摘要
庐枞矿集区位于长江中下游成矿带,内赋有大型铁矿床、铜矿床及一系列中小型铅锌、铜、铜金矿床。为理解矿集区成岩成矿与深部结构的关系,通过5条大地电磁测深剖面,获得了庐枞矿集区及其邻区10km以浅的地电结构。地下电性分布清晰地反映了区域断裂位置、庐枞火山岩盆地的双层结构,指示了遭受多期构造运动的庐枞火山岩盆地外围基底出露区和大别造山带及其前陆地堑式凹陷盆地结构特征,划分了形成于不同时期、不同性质的地质构造单元,识别了火山盖层厚度和控制庐枞火山岩盆地范围的边界断裂。电性异常部位显示,与沙溪斑岩型铜矿具有成因联系的闪长岩体表现出亲造山带,可能为独立于火山岩盆地的具有不同演化路径的岩浆系统。通过3条北西—南东走向和2条北东—南西走向的剖面特征对比发现从浅至深北东-南西向构造在研究区内均占主导地位。根据一系列受断裂控制的北东-南西走向不同构造单元特征可以推演,在晚侏罗世挤压背景向早白垩纪伸展机制转变时,燕山期构造继承了印支期造山运动的前陆构造体系。
The Lujiang-Zongyang ore concentrated area is one of the most important ore concentrated areas in the middle and lower region of the Yangtze River metallogenic belt of China.Five magnetotelluric (MT ) sounding profiles have been conducted to understand the relationship between the metallogeny and petrogensis,and the deep conductivity structure.The underground conductivity structures extending from the shallow surface down to 10 kilometers clearly show the boundaries of the buried faults.It also shows the duple structures of the Luj iang-Zongyang volcanic basins as well as the characteristics of the Dabie orogeny,the foreland depressed basin and the exposed basements.The electrical resistivity anomalies show that the diorite porphyry hosted copper deposits in Shaxi area is the Dabei orogenic affinity which is different from the volcanic basin in magma evolutionary.The two-dimensional inversion results on the three NW-SE and the two NE-SW directed profiles shows that the NE-SW directed conductivity structures are dominant in this area.Inferred from the characteristics of tectonic units which controlled by NE-SW trending faults,we find that the Yanshanian structures was inherited from the Indosinian structures.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2014年第4期478-495,共18页
Acta Geologica Sinica
基金
国家科技专项“深部矿产资源立体探测技术与试验(SinoProbe-03-04)
国家自然科学基金青年基金(编号:41104071)资助
关键词
庐枞矿集区
火山岩盆地
大地电磁
二维反演
电性结构
构造格架
地质演化
Lujiang-Zongyang ore concentrated area
volcanic basin
magnetotellurics
2D inversion
conductivity structures
tectonic structures
geological evolution