对天目山千亩田2个泥炭剖面的研究显示,样品中Rb和Sr含量变化呈现出较好的正相关性,Rb/Sr比值与总有机碳含量(TOC)、烧失量和腐殖化度等指标有很好的相关性。Rb/Sr比值和Rb、Sr含量对古降水有指示意义,三者结合可用来重建过去气候的干湿变化。千亩田泥炭剖面Rb/Sr比值和Rb、Sr含量详细记录了晚全新世以来的气候变化,表明其大体存在3个阶段:4. 1~3.2 cal. ka B. P.,季风降水出现大幅下降,气候向干旱演变;3. 2~1.2 cal. ka B.P.,气候干冷,且有频繁波动;1. 2 cal. ka B. P.以来,气候呈现出向湿润变化的趋势,但伴有大幅波动,其中包含了1.2~0.9 cal. ka B.P.的中世纪暖期暖干气候以及0.6~0.3 cal. ka B. P.的明清小冰期冷湿气候。千亩田泥炭Rb/Sr比值和Rb、Sr含量记录的气候变化与东亚季风区中其他地区的多种高分辨率气候记录具有一致性,表明其共同响应了东亚季风的变迁。
英文摘要:
Research on the two peat profiles at Qianmutian shows that the Rb and Sr contents and Rb/Sr ratios are correlated with TOC、loss-on-ignition and humification combined with Rb/Sr and Rb and Sr contents can be used as credible proxy indices of wet and dry changes in the past in this region. In humid conditions in the Tianmu Mountains. Sr is leached, leading to grater Rb/Sr ratios. Thus, Rb/Sr ratios can be used as a credible proxy to infer wet vs. dry conditions and past climatic conditions. Rb/Sr ratios and Rb and Sr contents in late Holocene peat profiles in Qianmutian of Tianmu Mountains indicate that there are three stages of climate changes: 1) monsoonal precipitation dropped severely during 4. 1-3. 2 cal ka BP and climate became increasingly cold and dry; 2) cold and dry climate prevailed during 3. 2-1. 2 cal ka BP, but with frequent fluctuations; 3) the climate became warmer and more humid since 1. 2 cal ka BP but with large perturbations, including the Medieval Warm Period (1. 2-0. 9 cal ka BP) and the Ming-Qing Little Ice Age (0. 6-0. 3 cal ka BP). Our data and previously published records in other Southeast Asia areas show that local climate changes are recorded by Rb/Sr ratios and Rb and Sr contents.