Environmental Changes from Spore-Pollen Record of Mianyang Region over the Past 10000 Years

Abstract

依据M1孔孢粉组合特征及¹⁴C年龄数据,结合孢粉数理统计分析,重建了江汉平原沔阳地区一万多年来的古季风气候变迁序列.研究结果表明,该区气候经历了六个阶段的变化.6.7—4.4kaBP间.为水热配置最佳时期.夏季降水显著增多；3.9-12.7kaBP,气温有所下降,但有效湿度很高,为古云梦泽扩张时期,其湿度的增加既受锋面降水带的影响,同时与长江南移,河床迅速抬高有关.约6kaBP后,人类活动在本区就已存在,人与自然环境的关系由早期的依赖至适应再到改造的逐渐发展过程.;According to the analyses of spore—pollen assem blages. 1 4 C data. and numerical method,the palaeomonsoon climatic changes in Mianyang region,Jianghan plain·have been reconstructed in the past lO000 years. The result indicates that climate has undergone changes of six stages in this region. During 6.5-4.4kaBP,the climate came up to its optim um combination between heating and moisture,and the sum mer rainfall area caused m ore precipitation to is region.About 3.9-1.7kaBP, there was a ravid drop in the temperature.but the higher effective hum idity corresponding to the expansion of great lake of Yunmentze was reflected by both rainfalI area and the movement of the Yangtze River from north to south. After 6kaBP,hum an activity occurred in this region,undergoing the nature developing process from depending on the nature environm ent in the early period,to adapting to the environment after 3.5kaBP.and to changing environment after 9.7kaBP.