A Late Pleistocene-Holocene lacustrine record from Lake Manas, Zunggar (northern Xinjiang, western China)
A Late Pleistocene-Holocene lacustrine record from Lake Manas, Zunggar (northern Xinjiang, western China)
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DOI：
10.1016/0031-0182(95)00037-2
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发表时间：
1996-02
期刊：
影响因子：
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通讯作者：
T. Rhodes;F. Gasse;R. Lin;J. Fontes;K. Wei;P. Bertrand;E. Gibert;F. Mélières;P. Tucholka
中科院分区：
文献类型：
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作者：
T. Rhodes;F. Gasse;R. Lin;J. Fontes;K. Wei;P. Bertrand;E. Gibert;F. Mélières;P. Tucholka
通过对玛纳斯湖3个5 m长的岩心的研究，得到了新疆北部准噶尔沙漠晚第四纪古气候信息。对沉积物的矿物组成、碳酸盐、有机质、花粉和硅藻的稳定同位素含量进行了分析，以帮助重建该地区的环境演化。年表由9个碳酸盐或有机物的AMS14C日期提供。该记录表明，晚更新世潮湿时期（距今37,000-32,000年），该时期之后是末次盛冰期的极端干旱时期。早-中全新世的记录表明，中国西部的气候条件普遍比今天湿润，这一点在之前的研究中已得到证实。然而，我们的研究结果表明，全新世时期相当复杂。经过约12,000年B.P.的小湿/暖脉冲后，最重要的环境变化记录在约10,000年B.P.，它导致了集水区草原植被覆盖的建立，并形成了持续约4000年的永久湖泊。河流沉积发生在距今约6000年至4500年之间，与植被生长所需水分的减少相吻合。第二次湖泊事件记录于公元前4500年至2500年，尽管花粉记录和碎屑有机质的突然涌入表明在公元前3800年至3500年左右发生了短期干旱事件。最近2500年表明气候不稳定，玛纳斯湖的高盐条件逐步建立。
Information on the Late Quaternary palaeoclimate in the Zunggar desert (northern Xinjiang) is deduced from the study of three 5-m long cores taken from Lake Manas. Analyses, including the mineralogical composition of bulk sediments, stable isotope contents of carbonates, organic matter, pollen and diatoms, were performed to help reconstruct the environmental evolution of the area. The chronology is provided by 9 AMS14C dates done on carbonates or organic matter. The record suggests a Late Pleistocene humid episode radiocarbon-dated at 37,000–32,000 yr B.P. This episode is followed by a period of extreme aridity, attributed to the Last Glacial Maximum. The Early-Mid Holocene record indicates conditions generally wetter than today, as previously established for western China. However, our results show that the Holocene period is rather complex. After a minor wet/warm pulse estimated to be around 12,000 yr B.P., the most important environmental change is recorded at ≈ 10,000 yr B.P. It led to the establishment of a steppic vegetation cover in the catchment, and of a permanent lake which lasted ≈ 4000 years. Fluvial sedimentation took place between about 6000 and 4500 yr B.P., and it coincided with a decrease in moisture availability for vegetation growth. A second lacustrine episode is recorded from about 4500 to 2500 yr B.P., although the pollen record and a sudden influx in detrital organic matter suggest a short-term dry event around 3800-3500 yr B.P. The last 2500 years show climate unstability and the step-wise establishment of hypersaline conditions in Lake Manas. The major post glacial environmental changes appear to be roughly in phase with those observed in Tibet.