摘要
大干坝洼地发育了一套晚更新世河湖相地层,富含孢粉,明显可分两段:两万三千多年前为茂密的亚热带山地森林,水青冈属一度占优势;两万三千多年后森林稀化,蕨类植物生长,尔后阳性树种恢复。这反映该地从大理间冰段(阶)向盛冰期过渡时,环境条件发生了跳跃式的变化。
In this paper,the division of the two pollen zones is discussed based on the results of pollen and spores analysis and ^(14)C dating in the Daganba area,Zhijin County,central Guizhou Province.Zone Ⅰ represents a forest of mixed evergreen-deciduous broad-leaved trees closed subtropic mountain and dominated by Fagus,Quercus,Cyclobalanopsis,Carpinus and Castanea (Castanopsis,Lithocarpus) together with Pinus,Tsuga and Abies till 23000 yr B.P.It stands for the Dali interstadial climate,cool and moist.Zone Ⅱ vegetation adopted dry climate.Du- ring the time from 23000 yr B.P.to the fullglacial period the forest cowered and the fern ex- tended.The pioneer trees such as Pinus,Betula began to grow towards the end of the dry pha- se.The genus Fagus is of great importance in studing ecology and geography of the flora. The retirement and growth of Fagus forest reveals the paleoenvironment changes.
