| 北京平原区晚更新世以来有机碳同位素特征及其古环境意义 |
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| 引用本文：倪志云,杨桂芳,黄俊华,张晓瑾,程捷,尹功明.2011.北京平原区晚更新世以来有机碳同位素特征及其古环境意义[J].地球学报,32(2):171-177. |
| DOI：10.3975/cagsb.2011.02.05 |
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| 基金项目:中国地质大学地质过程与矿产资源重点实验室项目(编号: GPMR200605) |
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| 中文摘要:沉积物中的有机质稳定碳同位素已经广泛应用于重建古环境。本文通过对北京平原区昌平钻孔δ13Corg数值变化特征的分析, 结合格陵兰冰芯和深海氧同位素曲线对比, 揭示了北京平原区晚更新世以来古环境变化特征及千年尺度的气候变化事件, 初步探讨了其驱动机制。该钻孔δ13Corg值变化范围为-17.10‰至-26.18‰, 主要表现为暖期时偏正, 冷期时则偏负。据此, 北京平原区晚更新世以来的气候变化可划分出4个阶段: 末次间冰期(MIS5)气候温暖; 末次冰期早冰阶(MIS4)气候温和适度; 末次冰期间冰阶(MIS3)气候出现多次急剧的冷暖波动; 末次冰期盛冰期(MIS2)气候冷干, δ13Corg值偏负阶段出现了对应格陵兰冰芯记录的H1-H9冷事件, 代表了北京平原区晚更新世以来千年尺度的气候波动, 但不同地区的变化幅度有所不同, 这些变化可能与微地形、气象、水文等区域基本控制因素有关。 |
| 中文关键词:有机碳同位素 古气候 千年尺度 晚更新世 北京平原区 |
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| Organic Carbon Isotopic Characteristics of Beijing Plain Since Late Pleistocene and Their Paleoenvironmental Implications |
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| Abstract:The organic carbon isotopic composition of sediments has been widely used to reconstruct paleoenvironment. An analysis of the organic carbon isotope in Changping borehole of Beijing plain, in comparison with the results from Greenland ice core and deep-sea oxygen isotope records, revealed the paleoenvironmental changes at the millennium scale in Beijing plain since the Late Pleistocene and their possible driving mechanism. The values of δ13Corg range from -17.10 ‰ to -26.18 ‰, with higher isotopic values indicating warmer periods. Accordingly, four climatic stages are evident, i.e., the warm last interglacial period (MIS5), the mild early glacial step (MIS4), the fluctuated interglacial step (MIS3) and the cold and dry late glacial step (MIS2). The millennial scale climatic instabilities over the Late Pleistocene were represented by the occurrence of nine strong Heinrich events shown by lower organic carbon isotope values. One probable reason for the different onsets might have been the contribution of local underlying factors, with topographic, hydrographic, and meteorological patterns being the predominant controls. |
| keywords:organic carbon isotope paleoclimate millennium-scale Late Pleistocene Beijing plain |
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