安徽巢湖全新世湖泊沉积物磁化率与粒度组合的变化特征及其环境意义

通过对获取的巢湖湖泊沉积岩芯的磁化率与粒度组合特征的分析,结合孢粉及相邻其它区域的环境考古资料,得出该岩芯柱样所反映的环境变化信息.结果表明:(1)巢湖湖泊沉积物磁化率曲线在117 cm以下总体上比较平稳而略有下降,117 cm以上人类活动所导致的侵蚀作用加剧使得磁化率值异常升高;(2)本岩芯柱样117 cm以下样品的磁化率强度与粘土的百分比含量呈正相关,而与粉砂组分的百分比含量成负相关;(3)根据磁化率与粒度组合变化特征,结合孢粉分析及全新世以来区域气候变化背景,9870 Cal a B.P.以来的巢湖流域古气候环境演变可以划分6个不同的时期:9870～7000 cal a B.P.,气候呈温和略干的特点;7000～4750 Cal a B.P.,气候温暖湿润;4750～2170 Cal a B.P.,流域气候温和干燥,巢湖湖盆局部地区可能出露水面以上;2170～1040 Cal a B.P.,气候总体上温和湿润,但是冷暖波动明显;1040～200 Cal a B.P.流域处在温凉稍湿的时期,人类活动逐渐加强;200 Cal a B.P.至今,流域总体上处于相对温暖湿润阶段.

Characteristics and Environmental Significance of Magnetic Susceptibility and Grain Size of Lake Sediments since Holocene in Chaohu Lake,Anhui Province

A typical lake sediment core from Chaohu Lake was chosen for this study.The vertical distribution of magnetic susceptibility and grain size in the sediments was determined.Based on the analyses of magnetic susceptibility and grain size of the core samples from Chaohu Lake,the paper has probed into the characteristics and environmental significance of magnetic susceptibility and grain size.The results show that from 490 cm to 117 cm,the curves of magnetic susceptibility are stable on the whole,which dropped ...