南极布兰斯菲尔德海峡的硅质沉积物特征  

FEATURES OF SILICEOUS SEDIMENTS INBRANSFIELD STRAIT,ANTARCTICA

作　　者：吴能友[1,2] 段威武[2] 李华梅[1] 姚伯初[2] 钟和贤[2] 

机构地区：[1]中国科学院广州地球化学研究所 [2]地质矿产部广州海洋地质调查局研究所

出　　处：《极地研究》1998年第2期115-123,共9页Chinese Journal of Polar Research

摘　　要：根据粒度、微体生物组合、矿物组分和微量元素丰度，探讨了南极布兰斯菲尔德海峡中央海槽和南部下陆坡区冰－海沉积环境形成的硅质沉积物特征。硅质沉积物主要为硅藻软泥或粉砂质硅藻软泥，由微体生物遗体、粘土矿物、火山物质和陆源碎屑矿物所组成。硅质生物壳体主要为硅藻，含量＞３０％，含少量放射虫和硅质壳有孔虫。粘土矿物中蒙脱石的含量高达５２．５％，其次为陆源伊利石，高岭石和绿泥石含量相对较低。碎屑重矿物以橄榄石、辉石、角闪石等非稳定组合为特征，轻矿物主要包括石英、长石和火山玻璃。微量元素丰度特征与大洋现代表层沉积物有所区别。研究区硅质沉积作用具有多种物源、生物沉积作用居重要地位、陆源（包括火山）物质以粉砂和粘土级细质点为主、相对较高的沉积速率和受地质构造背景影响等特征。ccording to the grain sizes,microbiological assemblage,mineral composition and minor elements,the features of siliceous sediments deposited in the glacialmarine environment in the central trough and south lower slope of Bransfield Strait,Antarctica were discussed in the paper.Siliceous sediments,mainly diatom ooze or silty diatom ooze,are dominated by the fine grained clastics with particle diameter less than 0.063 mm.Material components include the microbiological remains,clay minerals,volcanic products and terrigenous clastics.The microbiological assemblage show almost all the siliceous organism,chiefly diatom tests and uncommonly radiolaria and siliceous foraminifera.Among the nonbiogenous components,an important proportion is clay minerals with smectite formed by halmyrolysis of volcanic ash and terrigenous illite as the major species.Kaolinite and chlorite are relatively less in quantity.The terrigenous components include heavy minerals,primarily unsteady association such as olivine,pyroxene and hornblende,light ones dominated by quartze and felspar and debrics mainly basic volcanics.Geochemically,the siliceous sediments is different from the superficial sediments deposited in open ocean in minor elements.The siliceous sedimentation of present area under the glacialmarine environment is mainly controlled by the diversified material supplies,certain leading role of biosedimentation,fine grained terrigenous clastics (including the volcanics) with silty and clay sizes,and relatively high sedimentation rate,and directly influenced by the geological and tectonic background.

关 键 词：硅质沉积物 沉积作用 布兰斯菲尔德 海峡 南极 

分 类 号：P736.213[天文地球—海洋地质] P728.2[天文地球—海洋科学]