庐枞矿集区上地壳结构与变形：综合地球物理探测结果  

Upper Crustal Structure and Deformation of Lu-Zong Ore District: Constraints from Integrated Geophysical Data

作　　者：吕庆田[1] 刘振东[1] 汤井田[2] 吴明安[3] 严加永[1] 肖晓[2] 无 

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与资源评价重点实验室,北京100037 [2]中南大学地球科学与信息物理学院,长沙410083 [3]安徽省地质调查院,合肥230001 [4]SinoProbe-03-CJ项目组

出　　处：《地质学报》2014年第4期447-465,共19页Acta Geologica Sinica

基　　金：国家“深部探测技术与实验研究专项(SinoProbe)”第3项目“深部矿产资源立体探测技术及实验研究”第4课题(SinoProbe-0304);国家自然科学基金重点基金项目(编号:40930418)联合资助的成果

摘　　要：为揭示庐枞矿集区三维结构,深化对成矿作用的认识,为深部找矿提供更多信息,作者在庐枞矿集区实施了相互交叉的五条综合地球物理探测剖面。综合分析反射地震、MT及区域重磁数据,提出了矿集区上地壳结构、组成和构造变形的新认识。庐枞矿集区东西结构由"两坳一隆"组成,即西侧的潜山—孔城坳陷和东侧的庐枞火山岩盆地,二者之间以一隆起相隔;南北结构呈"南坳北隆"阶梯式台升,两个"台阶"断裂分别为汤家院—砖桥断裂、庐江—黄姑闸—铜陵拆离断层。庐枞火山岩盆地呈不对称"箕状",四周由向盆地倾斜的边界断裂围限。北、东边界断裂(BF2、LHTD)为深断裂,控制火山岩盆地的发展与演化。构造上,矿集区由"三横六纵"断裂系统构成,从北到南的"三横"依次为:庐江—黄姑闸—铜陵拆离断层、汤家院—砖桥断裂和仪津—陶家巷断裂(BF3);从西到东的"六纵"依次为:郯庐、滁河(CHF)、罗河—缺口、枞阳—黄屯、陶家湾—施家湾断裂和沿江断裂带。矿集区的形成与演化主体上受燕山陆内造山运动的影响,经历了中—晚侏罗世古太平洋板块NW向挤压和白垩纪的伸展。本文还取得了一系列新发现。确定了"沿江断裂"为逆冲断裂系,庐江—黄姑闸—铜陵断裂为向南倾斜的低缓拆离断层;新发现汤家院—砖桥断裂,该断裂将庐枞火山岩盆地和潜山—孔城坳陷分为南北两部分。庐枞火山岩东北部,发现保存相对完好的早、中侏罗世沉积盆地,盆地呈NWW—SEE走向,深达5.0km,认为它可能是印支期陆—陆碰撞后伸展阶段形成的盆地。In order to study the 3D structure of Lu-Zong ore-district,better understand the metallogenesis and provide in-depth information for deep mineral exploration,the author have finished five intersecting integrated geophysical profiles with total length of more than 300km.The survey methods include high resolution reflection seismic,magnetotelluric sounding（MT）and regional gravity.Some new discoveries were obtained regarding the upper crustal structure and deformation based on the integrated analysis of reflection seismic,MT,regional gravity and aeromagnetic data.In general,the Lu-Zong ore-district consist of “two depression one uplift”,e.g.,Qianshan-Kongcheng depression in the west and Lujiang-Zongyang volcanic basin in the east,a uplift exist just in between.The north south structure shows a northward step-like uplift,two step-like faults are WNW-ESE trending Tangjiayuan-Zhuanqiao fault and Lujiang-Huangguzha-Tongling fault respectively.Lu-Zong volcanic basin presents a non-symmetrical shape with four inward dipping boundary faults.The northern and eastern boundary faults （BF2 and LHTD）are deep faults,which control the development and evolution of the Lu-Zong volcanic basin.Tectonically, there are three WNW-ESE trending faults and six NE-SW trending faults cutting over the ore-district. From north to south,they are Lujiang-Huangguzha-Tongling detachement fault,Tangjiayuan-Zhuanqiao fault and Yijing-Taojiaxiang fault （BF3）;from the west to the east,six faults are Tan-Lu,Chihe,Luohe-Quekou,Zongyang-Huangtun,Taojiawan-Shijiawan and Along river fault.The formation and tectonic evolution of the ore-district was mainly affected by the Yanshanian intracontinental orogenic movement, and experienced the Middle^Late Jurassic contraction deformation due to the paleo-Pacific NW-trending subduction and Cretaceous extension deformation.Some other new findings regarding the nature of the faults were first obtained,e.g.,the Along river fault is a thrust fault in nature,Lujiang-Huangguzha-Tongling fault is a SW-dip

关 键 词：庐枞矿集区 反射地震 MT探测 上地壳结构 火山岩盆地 

分 类 号：P631[天文地球—地质矿产勘探]