崔巧玉^1,,
赵艳^1,2
1. 中国科学院地理科学与资源研究所, 中国科学院陆地表层格局与模拟重点实验室, 北京, 100101
2. 中国科学院大学, 北京 100049

基金项目: 国家重点基础研究发展计划项目（批准号：2016YFA0600501）、国家自然科学基金项目（批准号：41572353和41690113）和中国科学院（A类）战略性先导科技专项项目（批准号：XDA20070101）共同资助


详细信息

作者简介: 崔巧玉, 女, 39岁, 助理研究员, 古生态学专业, E-mail:qiaoyu.cui@igsnrr.ac.cn

中图分类号: P941.78;P534.63⁺2;P532

收稿日期:2019-03-28
修回日期:2019-07-21
刊出日期:2019-11-30

Climatic abrupt events implied by lacustrine sediments of Arxan Crater Lake, in the central Great Khingan Mountains, NE China during Holocene

Cui Qiaoyu^1,,
Zhao Yan^1,2
1. Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101
2. University of Chinese Academy of Sciences, Beijing 100049


MSC: P941.78;P534.63⁺2;P532

--> Received Date: 28 March 2019
Revised Date: 21 July 2019
Publish Date: 30 November 2019


摘要
摘要:阿尔山天池是大兴安岭中部一个封闭的火山口湖，地处东亚夏季风尾闾区，是研究区域气候快速变化的良好载体。通过对阿尔山天池岩芯（深度243~100 cm，年代10.0~1.3 cal.ka B.P.）开展连续、高分辨率的XRF元素扫描和粒度分析，选取岩芯中12种含量较高且环境指示意义明确的地球化学元素开展相关分析及因子分析发现：全新世时段阿尔山天池湖泊沉积物中Sr、Rb、Zr、Fe、Ca、K、Ti、Si、S、Mn、Cl等元素变化一致且均与Cr元素变化趋势相反，其中Sr、Rb、Zr、Fe、Ca、K、Ti、Si等8个迁移积累型元素之间相关性较高，且为湖泊元素变化的主控因子，说明阿尔山天池湖泊沉积物中元素来源主要受外源碎屑物质的影响，湖泊沉积物元素变化主要决定于区域气候的干湿状况。基于精确的年代框架，通过阿尔山天池沉积物Ca/Ti，Cr/Ti，Fe/Mn，Rb/Sr和Fe/Ti元素比值、粒度数据，与同一地区的月亮湖TOC和乔木花粉百分比记录对比分析表明：大兴安岭中部地区全新世以来气候-环境和湖泊水位经历了温暖偏干-低湖水位期（10.0~7.3 cal.ka B.P.）、温凉湿润-高湖水位期（7.3~6.1 cal.ka B.P.）、温暖湿润-低湖水位期（6.1~4.3 cal.ka B.P.）、温凉湿润-高湖水位期（4.3~3.0 cal.ka B.P.）、温暖湿润-较高湖水位期（3.0~1.4 cal.ka B.P.）等5个阶段的演变；元素记录15次显著快速干旱气候事件，其中发生在7.8cal.ka B.P.、7.3cal.ka B.P.、6.9cal.ka B.P.、6.5cal.ka B.P.、6.3cal.ka B.P.、6.1cal.ka B.P.、5.5 cal.ka B.P.、4.2 cal.ka B.P.、3.8 cal.ka B.P.、3.6 cal.ka B.P.、3.0 cal.ka B.P.、2.6 cal.ka B.P.及1.8 cal.ka B.P.的13次干旱事件与已有大兴安岭地区其他钻孔记录均有较好的对应。此外，阿尔山天池湖泊记录中Fe/Ti元素比值与粉砂和粘土含量变化趋势基本一致，表明在东北封闭湖泊中Fe/Ti可作为湖泊细颗粒组分的良好代用指标。本研究表明湖泊沉积物高分辨率的XRF元素扫描分析在气候快速变化研究方面具有很大的潜力。
关键词: 元素地球化学/
湖泊沉积物/
气候突变/
全新世/
大兴安岭

Abstract:Arxan Crater Lake (ACL17C; 47.32°N, 120.41°E, 1280 m a.s.l.) is a closed crater lake situated in the middle of Great Khingan Mountains, NE China. The lake sediment honestly recorded climatic-environmental change in the study region due to its location on the margin of East Asian Summer Monsoon domain. Here, high-resolution and continuous XRF core scanning and grain-size analysis were carried out on the lake sediments of ACL17C (243~100 cm in depth, 10.0~1.3 cal.ka. B. P. in ages) to reveal the climatic abrupt events throughout the Holocene. Twelve geochemical elements, with consistent content and clear palaeoenvironmental signals, were selected to investigate the element characteristics by using correlation analysis and factor analysis. The results show that:(1) The element Sr, Rb, Zr, Fe, Ca, K, Ti, Si, S, Mn and Cl from ACL were displaying a similar variation pattern but element Cr showed a reverse trend; (2) Eight transport and deposition elements Sr, Rb, Zr, Fe, Ca, K, Ti and Si were well correlated, and contributed to 60% of total element variations which indicate the detrital inputs resulting from catchment run-off were the main source of element contents of ACL. Based on the 10 AMS¹⁴C dates, a precise chronological framework was established for ACL. Comparison of elemental ratios (Ca/Ti, Cr/Ti, Fe/Mn, Rb/Sr and Fe/Ti) and mean grain-size from ACL with records of TOC and tree pollen% from Moon Lake, reveals the Holocene climatic-environmental history in the central Great Khingan Mountains went through five stages, i.e. warm and relative dry climate with lower water-level of the lake (10.0~7.3 cal.ka B. P.), cooler and humid climate with high water-level (7.3~6.1 cal.ka B. P.), warm and humid climate with lower water-level (6.1~4.3 cal.ka B. P.), cooler and humid climate period with high water-level (4.3~3.0 cal.ka B. P.), warm and humid climate with relative high water-level (3.0~1.4 cal.ka B. P.). Furthermore 15 significant drought events were inferred by elements ratios, among which 13 drought events at ca. 7.8 cal.ka B. P., 7.3 cal.ka B. P., 6.9 cal.ka B. P., 6.5 cal.ka B. P., 6.3 cal.ka B. P., 6.1 cal.ka B. P., 5.5 cal.ka B. P., 4.2 cal.ka B. P., 3.8 cal.ka B. P., 3.6 cal.ka B. P., 3.0 cal.ka B. P., 2.6 cal.ka B. P. and 1.8 cal.ka B. P. are comparable with former studies carried out in Great Khingan Mountains using different climatic proxy. In addition, the good consistency of trends of Fe/Ti and the content of fine sand and clay at ACL suggest Fe/Ti may be used as a good proxy to estimate the content of fine gain-size at closed lakes in NE China. This study shows the potentials of application of high-resolution XRF core scanning on the study of rapid climatic and environmental changes.
Key words:element geochemistry/
lacustrine sediment/
climate jumps/
Holocene/
Great Khingan Mountains



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