南海东北部陆缘区新近纪早期反转构造特征及其动力学意义

Inversion structure features and their dynamic significances in Early Neogene strata at continental margin of the northeast South China Sea

通过深入分析"九七三"项目所获取的高分辨率多道地震剖面,结合区域钻井资料,探讨了新生代以来南海东北部陆缘所历经的新生代早期张裂、中新世晚期阶段性挤压及上新世以来的稳定热沉降等复杂构造运动;张裂背景下的南海东北部陆缘在中新统中部、下部出现的背斜、逆断层等典型压性反转构造,凸现了南海东北部陆缘在晚中新世发生的阶段性挤压构造运动;分析表明,此构造活动是东沙运动在台西南海域的表现,其动力来源同菲律宾海板块的北西向运动有关。

Combing with regional well-log data, the complicated tectonic movements were explored at conti- nental margin of the northeast South China Sea （SCS） such as rifting at Early Cenozoic, phasic extrusion at Late Miocene and stable thermal sedimentation after Pliocene by analyzing high resolution multi-channel seismic profiles acquired in the national ＂973＂ project. Therein, the typical extruding inversion structures such as anticlines and reversed faults existing at Mid--Lower Miocene strata especially in back of totally rifting evolutionary conditions manifested the phasic extruding tectonic movement occurred at about Late Miocene in the northeast SCS. Analyzed results show that the inversion structure is the external perform- ance of Dongsha movement. And its dynamic origin is related to the northwest movement of Philippine Sea Plate.