科研之友
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摘要
For the purpose of revealing the deep tectonic background, the crustal structure framework, the spatial structure of magma system and the deep conductivity structure of Guichi ore concentrated area, two magnetotelluric (MT) sounding and seismic reflection profiles each about 60 km long have been conducted perpendicular to geologic strike. The underground conductivity structures extending from the shallow surface down to 10 km have been worked out after denoising and inversion. The regional crustal structure seismic imaging section is gained based on the tomographic static, prestack multi-domain noise attenuation, fine velocity analysis and prestack time migration. In combination with regional geological tectonic setting and the results of regional magnetic and gravity data, the inversion processing results of two comprehensive profiles are analyzed and explained. The formation of the tectonic reflection characteristics, characteristics of crust structure and the characteristics of Moho are founded through the work. The decollement surface between the cover and basement, the detachment surface between middle and lower crust and the depth and type of Moho are confirmed. It is found that the reflection characteristics of the earth's crust and the subduction are the traces of plate collision between the Cathaysia block and the Yangtze block occurred within Jinning period. The Gaotan fault is a fracture deep into the earth' s crust, the characteristics of magnetic and gravity, the electrical characteristics and the seismic reflection characteristics are different beside the fault, it is believed that the fault is the upwelling channel of the deep fluid. The mantle hydrothermal and magma intrusive into upper crust along the fracture and formed the batholith or rock mass along the strata and fractures. The polymetallic deposits in Guichi ore concentrated area are formed by the strong mineralization with surrounding rock.
- 出版日期2015-12
- 单位中国地质科学院矿产资源研究所
