On the Conductive Structure of Chinese Continental Lithosphere——Experiment on "Standard Monitoring Network" of Continental EM Parameters (SinoProbe-01)

The primary purpose of the Continental Crust Detection Project is to detect the composition, structure, and physical properties of the lithosphere. This includes the study of seismic wave velocity, density, magnetism, electrical conductivity, and radioactivity of the lithosphere. In recent decades, the study of lithospheric electrical structure has increasingly drawn the earth scientists' attention. The model of lithospheric electrical structure can be used to infer the geological structure and mineral composition of rocks in the deep earth. Information about the thermal structure of the earth's interior can also be obtained from the model to serve the study of earth's interior status, dynamic mechanism of the crust movement and other significant science subjects. Many developed countries has started the electrical structure detection of lithosphere since the 1970s. The United States started the EarthScope project at the year of 2004, and the magnetotelluric monitoring named USArray is one important part of the project. The USArray is set to observe the natural EM field on the continental scale, which will supply new constrains on the formation and evolution of the North American Continent. In China, though some significant advancement have been achieved from the study of the electrical structure of continental lithosphere, we only have some basic understanding about the general settings, and there is still a long way to go to reach the requirement for the study of continental dynamics. To understand the formation and evolution mechanism of Chinese continent, we need to study the 3-D geological structure, geothermal status and the rheological features of the Chinese continental lithosphere. All these objectives can not be achieved without a electrical structure with more details and accuracy. To accomplish the objective of establishing a 3-D dataset of EM parameters and modeling a electrical structure of the Chinese continental lithosphere, the experimental study of standard monitoring network of continental EM parameters (SinoProbe-01) was set within the project of SinoProbe. This experimental study aims to solve the key technical problems about the monitoring of MT array, make a detailed plan for MT observation, and supply example results. A 4°×4° regional MT array covering the whole country will be arranged in priority to build a controlling framework. Then, a 1°×1° MT array based on Northern China and Qinghai-Tibet Plateau will be laid out. The 3-D lithospheric electrical model of Northern China and Qinghai-Tibet Plateau will be built, and the model will be examined in different net degrees to determine a optimal plan for the whole network. This study is considered as the groundwork for the establishment of 3-D lithospheric electrical model, which will be instructive for the prediction of large-scaled metallization areas in China. The accomplishment of this project indicates more significant evidence for the study of tectonic feature and lithospheric structure of China. It will provide more constraints on the evaluation of solid mineral, oil and gas resources, and greatly complement the post-plate geotectonic theory. This study also denotes a new stage of the research on geotectonics and geophysics, and it will make significant contribution to the advancement of earth sciences and the sustainable development of China.