北极巴罗苔原区湖泊沉积的地球化学特征及其气候意义

GEOCHEMICAL CHARACTERISTICS AND ITS CLIMATIC SIGNIFICANCE IN THE BORECORE AB 32 FROM IKROAVIK LAKE IN THE TUNDRA BARROW,ARCTIC ALASKA

应用地球化学元素、地球化学淋溶系数及环境温度指标，研究了北极阿拉斯加巴罗热融湖Ｉｋｒｏａｖｉｋ钻孔岩芯ＡＢ－３２连续的高分辨环境记录。结合２１０Ｐｂ测年数据，指出巴罗地区气候、环境变化的历史状况是：１６００～１７３５年为寒冷、干燥时期；１７５０～１８３０年，气候变暖、变湿；１８３０年出现明显的地球化学转折界限，１８３０～１９９４年，气候较湿润温暖。１９６９～１９７０年前后，巴罗地区有一变冷阶段。ＡＢ－３２钻孔岩芯１８３０年左右表现的古地球化学特征与现代Ｉｋｒｏａｖｉｋ湖泊环境地球化学特征相吻合，并且和Ｅｌｓｏｎ泻湖ＡＢ－６７沉积岩芯反映的气候环境变化基本一致。

Paleoenvironmental record in the AB 32 sediment core from Ikroavik Lake in Barrow,Arctic Alaska was studied with geochemical assemblages,leaching factors and paleotemperature indicators. According to the geochemical characteristics of the borecore AB 32 and 210 Pb dating,climatic and environmental changes in Barrow,Alaska reconstructed are as follows:1) from 1600 to 1735 AD,it was a period of cold and dry; 2) from 1735 to 1830 AD,it was becoming warm and moist; 3) around 1830 AD,it was obviously with a demarcation of geochemical significance;1830-1994 AD,it was continuous more warm and moist,but appeared cold period around 1969-1970 AD. The paleogeochemical characteristics in AB 32 borecore around 1830 AD are similar with those of modern environment in Ikroavik lake and response to climatic and environmental changes reflected in the borecore AB 67 from Elson lagoon.