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通过对岱海深水区沉积柱样有机碳同位素、总有机碳 ,碳酸盐含量、频率磁化率等环境代用指标的分析 ,结合剖面的岩性特征和 2 1 0 Pb定年 ,初步探讨了岱海小冰期以来气候环境演化过程 ,结果表明 :在小冰期初期 740 - 540 a BP,以冷湿气候为主 ;在 540 - 4 80 a BP为寒冷干旱气候 ,可能为小冰期盛期 ;480 - 370 a BP,气候转温和 ,以凉偏湿气候为主 ;370 - 2 2 0 a BP,凉偏干气候为主 ;2 2 0 - 1 30 a BP,为小冰期末次冷波动 ,以冷干气候为主 ;1 30 a BP左右小冰期结束 ,其后进入现代有效降水略有增加的温偏湿气候 .本文环境代用指标揭示的小冰期前期的冷偏湿气候与同期的黄河中下游地区冷偏干气候不同 ,同时其揭示的最后两次冷期与根据冰芯、树轮、历史文献重建的十年平均温度确定的 1 4 50 ’s- 1 51 0 ’s、1 790 ’s- 1 890 ’s两次冷期极相吻合
Through the analysis of environmental proxy indexes of sedimentary column organic carbon isotope, total organic carbon, carbonate content and frequency magnetic susceptibility in the Daihai Deepwater Area, combined with the lithological characteristics of the section and the dating of 210 Pb, The results show that in the early period of the Little Ice Age, 740 - 540 a BP is dominated by cold and wet climate; in 540 - 480 a BP it is cold and arid climate, probably during the Little Ice Age; 480 - 370 a BP, temperate and temperate, with a cool and wet climate; 370-220 a BP, mainly cool and dry climate; 220-230-130 a BP, the last cold wave in the small ice age, And the climate is dominant.At the end of the Little Ice Age about 130 a BP, it entered a warm and wet climate with a slight increase of modern effective precipitation.The cold-wet climate of the Pre-Little Ice Age and the cold and wet regions of the middle and lower reaches of the Yellow River The dry climate is different, and the last two cold periods revealed by them are in agreement with the average temperature of 10 years reconstructed from ice cores, tree rings, historical documents, 1450-11500s, 1790s-1 890 ’s two cold period very consistent