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以我国华南地区高分辨率湖相-泥炭交互沉积序列为例,开展正构烷烃分子化石与孢粉记录的对比研究,探讨和分析了它们之间的异同性及其可能原因.结果表明,分子化石与孢粉不能完全对应起来,其难以像孢粉一样能鉴别出具有不同生态意义的生物科属,主要记录原地植被的变化过程,而孢粉反映的是区域性植被的平均信号.分子化石在植被种属的明确解释上可能要部分依赖于孢粉,反过来分子化石也有助于提高孢粉分析中科属种的鉴定能力.分子化石对细节变化的敏感度要优越于孢粉,其正构烷烃C31/(C27+C29+C31)等指标显著地捕捉到了H1,B/A,YD事件,以及约9850~9585和8590~7920calaBP两次早全新世的干凉事件,这些事件可与周边地区环境变化格局对应,响应了区域环境变化和全球气候突变事件.通过这一实例的对比研究,说明分子化石与孢粉的相互结合,可弥补二者之间的不足,有效验证和提高恢复气候、植被演化的分辨率和准确性.
Taking the high resolution sedimentary sequence of lacustrine-peat sediments in South China as an example, the contrastive studies of n-alkanes molecular fossils and sporopollen records were carried out, the similarities and differences between them and their possible causes were discussed and analyzed.The results showed that the molecular Fossils and sporopollen can not be completely matched, it is difficult to identify as biosphere genus with different ecological significance as sporopollen, mainly records the process of in situ vegetation changes, and sporo-pollen reflects the average signal of regional vegetation. Fossils may partly depend on sporopollen in the clear explanation of vegetation species, and molecular fossils in turn help to improve the identification ability of families in sporopollen analysis. The sensitivity of molecular fossils to details is superior to that of sporopollen, The indexes of n-alkanes C31 / (C27 + C29 + C31) captured the H1, B / A and YD events and the dry-cool events of the early Holocene about 9850-9585 and 8590-7920calaBP, Corresponding to the changes of the environment in the surrounding area and responding to the regional environmental change and the sudden change of the global climate.Through the comparative study of this example, it shows that the combination of molecular fossils and sporopollen can make up for the shortcomings between the two, Verification efficiency and improve the resolution and accuracy of recovery climate, vegetation evolution.