南海中南—司令断裂带的延伸特征及其与南海扩张演化的关系

发布时间：2018-06-19 17:42

  本文选题：南海扩张 + 滑线场　； 参考：《海洋地质与第四纪地质》2017年02期

【摘要】：为了确定中南—司令断裂带在南海海盆及其在南部陆缘的延伸位置,并探讨其与南海扩张的关系,本文利用重磁异常、地震、莫霍面深度、P波速度特征、钻井拖网资料,对中南—司令断裂带的延伸位置进行了综合地质和地球物理研究,厘定了中南—司令断裂带在东部次海盆与西南、西北次海盆之间呈NS向延伸,并南延至南海南部陆缘之上,深度上切割至莫霍面。根据南海海盆中磁异常条带走向的变化,及磁异常条带、走滑/转换断裂、扩张方向的印证关系,结合前人对古南海"剪刀状"碰撞闭合、南海扩张演化、构造应力场的研究,提出在32~25 Ma,伴随着南海东部次海盆的NNW向扩张,南海海盆及南沙地块整体发生顺时针旋转,使中南—司令断裂走向由形成初期的NNW向转变为N—S向;23.5 Ma之后,顺时针旋转停止,南海东部次海盆继续NNW向扩张,西南次海盆呈NW—SE向渐进式扩张。作为一条切穿地壳的深大断裂,中南—司令断裂与红河-越东断裂、马尼拉海沟断裂三条深大断裂一起组成区域"滑线场",制约南海海盆的扩张与南沙地块的南移。
[Abstract]:In order to determine the extension position of the SCS fault zone in the South China Sea basin and its southern margin, and to discuss its relationship with the South China Sea extension, this paper makes use of gravity and magnetic anomalies, earthquakes, Moho depth P wave velocity characteristics, drilling trawl data, etc. A comprehensive geological and geophysical study on the extension position of the Zhongnan-Shing fault zone has been carried out. It has been determined that the SCFZ extends in a NS direction between the eastern suboceanic basin, the southwest subbasin and the northwest subbasin, and extends south to the southern margin of the South China Sea. Cut deep to Moho. According to the change of the trend of the magnetic anomaly belt in the South China Sea basin, and the relationship between the magnetic anomaly belt, the strike-slip / transition fault, and the direction of the expansion, combined with the previous studies on the closure of the "scissors" collision in the ancient South China Sea, the expansion and evolution of the South China Sea, and the tectonic stress field. It is suggested that at 32 ~ 25 Ma, with the NNW expansion of the subbasin in the eastern part of the South China Sea, the whole South China Sea basin and Nansha block rotated clockwise, which changed the strike from NNW to N-S to 23.5 Ma in the early stage of the formation of the South China Sea and Nansha Block. The subbasin in the eastern part of the South China Sea continued to expand in the NNW direction, and the subbasin in the southwest of the South China Sea was gradually expanding in the direction of NW-SE. As a deep fault that cuts through the earth's crust, the three deep faults, namely, the south-central fault and the Honghe-Yuedong fault, and the Manila trench fault, together form the regional "slip field", which restricts the expansion of the South China Sea basin and the southward migration of the Nansha block.
【作者单位】： 中国科学院南海海洋研究所边缘海与大洋地质重点实验室;中国科学院大学;广州海洋地质调查局国土资源部海底矿产资源重点实验室;
【基金】：国家自然科学基金项目(41276048,91328205,41606080和41476039) 中国海及邻域地质地球物理及地球化学系列图项目(GZH200900504-WX02)
【分类号】：P736
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本文编号：2040730