地磁梯度测量及其在金属矿勘查中的试验——以拉依克勒克铜铁矿为例  

Geomagnetic gradient exploration and its test in metal deposits: a case study of the Layikeleke copper-iron deposit

作　　者：王昊 严加永[1,2] 孟贵祥[1,2] 吕庆田 王栩[1,2,3] WANG Hao;YAN Jia-Yong;MENG Gui-Xiang;LU Qing-Tian;WANG Xv(Chinese Academy of Geological Sciences,Beijing 100037,China;China Deep Exploration Center,China Geological Survey&Chinese Academy of Geological Sciences,Beijing 100037,China;School of Geophysics and Information Technology,China University of Geosciences,Beijing 100083,Chi?na)

机构地区：[1]中国地质科学院,北京100037 [2]中国地质调查局中国地质科学院地球深部探测中心,北京100037 [3]中国地质大学(北京)地球物理与信息技术学院,北京100083

出　　处：《物探与化探》2019年第6期1173-1181,共9页Geophysical and Geochemical Exploration

基　　金：国家自然科学基金项目(41574133);国家重点基础研究发展计划项目(2018YFC0604002);新疆地勘基金项目(A11-3-XJ4);中国地质调查局“钦杭结合带及邻区深部地质调查”和“武陵山—江南造山带中段深部地质调查”项目(DD20160007、DD20190071)

摘　　要：随着超高灵敏度和高精度磁力仪的技术进步,磁梯度测量也成为可能,并在非爆炸物探测等工程物探领域中得到了广泛应用。为了解实测磁梯度与计算磁梯度的差异及其在金属矿上的应用效果,在新疆东准噶尔拉依克勒克铜铁矿开展了1∶5000比例尺的磁梯度测量试验。对比了实测磁梯度与计算磁梯度的异同,发现实测磁梯度与计算磁梯度两者宏观趋势基本一致,但在异常细节上存在差异;在点距和线距不相等的情况下,计算磁梯度测线效果明显,在特定方向磁异常有沿测线方向拉长的现象;不同强度异常区计算梯度与实测梯度存在差异,特别是垂向梯度差异最大。实测磁梯度对埋藏浅异常大的地质体有相对明显的探测优势,并且可以获得更多的地质体边界和位置信息,对于低缓异常,由于地形等条件限制了探头之间的距离,获得磁异常较弱。结合拉伊克勒克磁铁矿勘探成果分析,认为实测磁梯度对局部异常探测比较灵敏,对围岩是有磁性的火山岩等矿床,地磁梯度测量有利于圈定磁性体边界。实测磁梯度的二维和三维矢量图也可以区分异常体的性质等,为找矿预测提供指示。With the progress in the study of ultra?high sensitivity and high precision magnetometers,magnetic gradient measurement has become possible,and is currently widely used in the field of engineering geophysical explorations such as non?explosives detection.In order to understand the difference between the measured magnetic gradient and the calculated magnetic gradient and its application effect on the metal ore,the authors carried out a 1∶5000 magnetic gradient measurement test in the Laikluck copper?iron deposit in East Junggar,Xinjiang,The authors compared the difference and similarity between the measured magnetic gradient and the calculated magnetic gradient.It is found that the macroscopic trend of the measured magnetic gradient and the calculated magnetic gradient are ba?sically the same,but there are differences in the anomaly details;when the point distance and the line spacing are not equal,the cal?culation of the magnetic gradient line is effective.In a certain direction,the magnetic anomaly has a tendency of lengthening along the direction of the line;the difference between the calculated gradient and the measured gradient in different intensity anomalies is the lar?gest,especially the vertical gradient.The measured magnetic gradient has a relatively obvious detection advantage for burial shallow a?nomalous geological bodies,and can obtain more geological body information.For low?relief anomalies,the distance between the probes is limited due to the topographical conditions,and the magnetic anomalies are weak.Combined with the analysis of the exploration re?sults of the Laikluck magnetite,it is considered that the measured magnetic gradient is sensitive to local anomaly detection,and the surrounding rocks are magnetic deposit such as volcanic rock.The geomagnetic gradient measurement is beneficial to delineating the magnetic boundary.The two?dimensional and three-dimensional vector of the measured magnetic gradient can also distinguish the na?ture of the anomaly and provide an indication for the prospe

关 键 词：磁法勘探 实测磁梯度 计算磁梯度 拉依克勒克铜铁矿 

分 类 号：P631[天文地球—地质矿产勘探]