小冰期气候的湖北石笋碳同位素记录  

Carbon Isotope Record in Stalagmites from Hubei during the Little Ice Age

作　　者：陈剑舜 张伟宏 陈仕涛[2] 邵庆丰[2] 赵侃[2] 尹敬文 朱丽东[1] CHEN JianShun;ZHANG WeiHong;CHEN ShiTao;SHAO QingFeng;ZHAO Kan;YIN JingWen;ZHU LiDong(College of Geography and Environment Science,Zhejiang Normal University,Jinhua,Zhejiang 321004,China;College of Geography Science,Nanjing Normal University,Nanjing 210023,China)

机构地区：[1]浙江师范大学地理与环境科学学院,浙江金华321004 [2]南京师范大学地理科学学院,南京210023

出　　处：《沉积学报》2020年第3期497-504,共8页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(41602350,41572340,41572345)。

摘　　要：研究季风区小冰期的结构特征和区域响应有助于深入了解季风系统与地球内外驱动力的耦合关系。利用湖北神农架永兴洞YX275石笋的7个230 Th年龄和120个碳同位素数据,建立了1360~1955 AD期间5年分辨率的石笋碳同位素序列。石笋δ13C与δ18O记录在长期趋势上有很好的对应关系,对小冰期气候响应明显,δ13C记录在大尺度季风环流影响下主要反映了局域湿度变化特征。δ13C序列在1453~1890 AD显著正偏,表明小冰期时湿度明显降低。此外,石笋δ13C与亚洲夏季温度、南方涛动指数和热带辐合带记录有较好的一致性,表明亚洲大陆夏季温度和太平洋水汽可能通过影响夏季风的强弱来调控湖北地区的湿度变化。在小冰期内部,δ13C记录在1450~1550 AD和1790~1830 AD出现进一步正偏,这些振荡分别对应于太阳活动的Spörer和Dalton极小期,暗示太阳活动减弱期对中国中部小冰期水文振荡的进一步调控作用。Studying the structural characteristics and regional response in the monsoon region during the Little Ice Age(LIA)is helpful in understanding the coupling relationship between the monsoon system and the earth's inter-nal and external driving forces.Using 7230Th ages and 120 carbon isotope data from the YX275 stalagmite of Yong-xing Cave,Hubei Province,we establish the carbon isotope time-series with a 5-yr-resolution from 1360-1955 AD.A close similarity between the long term trend of carbon and oxygen isotope records(δ13C andδ18O)indicates that theδ13C record responds to climate change during the LIA.Stalagmiteδ13C mainly reflects the local humidity varia-tion influenced by the large-scale monsoon circulation.Theδ13C values show a significantly positive shift from 1453-1890 AD,indicating that the soil moisture decreased significantly during the LIA.The stalagmiteδ13C record is con-sistent with the Asian summer temperature,the Southern Oscillation Index,and the mean position of the intertropical convergence zone(ITCZ),suggesting that the Asian continental summer temperature and Pacific Ocean water vapor may regulate the humidity variation in Hubei province by influencing the strength of the summer monsoon.During the LIA,theδ13C record was heavier in 1460-1550 AD and 1815-1865 AD.These fluctuations correspond to the Spörer and Dalton Minimums,respectively,implying that the solar activity weakening period further regulated the hydrologi-cal oscillations during the LIA in central China.

关 键 词：小冰期 石笋 碳同位素 局域水文 

分 类 号：P532[天文地球—古生物学与地层学]