【作者】 赵长煜；

【导师】 刘光鼎； 宋海斌；

【作者基本信息】 中国地质大学(北京) ， 地球探测与信息技术， 2012， 博士

【摘要】 南海是西太平洋重要的边缘海，面积约为350万km2，处于欧亚板块、太平洋板块和澳大利亚－印度板块的交汇处，自中生代以来经历了东亚边缘大规模的地块拼合、构造挤压、伸展-走滑改造和特提斯的关闭，以及新生代华南大陆岩石圈拉张破裂、海盆扩张、太平洋板块和印度-澳大利亚板块的俯冲、碰撞等构造活动，形成了南海地区丰富的地质现象。因此，南海被认为是研究大陆边缘形成演化以及动力学的天然场所。本文基于朱夏院士提出的TSM盆地模拟思想和刘光鼎院士提出的中国油气的“三海战略”，依托国家基础研究发展规划项目《南海大陆边缘动力学与油气资源潜力》、中石化海相前瞻性研究项目《中国陆域海相沉积盆地热体制与油气资源潜力》和中海石油研究中心国家油气重大专项“十一五”子课题《南海北部深水区热演化及其对烃源岩生烃的控制》，进行了西南次海盆的地震解释，以及南海南、北大陆边缘主要沉积盆地的构造-热演化模拟。NH973-1测线的地震资料解释揭示了西南次海盆洋壳基底的差异，其可能与海底扩张速率和岩浆活动的阶段性过程有关，而南缘陆坡坡脚的巨厚的堆积体可能是新生代沉积的重力滑塌堆积的结果，但不排除残存有中生代地层的可能。南海北部边缘沉积盆地的构造-热演化模拟，揭示了该区域的沉降期次和加热过程存在明显差异，构造运动、断裂活动和岩浆作用的差异造成了南海北部边缘沿走向变化的构造、热演化过程。琼东南盆地第二期加热事件与南海运动和海底扩张相对应，琼东南西部和珠江口盆地的加热过程出现了明显的滞后，并且琼东南盆地晚期上新世的热事件，自西向东的加热事件逐渐变弱，至珠江口盆地消失。南海南部大陆边缘的沉积盆地的构造－热模拟，揭示了南部边缘热状态的区域展布特征，即自SW向NE逐渐变冷，且深水区热流明显高于浅水区。南部边缘受南海扩张后的挤压碰撞－走滑改造作用明显，而北部边缘晚期的构造活动更具有区域的独特性。更多还原

【Abstract】 As an important marginal sea in the Western Pacific, the South China Sea (SCS)is about 3.5 million km2, experienced complex history with the three large plates’interaction among the Eurasian Plate, the Pacific plate and the Australia-India plate.The South China Sea has been considered as one natural laboratory on continentalmargin tectonics and dynamics research, which experienced the large-scaleconvergence, collision, strike-slip and the close of Tethys during the Mesozoic period,and continental margin lithosphere breakup, the central and southwestern subbasinseafloor spreading, the Pacific Plate and the Indo - Australian plate subduction andcollision during the Cenozoic period.In this paper, based on the TSM basin modeling thoughts proposed byacademician Zhu, and“Three Sea Strategy”proposed by academician Liu, supportedby the National Basic Research Development Program of the South China Seacontinental margin dynamics and oil & gas resource potential, SINOPECforward-looking research project, and CNOOC national oil & gas special project, wefinished seismic interpretation and modeling of the southwestern subbasin of SouthChina Sea, tectonic and thermal modeling of main sedimentary basins on the southernand northern continental margin of South China Sea.Line NH973-1 interpretation shows that the different oceanic crust basement ofsouthwestern subbasin of South China Sea suggests the different spreading rate,magmatism and deformation under different seafloor spreading rate. Huge thickenedsedimentary body at the tip of the southern lower slope may be formed in theCenozoic era and affected by later gravity slump.The rifted sedimentary basins on the northern SCS show different subsidence andheating process, which is controlled by tectonic movement, fault and later periodmagmatic activity. The second heating period in the Qiongdongnan Basin correspondsto NanHai movement and the onset of seafloor spreading, but the end time delayed atthe southeastern part of the Qiongdongnan Basin and the Pearl River Mouth Basin.Late Pliocene thermal event at Qiongdongnan Basin resulted from a very strong rapidsubsidence, the heating effect weakened from west to east, and disappeared in thePearl River Mouth Basin.It is different for the thermal history of the southern continental margin of SCS.Southern continental margin shows gradual cooling from SW to NE, and the basementheat flow in the deepwater region is higher than that in the shallow water regionobviously. Later period thermal evolution on the southern continental margin wascontrolled by convergence, collision, and strike-slip activity in the area, but at thesame period the northern continental margin experienced different activity.更多还原