Subdivision of tectonic units in China based on aeromagnetic data

This research is based on the compiled aeromagnetic map of China that almost covers whole China's continent and part of China's sea areas since 2011 and the magnetic features and fluctuation of magnetic basement reflected by these maps. Learning from subdivision idea of mainstream tectonic views, guiding by theories of plate tectonics and continental dynamics, and taking the tectonic features reflected by magnetic field as key points, in combination with gravity, remote sensing and geological data, the authors divided the tectonic setting of China into four levels. Eight first-order tectonic units include continental block domains and orogenic systems; thirty-two second order tectonic units include continental blocks, arc-basin systems and land mass; eighty-five third order tectonic units include basins, depression belts (areas), and uplift belts (areas); three hundred and thirty-two fourth order tectonic units include uplifts and depressions. This subdivision provides basic geophysical data for geological and tectonic background research and oil gas exploration. In this paper, the authors discussed the magnetic evidence for delineating boundaries of the first and second order tectonic units, and compared them with previous subdivision of tectonic units in China. The third and fourth order tectonic units were completely defined by the feature of magnetic field and fluctuation of magnetic basement. The magnetic basement depth of basins and depression areas are provided in this study, which provides the necessary technical support for oil and gas prospectors. Meanwhile, aeromagnetic anomalies show some special characteristics that are not consistent with observed geological and tectonic features, which provide raw data for discussion of tectonic features of China.