孢粉学定量方法在洞庭盆地第四纪古气候重建中的初步应用

Preliminary application of palynological quantitative method in the reconstruction of Quaternary paleoclimate in Dongting Basin

  • 摘要: 第四纪气候变化是当今地学研究热点之一。洞庭盆地位于长江中游,是华南地区最具代表性的第四纪沉积盆地之一,其古气候记录对理解区域乃至全球气候演变具有重要意义。然而,现有研究在时间分辨率和区域对比性方面仍存在不足。为此,本研究以湖南省常德市汉寿县两护村ZKC01钻孔的孢粉数据为基础,采用现代类比法进行定量分析,旨在重建洞庭盆地第四纪以来的古温度与古降水变化序列。研究结果表明,洞庭盆地第四纪气候经历了显著的阶段性变化,识别出北半球冰川作用的降温阶段(约2.6~2.5 Ma)、更新世早期的干旱期(约2.6~2.2 Ma)、杰拉期和卡拉布里雅期的两次超级间冰期(约2.2~2.0 Ma和1.6~1.5 Ma)、中梁赣冰期以及末次冰期等重大气候事件。这些发现不仅完善了洞庭盆地第四纪古气候演化的高分辨率记录,而且为深入探讨区域气候对全球变化的响应机制提供了重要依据。

     

    Abstract: Quaternary climate change has been currently one of the research hotspots in geoscience. Dongting Basin in the middle reaches of the Changjiang (Yangtze) River is one of the most representative Quaternary sedimentary basins in South China. Its paleoclimate records are of great significance for understanding regional and global climate evolution. However, available studies still face limitations in temporal resolution and regional comparability. We utilized pollen data from the ZKC01 borehole in Lianghu Village, Changde, Hunan Province, for quantitative analysis in the Modern Analogue Technique (MAT), to reconstruct the paleotemperature and paleoprecipitation sequences of the basin during the Quaternary. Results indicate that the Quaternary climate of the basin underwent significant phased changes, including the Plio-Pleistocene intensification of Northern Hemisphere glaciation (iNHG, approximately 2.6~2.5 Ma), an early Pleistocene arid period (approximately 2.6~2.2 Ma), two superinterglacial periods during the Gelasian and Calabrian stages (approximately 2.2~2.0 Ma and 1.6~1.5 Ma, respectively), and the Zhonglianggan Glaciation and the Last Glaciation. These findings not only refine the high-resolution record of Quaternary paleoclimate evolution in Dongting Basin but also provide critical insights into the response mechanisms of regional climate to global changes.

     

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