摘要
本文根据ＲＭ孔上部６０ｍ２１０个样品的花粉分析结果，探讨了若尔盖地区２５万年以来的植被演替和气候变化。研究结果表明，若尔盖地区过去２５万年的植被演替和气候变化可划分为７个阶段。在约２５０－１９５ＫａＢ．Ｐ．（７阶段），植被以亚高山莎草草甸为主，气温和降水与现在接近。在１９５－１２８ＫａＢ．Ｐ．（６阶段）和３２－１１ＫａＢ．Ｐ．（２阶段），植被主要是荒漠草原，反映寒冷干旱的冰期气候，年平均气温比现在低５－６℃，年降水量仅为现在的６０－８０％左右。１２８－７１ＫａＢ．Ｐ．（５阶段）是过去２５万年中水热条件最好的时期，植被主要是亚高山暗针叶林和亚高山草甸，大部分时间的气温比现在高１℃左右，降水量稍高于现在；但在此阶段的气温和降水仍有较大的波动，５ｅ、５ｃ和５ａ阶段的气温和降水高于５ｂ和５ｄ阶段。７１－５８ＫａＢ．Ｐ．（４阶段）的植被主要是高山草甸为主，年平均气温比今低３－５℃，年降水量约为现在的８０％，在５８－３２ＫａＢ．Ｐ．（３阶段），早期植被以亚高山暗针叶林和草甸为主，晚期主要是亚高山禾草草甸，气温和降水均明显高于４阶段，在晚期气温呈非线性逐渐下降的趋势。
The study involves the vegetational succession and climatic changes during the last 250000 years in the Zoige region, based on pollen analysis of 210 samples from upper 60m of Core RM.In 250-195Ka B.P.,subalpine Cyperaceae meadow occurred, and the temperature and precipitation were close to that of the present.During 195.128Ka B.P.and 32-11Ka B.P,a desert-steppe was found indicating a cold and dry climate with an annual mean temperature 5-6℃ lower than the present and an annual Precipitation of 60-80% as compared with that of today.There existed subalpine dark coniferous forest and meadow with the best climatic condition during 128-71ka B.P.;the annual mean temperature was 1℃±higher and the annual precipitation was slightly higher than the present.However,there were still fluctuations of temperature and precipitation in this period.The temperature and precipitation were higher in stages 5a,5c,5e than in 5b and 5d.Alpine grass and Cyperaceae meadow appeared in 71-58Ka B.P.,indicating an annual mean temperature 3-5℃ lower than the present and a precipitation of 80% as compared with that of today.During 58-32Ka B.P.,the vegetation was subalpine dark coniferous forest and meadow in the early stage,when the temperature and precipitation were higher than the present in 71-58Ka B.P.;the vegetation was subalpine grass meadow in the late stage,when the temperature and precipitation showed a trend of non-linear drop.
出处
《微体古生物学报》
CSCD
北大核心
1996年第4期373-385,共13页
Acta Micropalaeontologica Sinica
基金
国家八五攀登计划青藏项目
