods.Therefore,this paper used the audio magnetotelluric(AMT)method for the first time to locate the concealed porphyry-hosted molybdenum-polymetallic deposits in this area.Based on the low-resistivity characteristic of the molybdenum-polymetallic ores,and with 1 000 Ω·m as the upper limit,the range of low-resistivity anomalies was delineated in the deep strata of the study area.Then,combining the geological metallogenic patterns in the study area,this study tried to locate the deep-seated concealed molybdenum-polymetallic deposits based on low-resistivity anomalies.According to the speculated favorable metallogenic po-sitions of molybdenum polymetallic ore bodies,two boreholes were drilled for verification.An industrial-grade molybdenum ore body with a thickness of 504 m was discovered deep in No.1 borehole,while a molybdenum ore body with a thickness of 185 m and a lead-zinc ore body with a thickness of 200 m were discovered at depth in No.2 borehole,successfully predicting the positions.Moreover,based on the resistivity distribution revealed by AMT,a three-dimensional geophysical model was established for the exploration of por-phyry-hosted molybdenum-polymetallic deposits in this area.This model provides a new geophysical approach for locating deep-seated concealed porphyry-hosted molybdenum-polymetallic deposits.
杨磊;赵向奎;王晓东;张立剑;苗群峰;于浩;付荣钦
河北省地质矿产勘查开发局第四地质大队 冀北战略创新合作平台,河北 承德 067000河北省地质矿产勘查开发局第四地质大队 冀北战略创新合作平台,河北 承德 067000河北省地质矿产勘查开发局第四地质大队 冀北战略创新合作平台,河北 承德 067000河北省地质矿产勘查开发局第四地质大队 冀北战略创新合作平台,河北 承德 067000河北省地质矿产勘查开发局第四地质大队 冀北战略创新合作平台,河北 承德 067000河北省地质矿产勘查开发局第四地质大队 冀北战略创新合作平台,河北 承德 067000河北省地质矿产勘查开发局第四地质大队 冀北战略创新合作平台,河北 承德 067000
天文与地球科学
隐伏斑岩型钼多金属矿床音频大地电磁法(AMT)低阻异常三维找矿模型
concealed porphyry-hosted molybdenum-polymetallic depositaudio magnetotelluric(AMT)methodlow-resistivity anomalythree-dimensional model for mineral exploration
《物探与化探》 2026 (3)
458-468,11
河北省地质勘查基金项目冀北矿集区成矿机理研究项目(13000025P003294103391)
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