海南岛双池玛珥湖沉积正构烷烃记录揭示的中世纪暖期气候环境特征  

Climatic and environmental characteristics of the Medieval Warm Period revealed by n-alkane records in the Shuangchi Maar Lake,Hainan Island

作　　者：卢毅 薛积彬[1] 张永东 马欣璐 宋德卓 钟巍[1] Lu Yi;Xue Jibin;Zhang Yongdong;Ma Xinlu;Song Dezhuo;Zhong Wei(School of Geographical Sciences,South China Normal University,Guangzhou 510631,Guangdong,China)

机构地区：[1]华南师范大学地理科学学院,广东广州510631

出　　处：《地理科学》2024年第3期543-552,共10页Scientia Geographica Sinica

基　　金：国家自然科学基金项目(42071108,41671194)资助。

摘　　要：对采自海南岛双池玛珥湖的沉积岩芯(SCH17-04)进行了加速器质谱法(Accelerator Mass Spectrometry,AMS)^(14)C测年和正构烷烃组成的实验分析,据此探讨了中国热带北缘地区约775-1550年间的气候环境特征。结果表明,SCH17-04岩芯正构烷烃记录揭示了该湖沉积的有机质主要来自于陆生高等植物,也包含部分水生植物和菌藻类植物的输入;利用正构烷烃相关组分的比值发现,在中世纪暖期(Medieval Warm Period,MWP,约950-1350年)时,研究区草本植物比例明显增大,木本植物占比相对偏小,揭示出地处热带北缘的海南岛地区在中世纪暖期气候环境总体上较为偏干,而在黑暗时代冷期(Dark Ages Cold Period,DACP)晚期(约775-950年)和小冰期(Little Ice Age,LIA)早期(约1350-1550年),海南岛地区气候环境相对较为偏湿。区域对比分析发现,双池玛珥湖沉积正构烷烃记录与同处热带地区的雷州半岛湖光岩玛珥湖沉积、西沙群岛东岛湖泊沉积以及来自泰国的石笋记录等较为一致,都揭示了一个气候相对较为偏干的中世纪暖期,这可能跟同一时期热带辐合带(Intertropical Convergence Zone,ITCZ)南北迁移和热带雨带的扩张与收缩、太平洋东西部海区海表温度梯度变化等因素有关。With a focus on the Medieval Warm Period(MWP)and the Little Ice Age(LIA),the last millenni-um is a crucial period in the study of global climate change.In this study,a sediment core(SCH17-04)was col-lected from Shuangchi Maar Lake,Hainan Island,South China,and its n-alkanes proxies,including the ratios of Tree/Grass,Proportion of aquatic(Paq),Carbon Preference Index(CPI)and Average Chain Length(ACL)were determined.Based on the analysis of Accelerator Mass Spectrometry(AMS)^(14)C age and n-alkanes,the climatic and environmental characteristics of this region were reconstructed from 775 to 1550.The results showed that the proportion of long-chain n-alkanes was relatively high,while the proportion of medium-and short-chain n-alkanes was relatively low,suggesting that the organic matter inputs to the sediments of Shuang-chi Maar Lake over the last millennium were mainly dominated by terrestrial higher plants,with relatively small contributions from aquatic plants and fungi and algae.Based on the above indicators,the environmental changes of Shuangchi Maar Lake over the past millennium can be divided into three stages:1)In the late Dark Ages Cold Period,the gradual decrease in the Tree/Grass ratio and the significant increase in the ACL value in-dicated a gradual decrease in woody plants in the study area,indicating that the climatic environment of the study area was drier during this period.2)In the Medieval Warm Period,low Tree/Grass values and high ACL values indicated an increase in the proportion of herbaceous plants and a relative decrease in the proportion of woody plants in the study area,suggesting a drier climate during this period.3)In the early Little Ice Age,the increase in Tree/Grass values and decrease in ACL values indicated a gradual increase in the proportion of woody vegetation and a gradual decrease in the proportion of herbaceous vegetation,indicating a wetter cli-mate during this period.In addition,the n-alkane records of Shuangchi Maar Lake were consistent with other climate records revealed by

关 键 词：热带地区 正构烷烃 中世纪暖期 小冰期 

分 类 号：F532[经济管理—产业经济]