陕甘宁盆地遥感地质特征
Remote sensing geological characteristics of the Ordos Basin
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摘要: 通过对1∶25万TM卫星1、4、7波段假彩色合成影像图及其东西、南北、北东及北西方向上的线性增强图,1∶3.5万和1∶5万的航空照片的解译,结合野外实地考察,得到如下结果:a.陕甘宁盆地线性断裂构造发育,可划分出东西、南北、北西、北北西、北东、北北东等6组断裂。它们在空间上呈现出近等间距性、网络格局、断续成带的特点;在活动性上具有断距小、隐伏性、强度低的特点。它们明显地控制着现代地形、地貌及水系的发育,表明陕甘宁盆地内部新构造活动较为明显。b.盆地南北遥感影像有着明显的差异,反映两者地质构造的差异性,特别是盆地南部地区存在一个基本围限了盆地南部黄土高原地区的巨大的环形影像,其边缘影像十分清晰,中间区域穿插了略呈格状的北西-北北西,北东-北北东、东西及南北向的断裂。该环形影像是盆地中南部控边构造的多期活动、复合、叠加、联合而成的综合影像,并不反映盆地南部存在整体大规模的顺时针或逆时针的环型块体转动。Abstract: Based on field work and the interpretation of the 1:250,000 satellite TM image of the Ordos Basin, the authors found:a. There are many linear faulted structures with six different strike directions in the Ordos Basin, which are buried, small in fault throw and little in strength. The faults in the same direction extend as discontinuous belts and the distance between two adjacent belts are approximately constant, and all the belts with different directions show a gridding pattern. These faults are obviously controlling the topography, physiognomy and water systems. This provides a convincing evidence of neotectonic movements in the basin. b. There are many differences between the remote sensing images of the south basin and the north basin, which indicate that the geologic structures in the two areas are very different. It is notable that there is a huge annular image with a clear edge in the south Ordos Basin. It almost covers all the area of the Loess Plateau in the basin and in which there are four series of faults with different strike direction, NW or NNW, NE or NNE, EW and SN. This annular image is a result of complicated movements of the structures in the middle and south basin which control the boundary of the basin, does not indicate that there is a huge annular plate rotating in the south of the basin.