CAJ | 학술논문

40a的海洋地质、地球物理实测研究表明，九段线不仅是显示我国南海主权的历史性水域线，而且总体上也是南海与东部、南部和西部陆区及岛区的巨型地质边界线。根据实测数据，本文将从地质成因、来源、演化的角度论述此南海历史性水域线的合理性。主要结论包括：历史性水域线的东段在地形上基本与马尼拉海沟一致，海沟西侧为南海中央海盆洋壳区，东侧为菲律宾群岛。根据国际地质研究的资料，菲律宾群岛始新世以前位于较偏南的纬度，后来于中晚中新世（距今16～10Ma）仰冲于南海中央海盆之上，因此菲律宾群岛是一个外来群岛。而黄岩岛在马尼拉海沟以西，是中央海盆洋壳区的一个岛礁，与菲律宾群岛成因不同。南海历史性水域线的南段在地形上基本与南沙海槽一致，伴随南沙地块由北部陆缘向南裂离，古南海洋壳沿此海槽以南俯冲至加里曼丹岛陆壳之下，因此南沙地块与加里曼丹陆块为两个来历不同的地块。南海历史性水域线西段的分布在地形上与越东巨型走滑断裂带基本一致，可能与西沙地块、中沙地块、南沙地块从南海北部陆缘向南滑移有关。南沙地块北缘陡直的正断层结构，突显中央海盆是拉裂形成，其基底和中新生代地层与北部珠江口盆地的地层结构可以对比，说明南沙岛礁原属我国华南大陆南缘，后因南海的形成裂离至现今的位置。
40a적해양지질、지구물리실측연구표명，구단선불부시현시아국남해주권적역사성수역선，이차총체상야시남해여동부、남부화서부륙구급도구적거형지질변계선。근거실측수거，본문장종지질성인、래원、연화적각도논술차남해역사성수역선적합이성。주요결론포괄：역사성수역선적동단재지형상기본여마니랍해구일치，해구서측위남해중앙해분양각구，동측위비률빈군도。근거국제지질연구적자료，비률빈군도시신세이전위우교편남적위도，후래우중만중신세（거금16～10Ma）앙충우남해중앙해분지상，인차비률빈군도시일개외래군도。이황암도재마니랍해구이서，시중앙해분양각구적일개도초，여비률빈군도성인불동。남해역사성수역선적남단재지형상기본여남사해조일치，반수남사지괴유북부륙연향남렬리，고남해양각연차해조이남부충지가리만단도륙각지하，인차남사지괴여가리만단륙괴위량개래력불동적지괴。남해역사성수역선서단적분포재지형상여월동거형주활단렬대기본일치，가능여서사지괴、중사지괴、남사지괴종남해북부륙연향남활이유관。남사지괴북연두직적정단층결구，돌현중앙해분시랍렬형성，기기저화중신생대지층여북부주강구분지적지층결구가이대비，설명남사도초원속아국화남대륙남연，후인남해적형성렬리지현금적위치。
Forty years of geological and geophysical investigation and research made us clear that Chinese Historical Sea Lines (abbreviated as CHSL) in the South China Sea (SCS) not only demonstrated our sovereign right ,but al-so a combination of giant geological boundaries between continental blocks ,islands and countries .This paper will focus on the geological rationality of the CHSL in SCS ,based on the investigation of geophysical features ,regional geological structures ,origin and evolution .The main conclusions are :the location of the eastern CHSL is consist-ent with the Manila Trench in topography .The west side of the trench is the Central Sea Basin of the SCS ,with 4 km to 8 km oceanic crust .The east side of the trench is Philippine Archipelago .Based on paleomagnetic analysis , this archipelago was originally a small continental block located in the south latitude .It drifted northward to the present location along the Manila Trench since Middle to Late Eocene (about 16 Ma to 10 Ma) ,and thrusted on the oceanic crust of the Central Basin of South China Sea due to the combined action of Pacific Plate and Australia Plate .Thus ,the Philippine Archipelago was outside source island arc block .The Huangyan Island is located west of the Manila Trench .It's a volcanic island of oceanic crust of central sea basin of South China Sea .It doesn't be-long to the Philippine Archipelago .The location of the southern CHSLs of the SCS in topography is consistent with Nansha Trough .Accompanied with the Nansha Block splitting southward from the northern margin ,the oce-anic crust of proto South China Sea moved southward and subducted beneath the Kalimantan Continent along the Trough .Thus ,Nansha Block was absolutely a different geological source continental block from the Kalimantan Continent .The location of the western CHSLs of South China Sea is the same in topography features as a giant East Vietnam Fault .The Fault might be related to the southward shift of the Xisha ,Zhongsha and Nansha Block from north of the SCS .The north edge of Nansha block showed steep and straight normal faults ,meaning that the Central basin of the South China Sea was mainly evolved by extension .Multi-channel seismic profiles ,drilled re-cords as well as the dredged samples showed that the stratigraphic divisions of several Nansha basins ,Zhongsha and Xisha Block were very similar to and might be fully compared with that of the Pearl River Mouth Basin on the northern continental margin and paleo South China Continental Plate ,so the Xisha ,Zhongsha and Nansha Block o-riginally belonged to the South China Continent ,latterly it was split away and moved southward to present location owing to the evolution of South China Sea .