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对增生楔不同压力—温度条件下的构造变形、流体活动、沉积特征、岩石物性和化学组成等多方面的直接观测,可以帮助分析俯冲带地震的蕴育和发生的环境与机理。通过参加IODP的日本南海海槽发震带研究项目(NanTroSEIZE)第一阶段316航次所收集到的大量第一手数据和资料,分别在4个站位上(C0004,C0006,C0007,C0008)对日本南海海槽增生楔前缘岩芯尺度上的构造变形进行了详细分析,并且讨论了岩芯尺度上的构造变形与增生楔中大尺度的非序列分支逆冲断层和前缘逆冲断层的构造变形之间的关系。发现逆冲变形不是只在大尺度的逆冲断层面上进行,而是弥散分布在主逆冲断层面、次级逆冲断层面以及断层面之间的更小的尺度上。小尺度构造的倾向与大尺度断层的倾向有较好的一致性,表明它们是在相同的应力场下所形成的。在增生楔浅部高角度的正断层比较发育,显示张性应力场特征,同时所获得的岩芯尺度上的地层倾角较大并倾向与反射地震以及区域地质分析结果非常吻合,而在深部,特别是在大尺度逆冲断层发育带附近,各种类型的断层、滑移变形带、节理等非常普遍,同时层理与劈理的产状的复杂变化更多地受控于复杂的逆冲断层带的作用。
The direct observation of tectonic deformation, fluid activity, sedimentary characteristics, petrophysical properties and chemical composition of the accretionary wedge under different pressure-temperature conditions can help to analyze the implication and occurrence environment and mechanism of the subduction zone. Through the large amount of first-hand data and data collected by the IODP’s NanTaiSEIZE Phase 1, 316 voyages at 4 stations (C0004, C0006, C0007, C0008) The tectonic deformation on the core scale of the South China Sea trough accretionary wedge has been analyzed in detail. The tectonic deformation on the scale of the core and the large-scale non-sequence branch thrust faults and frontal thrust faults in the accretionary wedge Relationship between structure and deformation. It is found that the thrust deformation is not only carried out on a large-scale thrust fault plane, but rather on a smaller scale between the main thrust fault plane, the secondary thrust fault plane and the fault plane. The tendency of small-scale structures is in good agreement with that of large-scale faults, indicating that they are formed under the same stress field. The normal faults in the shallow part of the accretionary wedge developed at a relatively high angle and showed the characteristics of the tensional stress field. Meanwhile, the dip of the strata on the core scale obtained by this method was larger and tended to coincide with the reflection seismic and regional geological analysis results. Especially in the vicinity of the large-scale thrust zone, various types of faults, slip deformation zones and joints are very common. The complex changes of bedding and cleavage are more controlled by complex thrusts The role of fault zone.