重庆羊子洞高分辨率石笋δ^(13)C记录的65-90ka BP气候变化  

A High-Resolution Stalagmite δ^(13)C Record About 65~90ka BP from Yangzi Cave,Chongqing

作　　者：黄帆[1] 杨勋林[1,2] 吕春艳[1] 李辰丝[1] 张月明[1] 

机构地区：[1]西南大学地理科学学院,重庆400715 [2]三峡库区生态与环境教育部重点实验室,重庆400715

出　　处：《西南大学学报（自然科学版）》2014年第5期166-173,共8页Journal of Southwest University(Natural Science Edition)

基　　金：国家自然科学基金资助项目(41072141;41272192);中央高校基本科研业务费重大项目(XDJK2012A003);西南大学博士基金资助项目(SWUB2007043)

摘　　要：利用三峡库区丰都羊子洞石笋(Y02)230 Th测年数据和碳同位素建立了65~90ka BP时段平均分辨率为46a的石笋碳同位素时间序列.羊子洞石笋碳同位素记录显示,季风变化在MIS5b向MIS5a转变过程中是渐变模式,并且D/O21事件呈现双峰结构不同于山宝洞石笋记录和万象洞石笋记录,这可能与羊子洞所处的地理位置和分辨率有关.石笋Y02的δ13 C记录并未记录72ka BP左右的降温事件.对石笋碳同位素进行功率谱分析发现,石笋Y02的δ13 C记录主要存在290,229,196,115,100和93a等周期,与太阳活动周期相吻合;Y02碳同位素记录与北半球太阳辐射曲线变化趋势一致,进一步证明了末次间冰期-末次冰期东亚季风区气候变化直接响应与北半球太阳辐射的假说.The carbon isotope time series during 65 ~ 90ka BP was reconstructed with the 230Th dating data and carbon isotope record of the Y02stalagmites in the Yangzi Cave in the Three Gorges Reservoir Area,Fengdu.The carbon isotope record of the Y02stalagmites in Yangzi Cave revealed that in the MIS5b-to-MIS5atransformation process the monsoon changed gradually and D/O21 was of a bimodal structure,which was different from the stalagmite records in the Sanbao Cave and the Wanxiang Cave and might be related to the location of the Yangzi Cave and the Y02resolution.Theδ13C record of Y02did not record the 72ka BP Toba volcanic eruption,so Toba volcano was not the dominant factor to the 72ka BP cooling event.Power spectrum analysis of the carbon isotope showed that 290,229,196,115,100and 93a cycles existed in theδ13C of Y02stalagmite record,which coincided with the solar activity cycle.The carbon isotope record of Y02appeared to be consistent with the change trend of the solar radiation curve in the northern hemisphere,which gave a further proof of the hypothesis that climate change of East Asian monsoon area is a direct response to changes of solar radiation in northern hemisphere during the transition from the last interglacial to the last glacial period.

关 键 词：石笋 碳同位素 72ka BP事件 三峡库区 

分 类 号：P532[天文地球—古生物学与地层学]