北极阿拉斯加巴罗地区现代环境的地球化学特征研究

ENVIRONMENT GEOCHEMICAL CHARACTERISTICS IN BARROW, ALASKAN ARCTIC

本文以北极阿拉斯加巴罗地区样品分析为依据，研究泻湖、淡水湖、河流、沼泽、土壤等的环境地球化学特征。结果表明，巴罗地区融冻物理风化作用强烈，化学风化和生物地球化学作用较弱，物质以机械搬运为主，Ｈ＋为地带性标型元素。地表水化学类型阴离子以Ｃｌ－为主，阳离子以Ｋ＋Ｎａ＋为主。现代沉积物、地表土壤、沼泽泥炭层有机质含量丰富，最高可达５０．０７％。大量元素ＳｉＯ２含量极高，稀有稀土元素、微量元素含量偏低，但Ｈｇ、Ｃｄ、Ｃｒ的含量相对较高。

Barrow is located on the arctic coastal plain at the northeast Alaska (71°20'N. 156°40'W),where Permafrost is well developed with a mean annual temperature of-12. 6℃. Therefore, the modern environmental processes are dominated by physical weathering (freezing and thawing) and segmentation which infuence on the characteristic of present tundra environmental geochemistry. Some 35 samples of water, soil and snow were collected from sea, lagoon, lake. stream and bog at Barrow in August-September, 1994. The preliminary results are as follows: (1) Chemical and bio-chemical processes also existed in such an extremely cold region, which may be caused by higher summer temperature. (2) H+ is a typomorphic element appeared in the Arctic tundra environment. (3) The major positive and negative ions are K++Na+ and Cl- in the aquatic environment, appearing in a distribution roder of decreasing from ocean to land, that is:stream water<bog water<fresh lake water<lagoon water<sea water.(4) Organic materials in tundra soils and surface deposits in lagoon and lake are comparatively high in case up to 50. 07% which may infuence the transport and accumalation of chemical elements.(5) The content of major element St is extremely high which ranges from 73. 87% to 90. 41%,and the contents of rare elements. rare-earth elements and trace elements are relatively low. However, the contents of Hg, Cd, Cr and comparatively high.