摘要
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117cm以下总体上比较平稳而略有下降，117cm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117cm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。
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 slightly; from 117cm to top, the increased human activity makes magnetic susceptibility increasing obviously. The magnetic susceptibility is positive proportional to the contents of fine sand, and reversal proportional to the contents of coarse sand and organic materials. By means of magnetic susceptibility and grain size analyses, combined with pollen and the background of global climate change, regional palaeoclimatic changes were divided into six periods since 9870 cal yr B. P. ： （ 1 ） mild and moderately dry period of 9870 -7000 cal yr B. P. ; （2） warm and humid period of 7000 - 4745 cal yr B. P. ; （3） warm and dry period of 4745 -2170 cal yr B. P. ; （4） mild and humid period of 2170 -1040 cal yr B, P. , and during which climate fluctuated acutely; （5） cool and moderately humid period of 1040 -200 cal yr B. P. , climate fluctuate gently; （6） mild and humid period of 200 cal yr B.P. to nowadays.
出处
《地理科学》
CSCD
北大核心
2008年第4期548-553,共6页
Scientia Geographica Sinica
基金
国家自然科学基金项目(批准号:40571162)
国家重点基础发展研究计划(国家973项目,课题编号:2003CB415201)
安徽省自然科学基金项目(批准号:050450401)资助
关键词
湖泊沉积
磁化率
粒度
环境演化
全新世
巢湖
lake sediments
magnetic susceptibility
Holocene
environmental changes
Chaohu Lake
