摘要
勘查区钒矿(化)体主要产出于下寒武统黑色岩系中,含钒岩系及钒矿体深部延伸受烟棵冲倒转向斜控制。为大致查明烟棵冲倒转向斜形态特征,推测含钒岩系或钒矿体深部延伸情况,布置了激电测深及音频大地电磁测深工作。经方法试验,激电测深法受勘查区含碳地层低阻屏蔽影响,无法开展,转用音频大电磁测深(Audiofrequency Magnetotelluric Method,AMT),利用其天然场源受低阻屏蔽影响较小的特性,采集到了正常的视电阻率/相位曲线,从而解决了因勘查区含炭地层影响导致人工场源电法无法开展的问题。利用自适应正则化算法(Adaptive Regularized Inversion Algorithm,ARIA)对AMT测深数据进行一维反演,建立初始模型,然后利用非线性共轭梯度算法(Non-Linear Congestion Control,NLCG)进行二维反演分析,初步查明了烟棵冲向斜轴线、核部、两翼、转折端等要素特征,推断了含矿岩系(向斜转折端)底部延伸情况,与钻孔资料比对,结果高度吻合。说明在新的物探方法和设备频出的当下,传统的如大地电磁(Magnetotelluric Method,MT)、音频大地电磁等天然源电磁法在地质勘查中依旧具有不可替代的优势。
The vanadium deposits(mineralization)in the exploration area mainly occurs in the black rock series of the Lower Cambrian,and the vanadium bearing rock series and the deep extension of the vanadium deposits are controlled by the Yankechong over turned anticline.In order to roughly determine the characteristics of the oblique shape of the Yankechong overthrust and speculate on the deep extension of the vanadium bearing rock series or vanadium ore body,induced polarization depth measurement and audio frequency magnetotelluric depth measurement were arranged.Through method testing,it was found that the time-domain induced polarization(TDIP)was unable to be carried out due to the low resistance shielding effect of carbon bearing strata in the exploration area.Instead,AMT was used to collect normal apparent resistivity/phase curves thanks to its characteristic of being less affected by low resistivity shielding from natural field source.This solved the problem caused by the influence of carbon bearing strata in the exploration area which prevented the use of artificial field source electrical method.Adaptive regularization algorithm(ARIA)was used to perform one-dimensional inversion on AMT sounding data to establish an initial model,and then two-dimensional inversion analysis was performed using nonlinear Conjugate gradient Method(NLCG),preliminarily identifying the essential characteristics of Yankechong such as oblique axis,core,wings,and turning point and inferring the extension of the bottom of the ore bearing rock series(oblique turning point).The results were highly consistent with the drilling data.In the current era when geophysical methods and equipment frequently emerge,traditional natural source electromagnetic methods such as MT and AMT still have irreplaceable advantages in geological exploration.
作者
程怀蒙
陈松
李贤军
王思桐
许欢
Cheng Huaimeng;Chen Song;Li Xianjun;Wang Sitong;Xu Huan(Hubei Geological Survey,Wuhan Hubei 430034,China;Hubei Key Laboratory of Resources and Eco-environmental Geology,Wuhan Hubei 430034,China;Six Geological Team of Hubei Geological Bureau,Xiaogan Hubei 432100,China)
出处
《工程地球物理学报》
2025年第3期406-415,共10页
Chinese Journal of Engineering Geophysics
基金
湖北省地质局部门预算项目(编号:KCDZ2023-11)。
关键词
钒矿(化)体
激电测深
低阻屏蔽
音频大地电磁
自适应正则化算法
非线性共轭梯度算法
vanadium ore body
time-domain induced polarization
low resistance shielding
audio-frequency magnetotelluric method
adaptive regularized inversion algorithm
non-linear congestion control
