摘要
洞穴石笋碳酸钙 (盐 )δ13C的同位素记录表明 ,其与δ18O同位素记录一样 ,均能反映气候环境的冷暖旋回变化 ,也具有急速的突变事件记录。本文利用近期或古老的洞穴石笋碳酸钙 (盐 )δ13C的同位素组成 ,对桂林地区 4 4ka以来的大气CO2浓度进行了尝试性的估算 ,估算结果表明 ,它可与近期所测量的以及冰岩芯气泡组分分析和北方黄土碳酸盐δ13C估算的大气CO2 浓度值基本接近 ,可以进行相互对比 ,说明利用洞穴石笋碳酸盐δ13C同位素组成对大气CO2 浓度进行估算的方法是可行的。研究表明 ,洞穴石笋碳酸盐δ13C同位素的记录 ,对地质时期的冷事件具有独特的敏感性 ,特别是对新仙女木冷事件和北大西洋Heinrich的H1至H5冷事件反映较为明显 ,在干冷期δ13C同位素快速升高 ,总体上与大气CO2 浓度的变化呈反比 ,大气CO2 浓度的变化与全球性的气候波动大体一致 ,但存在明显的区域性变化特征。
The δ 13C isotopic record of stalagmite carbonate in caves shows that, like δ 18O isotopic record, it can reflect the cold and warm cyclic change of the climatic environment, and can also reveal the events of quick and sudden changes. This paper attempts to estimate the atmospheric CO 2 concentration since 44 ka in Guilin area by using the δ 13C isotopic composition of new and old stalagmite carbonates in caves. The experimental results show that it is basically close to the atmospheric CO 2 concentration of the recently measuring air and one of the compositional analyses of ice core as well as to the estimated value of the loess sediment carbonate in North China. The data obtained are comparable with each other. This demonstrates clearly that it is feasible to apply the δ 13C isotopic composition of stalagmite carbonate to estimating the atmospheric CO 2 concentration. The study indicates that the δ 13C isotopic records of stalagmite carbonate in caves have distinctive sensitivity to the cold events in the geological history, especially to the cold event of the Younger Dryas and H 1, H 2,H 3, H 4 and H 5 cold events of the Heinrich .The δ 13C isotope values of stalagmite carbonate in caves rise quickly in the dry-cold peroid, being totally in inverse proportion to the change of the atmospheric CO 2 concentration, which is consistent with the evolution of the global climate. Nevertheless, the characteristics of regional climatic change are also obvious.
出处
《地球学报》
EI
CAS
CSCD
北大核心
2001年第5期447-452,共6页
Acta Geoscientica Sinica
基金
袁道先院士主持的IGCP 4 48对比项目
科技部攀登特别资助项目"全球岩溶生态系统对比"(编号 :2 0 0 0 0 2 6)资助
