Climate Change during Little Ice Age with High-Resolution Stalagmite Record in the Three-Gorges Reservoir Area
详细信息
- 责任者：Yang Xunlin (Key Laboratory of Eco-Environments in Three Gorges Reservoir ; Ministry of Education ; School of Geography Science ; Southwest University ; Chongqing 400715 China) ; Chen Fahu
- 刊名：Scientia Geographica Sinica
- 出版年：2013
- 卷期：33(5)
- 关键词：小冰期 ; Neoglacial ; 古气候 ; paleoclimate ; 石笋 ; stalagmites ; 长江三峡 ; Yangtze Three Gorgees
- 页码：p.629-634
- 图表：illus., 1 table, 33 refs.
- 分类号：1400
- issnNo：ISSN1000-0690
- isbnNo：CN22-1124/P
摘要
A high-resolution oxygen isotope profile of the past 500 years was established with an average resolution of approximately one year,based on 7 high-precision230Th dates and 438 stable oxygen isotope ratios(δ18O) which were obtained from a stalagmite(NSM03) collected from Shuiming Cave,Chongqing City.So the variation of summer monsoon precipitation in the Three-Gorges reservoir area during the period of 1250-1750 A.D.was reconstructed.The δ18O value of the stalagmite NSM03 became heavier rapidly from 1280 A.D.,and reached to the heaviest around 1300 A.D.During the past 500 years,the Asian monsoon became weak rapidly,implying the Little Ice Age(LIA) starts.The trend of δ18O record from stalagmite NSM03 coincides with the other stalagmite records of the Asian monsoon region within the limits of dating error.Results showed that there were obvious interdecadal wet and dry fluctuations in LIA,especially during 1400-1650A.D.δ18O value of the stalagmite fluctuated dramatically indicating that monsoon precipitation was in frequently fluctuate period.Spectral analysis showed NSM03 δ18O sequence had significant cycle of 98,26,5,4,and 3 years(above the 99% confidence level).Similar periodicities of 98 and 26 years were proved by the δ18O record,further supporting the idea that solar changes were mainly responsible for Asian monsoon intensity changes in LIA;and 5,4 and 3 years were consistent with the 2-7 years standard cycle of El Nino-Southern Oscillation(ENSO),which implied that LIA climate variation had a close relation with ENSO.
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