The Research Of Structural Characteristics In Eastern Nanpanjiang Depression And Its Adjacent Area

Based on first-hand materials, five regional faults (Nandan-Du'an fault zone, Nanpanjiang fault zone, Youjiang fault zone, Bama fault zone and Xialei-lingma fault zone) were analyzed systematically which controlled the structural framework of the whole area. Through discussing their activity and controlling basin behavior in different stage, fault zones' expression forms, and the activity mechanism of different section in different stage.Based on the four geologic structural section (2 pieces NE-SW direction, 2 pieces nearly EW direction) which controlled different structural area and several supplementary profiles and several other auxiliary sections, summarize and analyze the structural style research area. Surface structural styles shown on great profiles were discussed in different structural section after continual observation. Structural characteristics of inversion structure, fold association style, thrust fault zone upright strata developed belt shown in great profiles were also discussed.Combined with geologic condition and infrastructure characteristics, balance three great structure profiles which trend SN with balance profile theory, then analyze the structure style , association form and each detachment further ,and calculate 30% shorten after the stratum deformation variant It turns out to be striking detachment in multiple tectonic levels and different structure deformation variant style in different stage, after the discussion of the structure style and relation between infrastructure and suprastructure.In summary, we constructed a structure framework on the eastern district of the Nanpanjiang depression, made a new structure regionalism, confirmed that the border of Nanpanjiang depression was Nandan-Du'an fault and Xialei-Lingma fault, and analyzed the structural characteristics of secondary structure units in detail.According to the analysis of the structure deformation variant direction the structure superposition during late period, and the tectonic stress field and deformation variant field, the cover extended nearly SN direction in early stage(D-C), maybe changed the direction in Pernian(especial the late Permian), and developed some new half-graben along SN direction except the succession activity at great fault zone .The direction of compression deformation variant, however, was nearly SN direction in Indo-Chinese epoch, NE-SW direction in early Yanshan movement epoch, NNE-SSW direction in late Yanshan movement epoch, and transformed from EW to SN direction in Himalayan movement epoch.It is concern of the main tectogenesis and its form since Caledonian, and dynamics mechanism in this paper. From the analysis above ,it is proposed that this area is related to the happen, development of Tethys in the south, and the structure history of the area nearly Pacific Ocean. Based on all above, the basin tectonic evolution is analyzed.