【摘要】 对取自南海东部的 5个沉积岩芯进行矿物学和地球化学研究。结果表明火山碎屑沉积层可分为 2种类型 :1种具高SiO2 ,低FeO ,TiO2 ,MgO和无色玻璃 普通角闪石组合特征 ,火山玻璃富含微量元素Cu ,Sc ,Zr ,为酸性火山沉积成因 ;另 1种以火山玻璃相对低含SiO2 ,高MgO ,FeO ,TiO2 为特征 ,并与褐色玻璃 普通辉石 磁铁矿组合和高V ,Ni的沉积层伴生 ,属中性火山碎屑沉积。晚更新世以来以深海盆为中心曾发生 2～ 5次火山沉积 ,其性质、强度、频率和分布随区域性的变化而不同 ,在晚更新世中期 ( 2 4.1～ 73 .9ka)达到鼎盛。南部海盆属中性火山沉积 ,北部海盆为中酸性 酸性火山沉积。北部陆坡区和南沙礁台区基本上未受到影响。火山碎屑沉积物主要来自海底喷发 ,部分源自菲律宾岛弧。更多还原

【Abstract】 The mineralogy and geochemistry of five sedimentary cores collected from the eastern South China Sea were studied. The results reveal that the volcaniclastic layers can be divided into two types. One type is characterized by high SiO 2, low FeO,TiO 2,MgO,and colourless volcanic glass-hornblende assemblage in the sedimentary layer, with high Cu,Sc and Zr in volcanic glass. The other type, with relatively low SiO 2,high MgO,FeO and TiO 2 and associated with brown volcanic glass-augite-magnetite assemblage and high V and Ni in the sedimentary layer, belongs to a middle volcaniclastic layer. The nature,strength,frenquency and distribution of volcanic sedimentary events varied with region during the late Pleistocene epoch, and two to five volcanic units occurred mainly in the deep basin. It was an active period in the middle of the late Pleistocene epoch (24.1～73.9ka) . The southern basin belongs to middle volcanic sediment, but the northern basin is of middle, acidic to acidic volcanic sediment.However the northern slope areas and Nansha reef-bed areas are not basically effected. The volcaniclastic sediments mainly originated from volcanic eruption under the ocean floor, and they were thought to have been derived partly from the Philippine island arc.更多还原