地理学报 ›› 1997, Vol. 52 ›› Issue (1): 80-88.doi: 10.11821/xb199701010

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北极阿拉斯加巴罗湾湖沉积地球化学特征及其环境意义

杨惟理, 王国, 张青松   

  1. 中国科学院国家计划委员会地理研究所,北京100101
  • 收稿日期:1995-08-01 修回日期:1996-05-01 出版日期:1997-01-15 发布日期:1997-01-15
  • 基金资助:
    国家自然科学基金(49571072),中国科学院特别资助项目成果

LAGOON SEDIMENTS GEOCHEMISTRY AND ITS SIGNIFICANCE IN STUDY OF CLIMATIC AND ENVIRONMENTAL CHANGE IN BARROW,ALASKA

Yang Weili, Wang Guo, Zhang Qingsong   

  1. Institute of Geography, Chinese Academy of Sciences and the State Planning Commission of P.R.China, Beijing 100101
  • Received:1995-08-01 Revised:1996-05-01 Online:1997-01-15 Published:1997-01-15

摘要: 本文研究了北极阿拉斯加巴罗Elson湖钻孔沉积岩芯中化学元素的分布及其集散规律;粘粒、有机质环境要素与化学元素分布的相关性,以此讨论了巴罗地区过去450年环境气候变化。结果表明,大约1740年以前,巴罗地区为低海面寒冷时期。从1827年左右起气候显着变暖,其中1860年前后和1925年前后,气温较高;1935年和1969年前后气温较低。

关键词: 北极, 沉积地球化学, 气候, 环境

Abstract: The paper deals with ass emble feature and distribution of chemical elements in the borehole AB-67 covered a time span of past 450 years from Elson lagoon in Barrow of Arctic Alaska. The correlation between the contents of clay and organic matter and the concentration of chemical elements are described. The analysing data show that the concentrations of major elements(SiO2,Fe2O3),trace elements(Ni,Cu,Zn and Pb)and rare an drare-earth element s(v,Co,Ga,S e,Y,Zr,Li,N b et c.)are qu it e differen t betw een th e upper part(0—20cm in depth)and the lower part(20—60cm in depth)of the borehole AB-67.In the lower part(20—60cm)SiO2,Fe2O3,and A l2O3,account decreases by 76.24%,Fe2O3 and Al2O3 increase up t o 3.39%and 7.21%respectively,in dicat in gastrent hening of chemical weathering which resulted in leaching of SiO2 and enrichment of Al2O3 and Fe2O3.Concen trations of Cu,Pb,Zn and Ni below the depth of 20cm in the coreareless than 15mg/kg,15mg/kg,70mg/kg and 20mg/kg respectively,while abovet hedept hof 20cm in the corethey are roughly double increased. The variation tendency of trace elements are coincided to that of silt and clay as well as the organic matter with a coefficient of correlation of 0.80.An cluster an alysis of chemical elements shows that the rere and rare-earth elements(V,Co,Ga,Se,Y,Zr,Li,Nb etc.)and the trace elements(Cu,Zn,Pb,Ni,Cr)are in a group with close positive linear relationship with a coefficient R=0.95,which shows that the elements are absorbed by clay and colloid and can be carried in sus pended sediments and accumulated together in the lagoon.The trans portation and accumulation of chemical element group infer that the catchment basin in Barrow has been apparently affected by chemical weat hering and biogenic proces ses under relatively a warm climate since 1827. Based on the characters of sed imen tary geochemistry of the borehole AB-67,t he history of climatic and environmental changes in Barrow in the past 450 years can be reconst ructed as follows:(1)A stage with a relatively cold and dry climate and a low sea level occured prior to 1700;(2)It was becoming warm accompanied with a transgression f rom 1700AD to 1827;(3) From 1872 to 1994(eg.0—20cm in depth of the borehole AB-67),it was fluetuated warming accompanied by continuous transgression;in this period relatively cold appeared around 1935 and 1969.This figure coincides with the results obtained from the study of tree-ring in northern Fen noscandinavia and the study of icecore on the Tibet an Plateau.

Key words: Arctic Barrow, lagoon, sediments geochemistry, climate, environment

中图分类号: 

  • P595