|
|
|
题名
|
作者
|
年代
|
出处
|
被引量
|
| 1 | A two-step three dimensional marine magnetotelluric inversion method with considering rugged seafloor topography:Synthetic studies显示文摘Inversion of magnetotelluric(MT) responses has been used to explore the electrical conductivity distribution of the Earth’s interior. In three-dimensional(3-D) inversions, it is significant to use a good initial model, because final model obtained by most 3-D inversion methods is influenced by the initial model. Although uniform initial models are widely used in 3-D inversions, one-dimensional(1-D) initial models are alternatives, which could more appropriately represent the actual conductivity variations in the Earth’s interior. This study presents a two-step 3-D inversion method, especially for marine cases. This inversion method first concentrates on obtaining a 1-D initial model and then inverts for 3-D conductivity structures with it, in both of which the 3-D topography is carefully taken into consideration. This method was tested by synthetic models of different topography variations(depression-shaped, smoothly varying, channel-shaped and square-shaped plateau topography) and of heterogeneous layers with different checkerboard-type anomalies(sharp or smooth lateral conductivity variations) embedded in1-D model of depth-dependent conductivity. The comparisons were done about obtaining an initial model by the proposed method and that inverted from the corrected responses. The results of 3-D inversions by using the method of this study were also compared to that with different uniform initial models. Results of synthetic tests and comparisons were discussed by using directional information of newly introduced model-vector parameters. The performance and validity of this method was verified.It also revealed that some of the newly introduced model-vector parameters could be used to show the convergence of inversions and help to select inverse model. | Pengfei LIANG Qingyun DI Changmin FU Ruo WANG Qihui ZHEN Zhe YUN Jiagang ZHANG | 2023 | Science China Earth Sciences2023，66，4： | 0 |
| 2 | Summary of technology for a comprehensive geophysical exploration of gold mine in North China Craton显示文摘The North China Craton is the oldest continental block,and has suffered from large-scale lithospheric thinning and destruction,which in turn led to gold deposits in northern China.The decratonic gold deposits in the North China Craton became the most important gold deposits in China,and geophysical methods are key means to detect and discover gold deposits there.In this paper,based on the geological and petrophysical characteristics of the North China Craton,the geological model of the decratonic gold deposits is transformed into a geophysical model.At present,two methods of geophysical exploration of decratonic gold deposits are in use:rapid and efficient exploration on the scale of the ore concentration area,and large depth exploration on the scale of the deposit area.In detail,the airborne electromagnetic,magnetic and gravity methods are used to detect the shallow(1,500 m)anomaly area on the scale of the ore concentration area.Through the ground-controlled source electromagnetic and ground magnetotelluric methods,explorations for targets at significant depth(5,000 m)are carried out in the mining area.Then,taking the Liaodong ore concentration area as an example,geophysical methods are used to discover two prospecting areas around the Jianshanzi Fault in the Qingchengzi ore concentration area,Baiyun-Xiaotongjiapuzi deep prospecting area,and Qingchengzi deep prospecting area.Next,three prospecting areas are delineated around the Jixingou Fault in the Wulong mining area,Wulong deep prospecting area,Weishagou deep prospecting area,and Chang’an deep prospecting area.The anomalies in the ore concentration area and mining area are revealed by means of three-dimensional exploration methods,thereby providing technical support for the exploration of metal minerals such as decratonic gold deposits. | Qingyun DI Guoqiang XUE Da LEI Qingdong ZENG Changmin FU Zhiguo AN | 2021 | Science China Earth Sciences2021，64，9： | 0 |
| 3 | Insight into skywave theory and breakthrough applications in resource exploration显示文摘Skywave refers to the electromagnetic wave reflected or refracted from the ionosphere and propagated in the form of a guided wave between the ionosphere and the Earth’s surface.Since the skywave can propagate over large distances,it has been widely used in long-distance communication.This paper explores and demonstrates the feasibility of skywave for deep resource and energy exploration at depths of up to 10 km.Theoretical and technical advancements were accomplished in furthering skywave applications.A new solution method based on Green’s function has been developed to study skywave propagation in a fully coupled lithosphere-air-ionosphere full space model.For the first time,the model allows one to study skywave distribution characteristics in the lithosphere containing inhomogeneity such as ore deposits or oil and gas reservoirs.This model also lays a foundation for skywave data processing and interpretation.On a parallel line,we have developed a multi-channel,broadband,low-noise,portable data acquisition system suitable for receiving skywave signals.Using the skywave field excited by a high-power fixed source located in central China,actual field surveys have been carried out in some areas in China including the Biyang depression of Henan Province.The initial results appear encouraging—the interpreted resistivity models prove to be consistent with those of seismic exploration and known geological information,and the exploration cost is only~1/4 to 1/10 that of seismic surveys.These initial successful applications of the skywave theory lay a solid foundation for further verification of the new method. | Qingyun Di Changmin Fu Guoqiang Xue Miaoyue Wang Zhiguo An Ruo Wang Zhongxing Wang Da Lei Xianjun Zhuo | 2021 | National Science Review2021，8，12： | 0 |
您所在的机构暂未开通此部分的功能，请联系管理员