摘要
文章以在长江铀矿田开展的宽频大地电磁探测与井中瞬变电磁测量为例,论述了该方法组合在花岗岩型深部隐伏铀矿勘查中的应用效果。研究区主要控矿要素为断裂构造、蚀变和不同类型的岩性界面,前两者由于岩石完整度、黏土和导电矿物含量等与围岩不同而表现出相对的低电阻率特征,故利用宽频大地电磁对低阻体的敏感性识别了探测剖面上的断裂构造,圈定了平距1320~1730 m范围为铀成矿有利部位。在上述有利部位实施的GUSD1科学深孔,钻遇多层铀矿体,实现了深部铀矿找矿突破。为进一步利用钻孔深度挖掘地质信息,开展了针对GUSD1的井中瞬变电磁实测,据此推测了第二、三、四铀矿体分别向SSE、SEE、SEE方向延伸,同时新发现井旁良导电地质体1处,推测为井旁破碎带。宽频大地电磁与井中瞬变电磁在长江铀矿田的综合应用,证明了上述两种方法在花岗岩型深部隐伏铀矿勘查中的有效性与适用性。同时,建立了一种先由宽频大地电磁基于断裂、蚀变体的探测来圈定铀成矿有利部位指导布钻,再在实施的钻孔中利用井中瞬变电磁实现就矿找矿、由地面到深孔的花岗岩型深部隐伏铀矿电磁法勘查模式,可为后续相同应用场景的花岗岩、火山岩型铀矿勘查提供借鉴。
The Broadband Magnetotellurics Detection(BMT)and Borehole Transient Electromagnetic Method(BHTEM)measurement carried out in Changjiang uranium ore field were used as an example to show the application effect in the exploration of deep concealed granite type uranium deposit in this paper.The main ore controlling elements in the research area are fault structures,alteration,and lithological interfaces of different types rocks.The first two elements show relatively low electrical resistivity characteristics due to differences in rock integrity,clay and conductive mineral content compared to the surrounding rocks.Therefore,the sensitivity of BMT to low resistivity bodies was used to identify the fault structures on the detection profile,and the favorable location for uranium mineralization was delineated as a horizontal distance of 1320~1730 m.As a result,the GUSD1 scientific deep hole drilling implemented in the favorable areas mentioned above has revealed multiple layers of uranium mineralization,making a breakthrough in deep uranium exploration.In order to further utilize the drilling to excavate geological information,BHTEM measurements were carried out in the borehole GUSD1.Based on the outcome,the second,third,and fourth uranium ore bodies were inferred extending along the SSE,SEE,and SEE directions.At the same time,a good conductive geological body was newly discovered beside the borehole,which was inferred to be a fracture zone.The successful application of BMT and BHTEM in Changjiang uranium ore field has proved the effectiveness and applicability of the methods in the exploration of deep concealed granite type uranium deposits,and established a deep concealed granite type uranium exploration model using electromagnetic method from ground to boreholes,which use BMT first to detect the fault and alteration for the delineation of favorable uranium mineralization and the position of drilling,and then use BHTEM to searching uranium orebody depth and direction in borehole.This study also provided a reference for the exploration of granite and volcanic rock type uranium deposits in the same application scenarios.
作者
段书新
刘祜
陈聪
汪硕
DUAN Shuxin;LIU Hu;CHEN Cong;WANG Shuo(Beijing Research Institute of Uranium Geology,Beijing 100029,China)
出处
《铀矿地质》
2025年第4期707-723,共17页
Uranium Geology
基金
核技术研发项目“诸广重点地区地球物理与成矿信息探测技术研究”(编号:H2301-2-2)资助。
作者简介
第一作者:段书新(1987-),男,2012年毕业于中国地质大学(北京),获硕士学位,高级工程师,主要从事电磁法勘探研究与应用。E-mail:duanshuxin@briug.cn。
