天堂寨泥炭地层的磁化率、Rb/Sr值及其反映的古气候意义  

Magnetic Susceptibility and Rb/Sr Ratio of Peat Stratum in Tiantangzhai and Its Significance of Palaeoclimate

作　　者：黄润[1] 朱诚[2] 王升堂[1] 

机构地区：[1]皖西学院城市建设与环境学系,安徽六安237012 [2]南京大学地理与海洋科学学院,江苏南京210093

出　　处：《地理科学》2007年第3期385-389,共5页Scientia Geographica Sinica

基　　金：国家自然科学基金(40271103);安徽省教育厅自然科学基金项目(2005KJ202)资助

摘　　要：天堂寨泥炭地层记录了大别山北亚热带地区全新世中晚期以来气候变化。通过对地层剖面磁化率、Rb／Sr值测定和分析，结合^14C测年，结果表明：大别山北亚热带地区中晚期以来气候变化可划分5个阶段：（1）5700～5050cal．aB．P．，气候暖湿为主；（2）5050～4300cal．aB．P．，以暖干为主，期间气候波动剧烈，气温出现过短暂而急剧的下降；（3）4300～2500cal．aB．P．，气候总体上处于相对冷湿状态，波动不大；（4）2500～1400cal．aB．P．，气温有所回升；（5）1400cal．aB．P．至今，气候冷干；至现代，气候又有所回升。磁化率和Rb／Sr比值可作为泥炭恢复古气候古环境的代用指标，但与黄土剖面中所指示的环境意义正好相反，即低磁化率和Rb／Sr比值指示气候湿热，高磁化率和Rb／Sr比值指示气候干冷。A typical peat profile of Tiantangzhai in the Dabie Mountains was chosen for this study. The vertical distribution of magnetic susceptibility and Rb/Sr elements in the sediments of the profile was determined. Its implication for the palaeoclimatic change of the north subtropics in the Holocene were discussed. By means of magnetic susceptibility and Rb and Sr concentration analyses, combined with ^14C dating, regional palaeoclimatic changes were divided into five periods since the middle and late Holocene ： （ 1 ） warm-wet period of 5700 - 5050 cal. a B. P. ; （2） warm-dry period of 5050 - 4300 cal. a B. P. , and during which climate fluctuated acutely, dining which abrupt climatic change occurred in 4600 - 4500 cal. a B. P. ; （3） relatively cool-wet period of 4300 - 1400 cal. a B. P. , climate fluctuated gently; （4） relatively warm-dry period of 1400 - 800 cal. a B. P. ; （5） cool-dry period from 1400 cal. a B.P. to nowadays, but temperature ascends again in modem times. Magnetic susceptibility and Rb/Sr ratio can be used as palaeclimatic proxy to identify peat records. Low magnetic susceptibility and Rb/Sr ratio indicate cool-dry climate condition, by contraries, high magnetic susceptibility and Rb/Sr ratio indicate warm-wet climate condition.

关 键 词：泥炭地层 磁化率Rb/Sr值 古气候 大别山天堂寨 

分 类 号：P532[天文地球—古生物学与地层学]