南海转换断层成因机制及对南海扩张的启示

发布时间：2018-02-06 07:15

本文关键词： 转换断层右行走滑断层板块重建南海海盆　出处：《海洋地质与第四纪地质》2017年04期 　论文类型：期刊论文

【摘要】：转换断层是揭示边缘海盆地演化的一把钥匙,但其成因机制一直都是地质科学研究的难点和热点。基于高分辨率海底构造地貌、盆地发育几何学结构、重磁异常、磁条带分布样式、莫霍面埋深、海底热流和南海北部地震剖面等资料对比,并结合区域地质背景、板块重建、动力学来源,重新厘定了南海海盆转换断层和邻区走滑断层的分布,尤其是其走向,统一归结为NNE向。另外,从转换断层走向的角度入手,提出了边缘海盆地扩张的新模式,并修正了前人对新生代南海的板块重建方案。南海海盆真正的转换断层方向应该是NNE向,并不是传统上认为的NW向。NNE向转换断层及南海的扩张,可能为继承邻区裂解陆缘走滑断层方位的模式。NNE向转换断层实际上就是在南海陆架中广泛分布的NNE向大型右行走滑断层,也是华南地块上一系列NNE向右行走滑断裂在海上的自然延伸,进而提出南海转换断层实际上是继承了邻区陆地上大型走滑断层的走向。这种模式并不是类似于正常洋中脊那样的正向扩张,而是一种斜向扩张,转换断层不垂直于扩张中心。
[Abstract]:Transformation fault is a key to reveal the evolution of marginal sea basin, but its genetic mechanism is always a difficult point and hot spot in geological science. Based on the high-resolution submarine tectonic landform, the basin develops geometric structure. Gravity and magnetic anomalies, distribution patterns of magnetic stripes, depth of Moho surface, submarine heat flow and seismic profile of the northern South China Sea are compared, combined with regional geological background, plate reconstruction and dynamic sources. The distribution of the transition fault and the strike-slip fault in the adjacent area of the South China Sea basin has been redefined, especially its strike, which can be attributed to the NNE direction. In addition, starting from the angle of the transition fault strike. A new model of marginal basin extension is proposed, and the former plate reconstruction scheme for the Cenozoic South China Sea is revised. The true transformation fault direction of the South China Sea basin should be the NNE direction. It is not traditionally thought of as the NW. NNE trending transition fault and the South China Sea extension. In fact, the NNE trending transition fault is a large NNE strike slip fault widely distributed in the South China Sea shelf. It is also a natural extension of a series of NNE right strike-slip faults on the South China block. It is suggested that the South China Sea transform fault actually inherits the strike of the large strike slip fault on the adjacent land. This model is not like the normal mid-ocean ridge, but an oblique extension. The transition fault is not perpendicular to the spreading center.
【作者单位】：江苏省电力设计院;海底科学与探测技术教育部重点实验室;青岛海洋科学与技术国家实验室海洋地质过程与环境功能实验室;中国地质科学院岩溶地质研究所;
【基金】：国家自然科学基金项目(41325009,41190072,41502321,41402172,41502042,41502185) 山东省泰山学者特聘教授项目鳌山卓越科学家计划项目(2015ASTP-0S10)
【分类号】：P736.1

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