摘要
在山东玲珑断裂带深部找矿中,考虑断裂带处在地电干扰和地形变化复杂地段,且深部地质体产状变化较大,仅依据半空间地面物探方法很难摸清地质体的展布形态,盲目布设钻孔会造成找矿成本的提高。为精确反演深部矿体的边界范围、走向及倾向,提高钻孔见矿率,降低找矿成本,在山东玲珑断裂带地面、坑道采用立体物探技术,试验通过布设多条方位不同的地-坑、坑-坑和地-地纵横激电中梯剖面和双向三极测深剖面,进行了二维电法剖面反演。在地面-坑道激电测深方法中,地面-坑道供电,坑道测量探测深度与坑道深度呈正相关,反映了深部巷道底板以下电阻率和极化率的分布状况,可以实现深地探测目的。由于地面-坑道供电,坑道测量装置处在半空间和全空间两个部分,需要采用“镜像法”和地下倾斜偶极源电流场特征对其装置系数k值重新推导,以反映坑道空间岩矿体真实电阻率的变化。坑道中梯剖面异常与单向三极剖面异常、双向三极电测深反演结果对应较好。经钻探验证,矿体分布与物探推断高极化体基本一致,为快速准确布设深部钻孔提供资料。
The Linglong fault zone in Shandong lies in an area with complex terrain change and interference,and the occurrence of deep geologic bodies is highly variable,where prospecting deep ore bodies is underway.In this condition,it is difficult to clarify distribution of geological bodies based on the half-space surface geophysical methods,and blindly arranging boreholes will increase the cost of prospecting.To solve this problem,one possible approach is to probe the boundary range,trend and tendency of deep ore bodies by inversion of geophysical survey data.This work conducted an experiment for this goal using the ground-gallery IP sounding method in the Linglong fault zone.Many kinds of profiles in different directions were deployed,including ground-gallery,gallery-gallery,and ground-ground vertical and horizontal IP intermediate sounding profiles and bidirectional three-pole sounding profiles.Then 2D inversion was performed to the data from these profiles.In the ground-gallery IP sounding,the ground-tunnel power supply was adopted,and the depth of measurement is positively correlated with the depth of the gallery,reflecting the distribution of the resistivity and polarizability below the floor,which can achieve the purpose of deep exploration.Due to the ground-gallery power supply,the measuring device is located in half space and full space.So it needs to use the“mirror method”and the characteristics of the underground tilted dipole source current field to re-derive the device coefficient K value to reveal the real change of resistivity of rock in the gallery.The anomalies of the ladder profile in the gallery correspond well to the anomalies of the unidirectional tripolar profile and the inversion results of the bidirectional tripolar electrical sounding.Drilling verifies that the distribution of the ore bodies is largely consistent with the highly polarized bodies inferred by the geophysical survey,which provides data for the rapid and accurate deployment of deep boreholes.
作者
李忠平
李学军
LI Zhongping;LI Xuejun(Zhengyuan Geology&Exploration Institute of Shandong,China Metallurgy Geology Bureau,Jinan,Shandong 250014;Zhengyuan Geographic Information Group Co.,Ltd.,Beijing 101300)
出处
《地质与勘探》
CAS
CSCD
北大核心
2020年第4期783-791,共9页
Geology and Exploration
基金
全国危机矿山接替资源勘查项目(编号:200537015)资助。
关键词
地-坑激电
地-坑中梯测深
地-坑中梯装置系数
二维电法剖面反演
深部矿体
玲珑断裂带
山东
ground-gallery IP
ground-gallery intermediate gradient sounding
ground-gallery in termediate gradient device coefficient
two-dimensional electric method profile inversion
deep orebody
Linglong fault zone
Shandong Province
