莺歌海盆地拉张性质的研究

A STUDY OF THE STRETCHING BEHAVIOR OF THE YINGGEHAI BASIN

莺歌海盆地是南海北部陆架盆地的重要组成部分．本文根据ＭｃＫｅｎｚｉｅ（１９７８）的均匀拉张模型，并采用Ｍｉｄｄｉｅｔｏｎ（１９８４）在地震地史分析中的做法，由地震剖面资料得到进行去压实校正所需的地层资料．经过去压实校正和回剥处理，得出了盆地典型剖面的地层埋藏史和热沉降史．然后，由热沉降史通过与ＭｃＫｅｎｚｉｅ的理论曲线的对比，求出拉张因子分布．结果表明，莺歌海盆地为符合ＭｃＫｅｎｚｉｅ模型的盆地，南海的两次扩张在莺歌海盆地形成过程中有明显的反映．

The Yinggehai Basin is an important integral part of the northern shelf basins of the South China Sea Based on McKenzie's(1978) uniformly stretching model andusing the approach similar to that adopted by Middleton (1984)in the seismicgeohistory analysis,we take the observed seismic reflection data as the stratigraphydata employed in the correction of decompaction.Through decompaction and backstripping technique,the stratigraphic burial history and the thermal subsidencehistory for some profiles of the basin are obtained.The distribution of the stretching factor is then determine in terms of a comparison of the thermal subsidence history with the McKenzie's theoretical curves.The results show that the two identified spreading a basin coinciding with the McKenzie's model and that the two identified spreadingevents in the south China Sea played a significant role in the formation of the basin.