【摘要】 欧亚大陆东南缘早新生代古地理演变包含了华南沿海中生代山脉的逐步消减与南海的逐步扩张形成等重大事件。南海北部始新统—下中新统"源-汇"路径研究发现,南海沉积物物源在该时期发生了巨大改变。在始新世和早渐新世,源自南海西部古隆起的"昆—莺—琼"河流系统向南海东部地区输送了大量沉积物,包括珠二坳陷在内的南海北部南侧大部分地区受南海西部物源的控制,仅在珠一坳陷接受来自华南大陆珠江的沉积物;晚渐新世,南海西部物源逐步被北部珠江物源取代;到早中新世,珠江来源沉积物全面越过番禺低凸起进入珠二坳陷,大量来自华南内陆的沉积物被珠江运输至南海盆地,"昆—莺—琼"古河流进一步萎缩,仅在南海西部琼东南盆地分布,并且由西向东沉积物源区昆嵩地块逐渐被海南岛取代。南海西部自晚中新世以来发育的中央峡谷正是该古河流的残余。南海新生代早期"昆—莺—琼"河流系统的发现及珠江演变过程的构建,对于深刻认识该地区新生代早期古地理特征、整个欧亚大陆东南缘的古地貌重建以及盆地的油气勘探均具有重要意义。更多还原

【Abstract】 During the Early Cenozoic,the southeastern margin of Eurasian Plate has experienced multiple episodes of large-scale palaeographical changes. Overall,with the rapid spreading of the South China Sea( SCS),the Mesozoic orogenic belts in southeast China Continental Block continuingly suffered from erosional processes. Drastic variations of provenance distribution patterns took place in the northern SCS in light of our Eocene-Lower Miocene "source-to-sink" analysis. During the Eocene-Early Oligocene,"Kontum-Ying-Qiong" River has delivered large abundance of materials from the western palaeouplifts into the eastern SCS basins. Briefly,most southern areas including Zhu-II Depression were dominated by this western sedimentary source,while Zhu-I Depression was mainly influenced from the palaeoPearl River to the north. During the Late Oligocene,Pearl River system turned to develop into a larger scale,which gradually exceeded the impact of the western provenance. The sedimentary distribution pattern was completely changed when it came to the Early Miocene. With much less hindrance from PanyuLow-Uplift in the middle,the Pearl River was then transporting voluminous sediments from the South China hinterland into Zhu-II Depression. By contrast,"Kontum-Ying-Qiong" River simply cast fairly limited influences on Qiongdongnan Basin. From west to east,the provenance was gradully replaced from Kunsong Block to Hainan Island. Actually,the Central Canyon which was subsequently formed in the Late Miocene,which was considered as a residual structure of the palaeo "Kontum-Ying-Qiong" River. As a conclusion,the discovery of palaeo "Kontum-Ying-Qiong" River as well as the Pearl River evolution reconstruction proves to be of great significance on( 1) both palaeogeography of the SCS and palaeogeomorphology of the southeastern Eurasian margin in the Early Cenozoic;( 2) the petroleum industrial exploration on the SCS basins.更多还原