马尼拉俯冲带北段前渊构造层特征及构造含义

Characteristics and tectonic implications of structural layers in foredeep of the northern segment of Manila subduction zone

通过分析南海东北部横切马尼拉俯冲带北段的高分辨率多道地震剖面和区域钻井资料,对该俯冲带北段前渊的构造层特征进行了研究。结果表明,马尼拉俯冲带北段前渊发育以显著的T2和T6不整合分隔的3套构造层,分别对应同裂陷沉积、裂后拗陷沉积和前陆盆地沉积。此外,前渊发育了大量正断层,可分为古近纪同生断层和上新世挠曲正断层。马尼拉俯冲带北段前渊的构造层特征反映了南海东北部从被动陆缘向主动陆缘的构造演化。

By analyzing the high resolution multichannel seismic profiles and regional drilling data in the northeastern South China Sea,the characteristics of the structural layers in the collisional foredeep of the northern segment of the Manila subduction zone are studied.The results show that three structural layers separated by the well-marked T2 and T6 unconformities develop in the foredeep.The structural layers correspond to syn-rift succession,post-rift succession and foreland basin succession respectively.In addition,a large number of normal faults form in the collisional foredeep,which can be divided into Paleogene contemporaneous fauld and Pliocene flexural normal faults.The characteristics of the collisional foredeep in the northern segment of the Manila subduction zone reflect the tectonic evolution of the northeastern South China Sea from passive continental margin to active continental margin.