北天山七角井南部石英斑岩发育特征及其找矿意义:来自综合物探测量的证据  

Development Characteristics of Quartz Porphyry and Its Prospecting Significance Which in the South of Qijiaojing, North Tianshan:Evidence from Comprehensive Geophysical Survey

作　　者：祁程[1,2,3] 何昕欣 艾虎 杨明[1,3] 汪来 QI Cheng;HE Xin-xin;AI Hu;YANG Ming;WANG Lai(Airborne Survey and Remote Sensing Center of Nuclear Industry,Shijiazhuang 050002,China;Key Laboratory for Geophysical Exploration Technology of Uranium Resource,CNNC,Shijiazhuang 050002,China;Key Laboratory of Airborne Detection and Remote Sensing Technology of Hebei,Shijiazhuang 050002,China)

机构地区：[1]核工业航测遥感中心,石家庄050002 [2]中核集团铀资源地球物理勘查技术重点实验室,石家庄050002 [3]河北省航空探测与遥感技术重点实验室,石家庄050002

出　　处：《科学技术与工程》2022年第35期15494-15505,共12页Science Technology and Engineering

基　　金：中央财政铀矿地质勘查项目(201219)。

摘　　要：北天山七角井南部地区位于北天山造山带博格达-哈尔里克裂谷南缘,是准噶尔-巴尔喀什火山岩型铀成矿带的重要组成部分。铀矿化主要赋存于受北东向构造控制的晚二叠世石英斑岩裂隙带中,或者石英斑岩外接触带砂岩、凝灰质砂岩中,以及断裂构造破碎蚀变带中,因此,厘定石英斑岩空间展布特征对扩大深部矿化规模具有重要意义。选择音频大地电磁测量与地面高精度磁测相结合的物探方法,对该地区的石英斑岩进行探测,采用Rubust阻抗估算技术、二维有限元差分法的电磁数值模拟技术、非线性共轭梯度法的电磁反演技术、2.5维地磁异常反演技术等进行综合研究,结合地质背景,大致查明了石英斑岩深部发育情况。研究结果表明:晚二叠世石英斑岩沿北东向断裂构造破碎带呈裂隙式侵入,呈狭长线性带状分布,自西向东,石英斑岩深部规模呈下窄上宽→下宽上窄变化的形态。受北西向构造挤压抬升作用影响较大,石英斑岩被抬升并剥蚀,西部岩体破碎更强烈。结合钻孔验证情况,分析推断铀成矿有利区有2片,为下一步铀矿勘查工作提供了依据。The southern Qijiaojing area of North Tianshan is located in the southern margin of Bogda-Harlik rift in North Tianshan orogenic belt, which is an important part of Junggar-Balkashi volcanic type uranium metallogenic belt. Uranium mineralization mainly occurs in the fracture zone of Late Permian quartz porphyry controlled by NE trending structure, or in the sandstone and tuffaceous sandstone in the outer contact zone of quartz porphyry, as well as in the fracture alteration zone of fault structure. Therefore, it is of great significance to determine the spatial distribution characteristics of quartz porphyry for expanding the scale of deep mineralization. The geophysical method combining Audio Magnetotelluric Method and high precision magnetic survey on the ground was selected to detect quartz porphyry in this area. The comprehensive research was carried out by using Rubust impedance estimation technology, electromagnetic numerical simulation technology of 2D finite element difference method, electromagnetic inversion technology of nonlinear conjugate gradient method, inversion technology of 2.5D geomagnetic anomaly, and combining with geological background, the formation structure and the deep development of granite porphyry were basically found out. The results show that the Late Permian quartz porphyry is fractured and distributed in a narrow linear band along the Northeast fault structure fracture zone. From west to East, the deep scale of quartz porphyry changes from narrow to lower width and narrow in depth. The quartz porphyry is uplifted and denuded, and the western rock mass is broken more strongly. Based on the verification of drilling, two favorable areas of uranium mineralization are inferred, which provides the basis for the next uranium exploration.

关 键 词：石英斑岩 火山岩型铀矿 综合物探测量 正反演 天山造山带 

分 类 号：P631[天文地球—地质矿产勘探]