贵州梵净山九龙池一万年来的植被和气候变化

The Changes of Vegetation and Climate of Jiulongchi Section of Fanjingshan Mountain in Guizhou Since 10000 Years Ago

九龙池剖面是梵净山顶上的一个洼地剖面,深6.05m,未达基岩。采样112块,孢粉分析鉴定获得孢粉24539粒,有75个科属,以木本花粉为主,其次为蕨类孢子,草本少。根据孢粉组合及^(14)C年龄,该剖面为一万年来的沉积物。其古植被、古气候可分为三个发展时期:(Ⅰ)距今8100—10000年左右为少量落叶阔叶树及较多蕨类组成的疏树蕨类——不很繁茂的落叶阔叶林(林下蕨多)。气候由温凉—稍转温暖。(Ⅱ)距今1300—8100年左右,阔叶林繁盛时期,植被由落叶阔叶树为主的常绿、落叶阔叶混交林——常绿阔叶树为主的常绿、落叶阔叶混交林——落叶阔叶树为主的常绿、落叶阔叶混交林——落叶阔叶林。气候相应由温暖—温暖湿热—温暖—温暖偏凉。(Ⅲ)距今1300—900年左右,以松、栎为主的针阔叶混交林及喜冷湿的莎草较多,气候温暖偏凉湿。 笔者等认为,其气候期的划分(Ⅰ)代表前北方期一北方期,(Ⅱ)代表大西洋期—亚北方期—亚大西洋期(Ⅲ)代表亚大西洋期后的气候。

Jiulongchi section is a depression one at the top of Fanjing Mountain, Which is 6. 05m and doesn't reach the basic rock. Through sporopollen analysis, 24539 sporo-pollen grains have been gained from 112 samples collected, of which there are 75 families and genera, with woody pollens being more, pteridophyta pollens the next and herb pollens less. According to the sporopollen associations and 14C ages, the sediments of the section are those of 10000 years. The palaeovegetation and palaeoclimate of the section can be divided into three developing stages. I. During the Years from about 8100 to 10000, the vegetation was formed by sparse deciduous broadleaf trees and more pteridophyte (with more pteridophyte under the trees). The climate was becoming from warm cool to warm. II. During the years from about 1300 to 8100,the broadleaf trees were growing densely and the vegetation was formed by forests mixed mainly with deciduous broadlea ftrees and some evergreen broadleaf trees -forests mixed mainly with evergreen broadleaf trees and some deciduous broadleaf trees- forests mixed mainly with deciduous broadleaf trees and some evergreen broadleaf trees- deciduous broadleaf forests. The climate was becoming from warm to warm moist-warm warm cool. III. During the years from 1300-900,the vegetation was formed by deciduous broadleaf forests mixed mainly with Pinus and Quexcus as well as more pteridophyte. The climate was becoming from warm to cool moist. The authors think that the first division of the climate represents Preboreal Age-Boreal Age, the second Atlantic Age-Subboreal Age-Subatlantic Age and the third Late Subatlantic Age.