琼东南盆地古近系沉降特征
SUBSIDENCE CHARACTER OF THE PALEOGENE QIONGDONGNAN BASIN
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摘要: 在建立层序地层格架的基础上,对琼东南盆地古近系各个层位沉降史进行了回剥分析。研究表明,琼东南盆地古近系沉降中心不断迁移,沉积中心不断扩大,沉降速率随构造活动程度的变化而发生变化。琼东南盆地的12个凹陷可分为2个沉降梯队,西北及东南部总体上为非沉降区。通过选取各个凹陷中的典型点(最深位置)做出单点上的回剥模拟结果可知,琼东南盆地断陷期的3幕表现明显,构造沉降所占的比例逐渐减少,整体上琼东南盆地中央凹陷带东南区的沉降大于西北区。Abstract: Back-stripping analysis for Paleogene subsidence history in the Qiongdongnan Basin is made based on the sequence stratigraphic framework. The result shows that the center of subsidence was shifting for different depositional stage, and the rate of settlement changing with the intensity of tectonic activities. Two echelon of settlement are identified in the Qiongdongnan Basin, but the north-west and south-east parts are non-settlement areas. From the result of back-stripping simulation in the deepest position, there are three major faulting episodes in the basin, and the rate of subsidence is decreasing one after another. The subsidence in the south-east part of the central depression zone is faster than that in the north-west part.