南极中国长城站地区西湖沉积物的地球化学行为与环境

本文对取自长城站区西湖水下沉积物260cm岩芯采用中子活化等方法分析得出:湖区周边的新生代火山岩构成了西湖沉积物的主要物源.粘土粒级中元素有明显的化学分异作用.沉积物中Cs/Rb,Br/Cl,La/Yb,CaCO_3及粘粒中阳离子代换量的变化表明3.6ka B.P.以来,气候存在温和—寒冷—温和的变化,反映该区冰盖进退的历史.     

CHANGES OF SEDIMENTARY ENVIRONMENT SINCE THE LATE PLEISTOCENE IN VESTFOLD HILLS AREA, ANTARCTICA

The Vestfold Hills area was a shallow-sea sedimentary environment in the interglacial stage (50,000—25,000 yr B.P.) of the last glacial period of the Late Pleistocene, and later became a glaciofluvial environment. This marine sedimentary plain was covered by glaciers at the time of 31,000—11,000 yr B.P. After the last glacial period (6500—3500 yr B.P.), the retreat of ice sheets in this area resulted in the formation of lakes and lagoons, followed by alternating sedimentation of three-times sub-turbidity current and two-times ice-melt water. Sulphate-Glauber salt was deposited in the inland depressions. The advance of the ice sheets in this area during the neo-ice age (2800 yr B.P.) resulted in three parallel moraine terraces consisting of boulders and coarse sands composed mainly of hornblende, and subordinately of garnet and magnetite. During this period a Si-AL-chloride detrital weathering crust was developed on hyperthenite with schistose actinolite. In addition to physical weathering (e.g. frost     

南极Davis站地区晚更新世以来沉积环境的演变

本文论述了该区在晚更新世末次冰期中的间冰段时期(距今50000—25000年)为浅海沉环境,后转变为冰融水环境,在31000—11000年时,本海积平原被冰川覆盖,末次冰期以后(距今6600—3500年),该区冰盖退缩形成湖泊与泻湖,出现三次“似浊流”与两次冰融水相交替沉积,在2800年新冰期时,本区冰盖前进,形成以普通角闪石为主,次为石榴石与磁铁矿的巨砾夹粗砂的三道冰碛垄,在此时段片理化阳起石、苏长岩的基岩上发育了硅铝-氯化物碎屑型风化壳。除寒冻物理风化作用外,化学风化作用也十分明显。     

A PRELIMINARY RESEARCH ON WEATHERING PROCESS IN CASEY STATION, EAST ANTARCTIC

The chief aim of this preliminary work is to investigate the weathering process of the bed rock and moraine in Antarctic by the method of sedimentology. Microfractures, the depth of which is less than 1 cm, and macrofissures are formed through frost weathering process. The chemical composition of the weathering products are observably related to their size due to migration process. Weathering materials are relatively rich in rare-earth elements of Ce family. Weathering clay minerals are mainly illite hydromica which can considerably absorb the elements of Ti, K, Cs, Rb, Sc, Sb, As and Fe. The weathering crust of the bed rock has hardly any CaCO_3 component, it belongs to primigenial debris weathering crust, with only a slight As pollution.     

GEOCHEMISTRY OF SEDIMENTS AND ENVIRONMENT IN XIHU LAKE OF GREAT WALL STATION OF CHINA, ANTARCTICA

The determined results in this paper, which were obtained by the multielement analysis of the 260 cm-deep core sediments under the water of Xihu Lake in the Great Wall Station area, are as follows: The Cenozoic volcanic rocks around Xihu Lake are the main source of sediments in the lake. The chemical differentiation in very fine particles is still detectable. From the variation of ratios of the Cs/Rb, Br/CI and La/Yb in the clay fraction with depth and from the variation or CaCO_3 contained in the sediments, cation replacing amount in the clay grains and the sediment grain sizes in time, it can be seen that since 3600 a. B. P., there has existed the climatic variation of warm-cold-warm, which embodies the advance and retreat history of the ice sheet in this area.     

东南极凯西站地区风化过程的初步研究

本文主要用沉积学方法研究南极地区基岩和冰碛砾石的风化作用。寒冻物理风化作用形成宏观裂缝及微裂纹,后者所达深度在1cm以内。不同粒级风化物的化学元素有明显的分异现象。风化物为富铈族稀土的选择配分型。风化粘土矿物以伊利水云母为主,对Ti,K,Cs,Rb,Sc,Sb,As,Fe有较强的吸附作用。基岩风化壳中完全不合碳酸钙,属最原始的碎屑型风化壳、有轻微的砷元素污染现象。