苏北盆地XH1钻孔中更新世以来的彩度指标记录及其气候环境变化

CHROMA INDEX RECORD OF CORE XH1 AT NORTHERN JIANGSU BASIN AND THE CLIMATE SINCE MID-PLEISTOCENE

  • 摘要: 苏北盆地是我国西部内陆与东部海洋之间的过渡地区,该地区的气候演变历史对揭示东亚季风的时空变化有着重要意义。对苏北盆地XH1钻孔中更新世以来沉积物的彩度指标Ca*b*的研究表明,Ca*b*对降水的变化反应敏感,可以用来指示东亚夏季风强度和气候暖湿程度的变化。结合磁化率、有机碳和孢粉指标,揭示苏北盆地中更新世以来经历了9个明显的气候冷暖干湿变化旋回,并且可以和深海氧同位素记录、黄土记录进行良好的对比,同时在某些阶段和长期演变趋势上又具有鲜明的区域特征。总体上,从中更新世中期开始苏北盆地变得越来越冷干,气候冷暖波动幅度增大,最后4个冰期旋回尤为醒目。

     

    Abstract: Northern Jiangsu basin lies in the transitional region from ocean to continent and its climate is dominated by the East Asian monsoon system.Reconstructing the evolution history of paleoclimate in this region will provide significant further understanding of the process, rule and evolution trend of the East Asian monsoon. A drilling core XH1 of 350 m at Xinghua in the basin was recovered to reconstruct its environment evolution history. The results show that chroma index of the upper part 90 m of core XH1 responds sensitively to variations of precipitation. It could be used to indicate the intensity of East Asian summer monsoon and the climate changes. The process of climatic evolution since mid-Pleistocene could be divided into 9 major cold-warm fluctuation cycles by researching chroma index record with toc and pollen proxy,which were well corresponding to the record of deep sea and loess, and also had apparent regional features of long-term evolution trend and some stages. Generally,in the middle stage of mid-Pleistocene,climate of northern Jiangsu basin became colder and drier. Range between cold and warm enlarged and last four glacial-interglacial cycles became more distinct.

     

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