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南海北缘及华南沿海在新生代经历了复杂的盆-岭构造演化历史。目前对南海北部大陆边缘的研究大多集中于南海北缘盆地构造演化,而对南海北缘新生代盆-岭构造格局及大陆边缘地貌演化还缺乏完整的认识。盆地沉积物源区示踪和邻区岩体剥露过程的综合对比研究是深入探讨大陆边缘构造和地貌演化的重要途径。文章详细介绍了目前关于盆地沉积物源区示踪和山脉隆升剥蚀过程的主要方法和进展。综合分析南海北缘盆地碎屑沉积物来源及华南沿海主要岩体剥露过程矿物热年代学的已有研究成果,对南海北缘新生代地貌演化及盆地沉积物剥蚀-沉积过程进行了双重约束。华南沿海主要岩体锆石、磷灰石裂变径迹和磷灰石(U-Th)/He热年代学分析结果表明,南海北部大陆边缘演化过程较为复杂,剥蚀过程表现为明显的多阶段性且剥蚀中心由南向北迁移,与典型被动大陆边缘演化有明显的区别。总体上,~25Ma之前的沉积物εNd值较高、碎屑锆石以年轻颗粒(<500Ma)为主,表明物源以华南沿海地区的中生代花岗岩近源剥蚀为主;而~25Ma之后的沉积物εNd值较低、前寒武纪碎屑锆石年龄(>500Ma)明显增加,表明物源向华南内陆逐渐迁移。南海北缘盆地沉积物来源由近源向远源的逐渐转变,反映了东亚大陆边缘主要水系,如珠江和闽江等由沿海向内陆的侵蚀扩展过程,这一过程对应于南海的扩张和青藏高原东缘的隆升。
The northern margin of the South China Sea and the coast of South China experienced complicated basin-ridge tectonic evolution during the Cenozoic. At present, most of the studies on the continental margin in the northern South China Sea focus on the tectonic evolution of the basin in the northern margin of the South China Sea. However, there is a lack of complete understanding of the Cenozoic basin-ridge tectonics and evolution of the continental margins on the northern margin of the South China Sea. The comprehensive comparative study of the tracing of the sedimentary source of the basin and the detachment process of the adjacent rock mass is an important way to deeply explore the continental margin structure and the evolution of the landform. The paper introduces in detail the main methods and progresses of the tracing of the sedimentary source in the basin and the process of uplifting and erode in the mountains. Based on the analysis of the origin of clastic sediments in the northern margin of the South China Sea and the mineral thermal geochronology of the main rock mass exhumation in the South China Sea, the dual-constraint on the evolution of the Cenozoic landscape and the denudation and sedimentation of sediments in the northern margin of the South China Sea . The zircon-apatite fission track and U-Th / He thermochronological analysis of the main rock mass in the South China Sea show that the evolution of the continental margin in the northern South China Sea is complex and the denudation process is obviously multi-stage And the erosion center migrates from south to north, which is obviously different from the evolution of the typical passive continental margin. In general, εNd values of the sediments up to ~ 25Ma are high, and the detrital zircons are mainly young particles (<500Ma), indicating that the provenance is dominated by near-area erosion of Mesozoic granites along the coast of South China; whereas sediments after ~ 25Ma The value of εNd is low, and the age of precambrian detrital zircons (> 500Ma) is obviously increased, indicating that the source of sediment migrated to the interior of South China. The source of sediments in the northern margin of the South China Sea gradually changed from near to far source, reflecting the erosion from the coastal to the inland of the main rivers in the East Asian continent, such as the Pearl River and the Min River. This process corresponds to the expansion of the South China Sea and Uplift of the eastern edge of the Qinghai-Tibet Plateau.