Initial ²³⁴U/²³⁸U Variation of Stalagmites:Implications for Paleoclimate Reconstruction

详细信息   

• 责任者：Yang Yan (School of Geographical Sciences ; Southwest University ; Chongqing ; 400715 ; China) ; Yuan Daoxian
• 刊名：Acta Geologica Sinica
• 出版年：2008
• 卷期：82(5)
• 关键词：石笋 ; stalagmites ; 古气候 ; paleoclimate ; 西南地区 ; South West China
• 页码：p.692-701
• 图表：illus., 2 tables, 48 refs.
• 分类号：1400
• issnNo：ISSN0001-5717
• isbnNo：CN11-1951/P

摘要

This paper focuses on the relationship between initial ²³⁴U/²³⁸U in stalagmites and paleoclimate reconstructions based on 272 precise ICP-MS ²³⁰Th data collected from nine big stalagmites in the Dongge Cave ( 108°5′E, 25°17′N ); Yamen Cave ( 107°54′E, 25°29′N ) and Lianhua Cave (109°32′E, 29°08′N) in southwestern China. The initial ²³⁴U/²³⁸U ratios in stalagmites have a parallel relation to δ18O records of SPECMAP and keep a negative relation to summer insolation for 25°N in long term records. The (²³⁴U/²³⁸U)0 in stalagmites fluctuated slowly during interglacial periods and intensively in glacial periods, during transitional stage between glacial and interglacial, the (²³⁴U/²³⁸U)0in stalagmites shifted sharply. The (²³⁴U/²³⁸U)0 in stalagmites records BA warm events and YD chill events from the Last Glacial to Holocene, which is consistent with the long term (²³⁴U/²³⁸U)0 records, with heavier ratioes of stalagmites during chilling events and lighter ratioes of stalagmites during warm events.