内蒙古中东部湖泊沉积记录的全新世以来的气候变化

发布时间：2018-03-28 23:07

本文选题：达里湖　切入点：浩来呼热古湖　出处：《中国地质大学(北京)》2017年博士论文

【摘要】：中国内蒙古东部位于东亚季风的北缘,对气候变化响应敏感,多年来是气候变化研究的热点地区,也积累了较多的研究资料。但目前的研究显示,全新世以来的气候序列仍有很多不一致的地方,需要依靠更多具有可靠年龄控制的高精度气候变化序列。为此,本论文选取内蒙古中东部的达里湖和浩来呼热古湖的湖泊沉积物为研究对象,通过代用指标的分析,并结合AMS14C测年和OSL年代的控制,重建该区域全新世以来的气候环境变化过程。本研究的主要结论和认识如下:(1)通过达里湖湖滨沉积剖面以及6级湖岸堤剖面,重建的环境演化过程显示:末次冰消期至新仙女木时期,湖泊水位波动频繁,新仙女木之后约12.3 cal ka BP水位下降;自早全新世至10.0 cal ka BP,达里湖水位逐渐升高达到1274 m左右的高度,显示降水增加的气候好转过程;10-6.6 cal ka BP为达里湖的高湖面时期,区域气候以暖湿为主,进入全新世最适宜期;6.6-1.0 cal ka BP达里湖水位开始下降,指示降水减少,气候逐渐干旱,至全新世晚期约4.9-4.6 cal ka BP,湖泊水位与全新世早期相当;1.0 cal ka BP以来湖泊水位急剧下降,区域环境恶化。(2)对浩来呼热古湖重建的气候环境演化过程显示:12.2-8.7 cal ka BP气候相对冷干,但在新仙女木事件结束后约11.3 cal ka BP气候开始缓和;8.7-4.6 cal ka BP气候温暖湿润,虽在7.1-6 cal ka BP期间有所恶化但又迅速恢复;4.6-3.7 cal ka BP气候温暖但较前一阶段偏干;3.7-2.2 cal ka BP气候又再次缓和,整体特征温暖湿润;2.2 cal ka BP以来气候恶化,区域环境相对冷干。(3)两个湖泊沉积的重建结果共同显示全新世早、中期区域气候主要受控于东亚季风的影响,而全新世晚期区域气候可能受西风带的影响更大。但在一些细节上仍存在一定的差异。(4)浩来呼热古湖的湖心沉积剖面记录了八次气候冷干事件,分别发生于0.3(LIA)、1.3、2.9、4.4、7.9、8.9、9.5和11.6 cal ka BP(YD)。其中的六次冷事件与北大西洋的冰伐事件具有较好的一致性。可能说明东亚季风系统气候变化与北大西洋地区相耦合。
[Abstract]:Eastern Inner Mongolia, located in the northern edge of the East Asian monsoon, is sensitive to climate change and has been a hot spot in climate change research for many years, and has accumulated more research data. There are still many inconsistencies in the climate sequence since the Holocene and need to rely on more high-precision climate change sequences with reliable age control. In this paper, the lake sediments of Dali Lake and Houlaigu Lake in the central and eastern part of Inner Mongolia are selected as the research objects, and the AMS14C dating and the control of the OSL age are combined with the analysis of the substitution index. The main conclusions and understandings of this study are as follows: (1) the main conclusions and understandings of this study are as follows: (1) through the Dali Lake shore sedimentary profile and the 6 grade shore embankment profile, The environmental evolution process of the reconstruction showed that the lake water level fluctuated frequently from the last ice extinction period to the new fairy wood period, and the water level of the lake decreased after 12.3 cal ka BP. From early Holocene to 10.0 cal ka BP, the water level of Dali Lake gradually increased to a height of about 1274 m, indicating that the climatic improvement process of precipitation increase (10-6.6 cal ka BP) is the high lake period of Dali Lake, and the regional climate is mainly warm and wet. In the most suitable period of Holocene, the water level of Lake Daly (6.6-1.0 cal ka BP) began to decrease, indicating a decrease in precipitation and a gradual drought of climate. By the late Holocene, about 4.9-4.6 cal ka BP, the water level of the lake had dropped sharply compared with that of 1.0 cal ka BP in the early Holocene. Regional environmental deterioration. 2) the evolution process of climate environment of Huregu Lake in Haolai shows that the climate of cal ka BP is relatively cold and dry, but the climate of 11.3 cal ka BP begins to moderate 8.7-4.6 cal ka BP after the end of the Xinxianmu event. Although it deteriorated slightly during 7.1-6 cal ka BP, it recovered rapidly from 4.6-3.7 cal ka BP, but the climate of 3.7-2.2 cal ka BP was mild again compared with the previous stage, and the whole climate deteriorated since 2.2 cal ka BP. The reconstruction results of the two lake deposits show that the regional climate was mainly controlled by the influence of the East Asian monsoon in the early Holocene. The late Holocene regional climate may be more affected by the westerly zone, but there are still some differences in some details. The results show that the six cold events are in good agreement with the ice felling events in the North Atlantic, which may indicate that the climate change of the East Asian monsoon system is coupled with the North Atlantic region, and that the climate change of the East Asian monsoon system is coupled with that of the North Atlantic region, and that there is a good agreement between the six cold events and the ice felling events in the North Atlantic Ocean, respectively, which indicates that the climate change of the East Asian monsoon system is coupled with that of the North Atlantic region.
【学位授予单位】：中国地质大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：P532

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