作　　者： ; ;

机构地区： 中国科学院海洋研究所

出　　处： 《沉积学报》 1997年第A12期8-15,共8页

摘　　要： 本文对冲绳海槽北部(126°30′—129°30′E;28°30′—32°00′N)现代海底表层沉积物的沉积物地球化学特征进行了系统的分析,探讨了分别代表陆源、火山源和生物源沉积物的地球化学指标。结果表明,SiO_2主要富集于东海外陆架与陆架坡折带,基本上反映了陆源碎屑沉积或东海陆架外缘的残留砂沉积;Al_2O_3和Na_2O的含量分布明显与玻屑砂或火山玻璃的含量有关;CaO或CaCO_3代表了生物沉积组份的多寡;MgO、TFe_2O_3、TiO_2、K_2O、MnO、P_2O_5、L.O.I对应于调查区的细粒沉积物。Rb、Ba、Zn和Cr等微量金属元素主要富集于粉砂粘土级细粒沉积物中,但Sr主要富集在生物组份中。绝大多数化学组份的分布呈现出以海槽中轴线为界分为东、西两个区的格局,说明无论从沉积物源上,还是从沉积环境上讲,调查区东、西两侧都有着极为重要的差异。在沉积学上海槽中轴线是一明显的分界线。 Systematic analyses on the seafloor surface sediments of the north Okinawa Trough were carried out to seek for geochemical indexes respectively representing terrigenous,volcanic and biogenic sediments.Research results showed that SiO_2 was riched in the zone of the outer shelf edge and shelf break where the terrigenous sediments and relict sediments were dominant.Al_2O_3 and Na_2O contents were the indexes representing volcanic materials,and CaO or total carbonate indicating the biogenic deposits.In addition, MgO,Fe_2O_3,TiO_2,K_2O,MnO,P_2O_5,LOI(loss by ignition) and most trace metals,such as Rb,Ba,Zn and Cr were comparatively enriched in the fine sediments.Stronsium concentration had close relationship with proportion of the biogenic components in the sediments. Distributions o! most chemical components presented a pattern which was devided into the east area and west area by the middle axis line of the Okinawa Trough,suggesting important differences existing between the two areas in the both sediment resource and sedimentary environment.The middle axis line of the trough was a natural boundary in sedimentology.

关 键 词： 沉积物 地球化学特征 沉积学界线 冲绳海槽

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