Tectonic evolution of the faulted block indicated by the deformation of the planation surface: Example from the research of the Yuguang Basin south marginal fault in the Northwest Beijing basin-ridge tectonic zone
Wang Lin Tian Qinjian
Key Laboratory of Earthquake Prediction, Institute of Earthquake Science, China Earthquake Administration, Beijing 100036
Most existing research of active fault mainly focuses on the single fault itself. Fault is often studied isolatedly, ignoring its neighboring tectonics. If the research scale extends to the whole active faulted block, we can better understand every active fault related consisting of the faulted block. The analysis of the tectonic deformation of the layered landform surface is an effective method to study the tectonic evolution. In recent years, the launching of domestic remote sensing satellite has brought about massive data of high resolution image, the software and technology of GIS has also developed rapidly, which provide an opportunity to study the tectonic movement of the active faulted block in the Northwest Beijing basin-ridge tectonic zone through the deformation of the planation surface in the mountainous area in North China. In this paper, based on the 1 m panchromatic image and 4 m multispectral image of the GF2 satellite, the 1∶ 50 000 digital line graphics, by means of ArcGIS, we interpret two typical planation surfaces in the uplifting block of the Yuguang Basin south marginal fault（YBSMF）, including the Dianziliang and the Tangxian planation surface. We extract the quantity factors which can reflect their tectonic deformation, and analysis the characteristics of their tectonic deformation. Finally, we find that an NE fault（F）cuts through the Yuguang Basin and the Lingqiu Basin at its southwest, and cuts the uplifting block of the YBMSF into two secondary blocks: The east and the west. The strain of the YBMSF patitions at fault F, and a portion of the
original strain has transferred to the Lingqiu basin tectonic system through fault F. The Yuguang Basin and a series of similar graben basins nearby are subjected to the SE-NW regional extensional stress field, which caused the formation of the main NE faults in the region. The tectonic movement of the secondary faulted block at the east and the west are different due to the different lithology. At the west, the block faulted in the Archean metamorphic basement causing the whole tilting of the block. While at the east, the Yanshanian intrusive granite hindered the whole tilting of the block, so the block adjusted the way of movement which caused the tilting decreased gradually inward. The fault F accommodated the different tectonic movement of the faulted blocks at its west side and east side.
Wang Lin Tian Qinjian. Tectonic evolution of the faulted block indicated by the deformation of the planation surface: Example from the research of the Yuguang Basin south marginal fault in the Northwest Beijing basin-ridge tectonic zone[J]. Chinese Journal of Geology, 2017, 52(3): 801-817.