陈梅, 施小斌, 刘凯, 任自强, 于传海. 南海北缘珠三坳陷新生代构造沉降特征[J]. 海洋地质与第四纪地质, 2017, 37(6): 47-56. DOI: 10.16562/j.cnki.0256-1492.2017.06.005
引用本文: 陈梅, 施小斌, 刘凯, 任自强, 于传海. 南海北缘珠三坳陷新生代构造沉降特征[J]. 海洋地质与第四纪地质, 2017, 37(6): 47-56. DOI: 10.16562/j.cnki.0256-1492.2017.06.005
CHEN Mei, SHI Xiaobin, LIU Kai, REN Ziqiang, YU Chuanhai. CENOZOIC TECTONIC SUBSIDENCE OF THE ZHU Ⅲ DEPRESSION IN THE PEARL RIVER MOUTH BASIN, NORTHERN SOUTH CHINA SEA[J]. Marine Geology & Quaternary Geology, 2017, 37(6): 47-56. DOI: 10.16562/j.cnki.0256-1492.2017.06.005
Citation: CHEN Mei, SHI Xiaobin, LIU Kai, REN Ziqiang, YU Chuanhai. CENOZOIC TECTONIC SUBSIDENCE OF THE ZHU Ⅲ DEPRESSION IN THE PEARL RIVER MOUTH BASIN, NORTHERN SOUTH CHINA SEA[J]. Marine Geology & Quaternary Geology, 2017, 37(6): 47-56. DOI: 10.16562/j.cnki.0256-1492.2017.06.005

南海北缘珠三坳陷新生代构造沉降特征

CENOZOIC TECTONIC SUBSIDENCE OF THE ZHU Ⅲ DEPRESSION IN THE PEARL RIVER MOUTH BASIN, NORTHERN SOUTH CHINA SEA

  • 摘要: 盆地的构造沉降史是盆地基底垂向升降的历史记录,不仅可以反映盆地形成演化历史,而且可能记录了深部地质过程的信息。近年来,越来越多的地球物理证据显示,雷琼地区深部存在延伸到下地幔的柱状低速异常体。为了揭示该深部异常体的活动信息,利用地震资料和钻孔资料,采用回剥和应变速率反演技术,计算了珠三坳陷各构造单元的构造沉降曲线和理论构造沉降曲线。结果显示,珠三坳陷新生代构造沉降可划分为5个阶段:初始张裂慢速沉降(65~49.5 Ma),张裂期快速沉降(49.5~30 Ma),裂后慢速热沉降阶段Ⅰ(30~23.03 Ma),裂后加速沉降(23.03~16.5 Ma),裂后慢速热沉降阶段Ⅱ(16.5~0 Ma)。珠三坳陷在裂陷期存在沉降亏损现象,裂后期存在300~800 m异常沉降可能是对前期沉降不足的补偿,可能与裂陷期软流圈热物质上涌和消退有关。研究结果还表明23.03~10.5 Ma珠三坳陷构造沉降中心发生北东向的迁移,是否与深部异常体活动有关或受区域应力场影响,还需进一步研究。

     

    Abstract: The history of tectonic subsidence is the record of basement movement in vertical direction. It is not only the reflection of basin evolution, but also the record of deep geological process. More and more geophysical evidence accumulated in recent years suggest that there is a low velocity anomaly under the Leiqiong area and its adjacent. In order to reveal the movement information of this deep low velocity anomaly body, we calculated the real tectonic subsidence curves as well as the theoretical tectonic subsidence curves for each tectonic units of the Zhu Ⅲ depression by backstripping and strain rate inversion, based on seismic and drilling data. Results show that the Cenozoic tectonic subsidence of the Zhu Ⅲ depression can be divided into five stages: slow syn-rift tectonic subsidence (65~49.5 Ma), rapid syn-rift tectonic subsidence (49.5~30 Ma), slow post-rift thermal subsidence Ⅰ(30~23.03 Ma), accelerated post-rift subsidence (23.03~16.5 Ma), slow post-rift thermal subsidence Ⅱ(16.5~0 Ma). We find that the Zhu Ⅲ depression exists 300~800 m syn-rift subsidence deficit, and the rapid post-rift subsidence might be the compensation to the deficit probably caused by the dynamic support of the influx of warmer asthenosphere material. The results also show that the tectonic subsidence center of the Zhu Ⅲ depression migrated to the northeast during 23.03~10.5 Ma, together with the deep low velocity anomaly body.

     

/

返回文章
返回