宁芜火山岩盆地及邻区上地壳电性结构研究  

The study of upper crust electrical structure in Ningwu and adjacent area

作　　者：张昆[1,2] 严加永[1] 吕庆田[3] 赵金花[1] 

机构地区：[1]中国地质科学院矿产资源研究所,国土资源部成矿作用和资源评价重点实验室,北京100037 [2]中国科学院地质与地球物理研究所,北京100029 [3]中国地质科学院地球物理地球化学勘查研究所,河北廊坊065000

出　　处：《地球物理学报》2015年第12期4505-4521,共17页Chinese Journal of Geophysics

基　　金：“十二五”国家科技支撑计划项目“宁芜矿集区深部控矿结构3D探测与深部勘查技术集成与示范(2011BAB04B01)”(2011-2015);国家深部探测专项第三项目(SinoProb-03);山东三山岛北东浅海区深部矿产远景调查(12120114053301)(2014-2015),地质矿产勘查标准的研制与修订--制定《深部矿产远景调查技术要求(试行)项目联合资助

摘　　要：为了较全面、客观地认识宁芜矿集区上地壳电性结构,研究"玢岩铁矿"成矿规律与深部地球物理、地质结构的对应关系,为探索深部"第二找矿空间"提供物性参数,我们完成了6条宽频大地电磁测深剖面.通过分析各剖面电性成像结果,讨论了"长江断裂带"与矿集区成矿的关系,并且认为围岩、岩浆及其上侵通道是区内矿床的控矿因素.此外,结合姑山铁矿床的位置以及铁矿床成矿规律判断宁芜火山岩盆地南部低阻条带为矿集区姑山火山-岩浆旋回的岩浆(导矿)通道,而盆地东部邻区的倾斜"叠瓦状"电性特征说明该区在经历了印支期褶皱构造运动后发育了逆冲推覆构造.In order to understand the deep electrical structure of upper crust more comprehensively and objectively in Ningwu ore district,and study the corresponding relationship between metallogenic regularity of＂Porphyrite iron ore＂and geophysics and geology structure,and provide physical parameters for the exploration of deep ＂second prospecting space＂,we completed 6broadband magnetotelluric profiles in Ningwu ore district and its southern region.Data of 280 stations were used in the process,inversion and interpretation.Several new technology improved by us were used in data process such as data fitting denoise and joint static shift correction methods.Then we find that the main structural direction is northeast and northwest by the analysis of strike direction,so the inversion models of line 1,3,4,5reflect the NE-trending structure,and models of line 2and 6reflect NW.Then we discuss the relationship of＂Yangtze River Fault＂and ore-forming.We consider thatYangtze River Fault belt is existed and combined by several deep and shallow faults.The surrounding rock,magma and intrusion channels are the controlling factors in the region deposit,and the tectonic movement process of Ma＇anshan-Fanchang area is deduced by their relationship reflected in inversion models.We estimate that the low resistivity band in south Ningwu basin was the magma channel for Gushan volcano-magmatic cycle combining with the location and metallogenic regularity of Gushan iron ore.The inclined＂imbricated＂structure shows that thrust nappe structure was developed after the fold tectonic movement in Indosinian.And the high resistivity anomaly bodies and low resistivity layers in deep underground of Ningwu Basin are the electrical evidence for the＂Multi story building＂metallogenic regularity theory.

关 键 词：宁芜火山岩盆地 宽频大地电磁测深 上地壳 电性结构 

分 类 号：P313[天文地球—固体地球物理学] P631[天文地球—地球物理学]