Knowledge Resource Center for Ecological Environment in Arid Area
| 新疆乌伦古湖记录的西风区全新世气候环境演化 | |
| 其他题名 | Holocene Climate Change in Westerly Area Inferred from Lake Sediments of Wulungu Lake，Xinjiang Province，China |
| 蒋庆丰 | |
| 出版年 | 2007 |
| 学位类型 | 博士 |
| 导师 | 沈吉 |
| 学位授予单位 | 中国科学院南京地理与湖泊研究所 |
| 中文摘要 | 西风区是联系北大西洋和亚洲季风两大气候区的纽带，对其研究可获得不同气候系统之间的关系并揭示其相互作用机制，这对全球气候变化驱动机制研究具有重要意义。全新世是地质历史上最新近的一个阶段，其气候变化过程和机制，特别是气候快速突变事件的深入研究对预测和了解未来全球气候环境变化趋势、评价人类未来的生存环境具有重要意义和参考价值。乌伦古湖是我国西北内陆干旱区最北端的湖泊，受西风气候影响最为显著，特殊的地理位置使其沉积物可以敏感、完整地记录西风区全新世气候环境的变化过程。本文利用210Pb、137Cs及AMS14C等测年技术，在建立可靠的地层年代序列基础上，对采自乌伦古湖和吉力湖沉积中心的湖泊岩芯进行了孢粉、粒度、有机质含量及有机碳同位素以及介形虫组合及其壳体氧碳同位素等多气候环境代用指标的实验分析，重建了全新世千-百年尺度和百-十年尺度岩芯所记录的区域气候环境的演化过程，通过广泛的区域对比分析，初步得到了西风区全新世以来的气候环境演化模式。\n 全新世以来乌伦古湖地区千-百年尺度上的气候变化大致经历了10.0～7.6cal.kaBP，温干；7.6～5.2cal.kaBP，暖湿；5.2～1.2cal.kaBP，温湿；1.2cal.kaBP以来凉干的变化过程。伴随气候的变化，湖泊曾出现明显的湖面上升（7.6～5.2cal.kaBP和3.6～1.2cal.kaBP）和退缩（5.2～3.6cal.kaBP和1.2～0cal.kaBP）变化。吉力湖2500年以来百-十年短时间尺度上的研究表明，区域气候环境变化大致经历了2.5～1.3cal.kaBP的温湿和1.3cal.kaBP以来的冷干，很好的验证了长时间尺度上重建的气候环境变化。乌伦古湖沉积记录的气候环境演化与周边区域环境变化记录和其它地质历史文献记录有很好的一致性，响应了区域环境变化和全球气候突变事件。\n 通过与国内外西风区和季风区湖泊沉积记录的对比，初步确认本区全新世以来气候环境变化与西风模式相吻合。西风区全新世以来的气候环境演变模式与季风区早中全新世（10～6cal.kaBP）湿润，中晚全新世干旱的模式显著不同，表现为该区早全新世（10～7.6cal.kaBP）气候干旱，湖泊水位较低，中晚全新世（7.6～1.2cal.kaBP）气候偏湿，区域降水增多，晚全新世晚期（1.2～0cal.kaBP）气候干旱，湖泊水位下降。 |
| 英文摘要 | As a link between the climats of North Atlantic and Asian monsoon, westerlies are the ideal place to study the relationship and interaction mechanism among different climate systems and play an important role in the study of mechanism of globe climate change. Holocene is the latest stage in geology history. Its climate change process and mechanism, especially abrupt climate events will help us understand the trend of globe warming better and evaluate the living environment to human beings in the future. Wulugu Lake，lied in the northest part of northwest dry land area in China, is strongly influenced by westerlies. The special geographic location makes the sediments from Wulungu Lake record the process of climatic variation of westerlies area sensitively during the Holocene. Based on the precise chronology through the 210Pb, 137Cs and AMS 14C dating and analyses of pollen, TOC, TN, δ13Corg, ostracod assemblages and its shell stable isotopes, the thesis presents the multi-proxy sequences and discusses paleoclimatic and paleoenvironmental changes during Holocene from a 225-cm-long sediment core from Wulungu Lake and a 80-cm-long sediment core from Jili Lake located in westerly area of China. The Holocene climate mode in westerly area is also discussed preliminarily. \n Holocene climate pattern in Wulungu Lake area on thousand-hundred years scale as follows: 10.0～7.6cal.kaBP，temperate and dry；7.6～5.2cal.kaBP，warm and wet；5.2～1.2cal.kaBP，temperate and moist；1.2～0cal.kaBP，cool and dry. With the climatic change, Wulungu Lake experienced two obvious retreat（5.2～3.6cal.kaBP and 1.2～0cal.kaBP）and transgression（7.6～5.2cal.kaBP and 3.6～1.2cal.kaBP） change. On the hundred-ten years scale, the temporal sequence of sedimentary cores retrieved from Lake Jili since 2.5cal.kaBP was established. The climatic changes experienced two stages：warm-wet climate during 2.5～1.3cal.kaBP and cold-dry climate during 1.3～0cal.kaBP. It validates the reliability of reconstructed climate and environment changes on thousand-hundred scale. The records of climatic and environmental evolution from Wulungu Lake area were in good accordance with those from adjacent areas. \n In contrast to other lake sediments records in westerly and monsoon area, the thesis recognizes that the climate changes inferred from lake sediments of Wulungu Lake followed the westerly Holocene climate change mode primarily. Other than monsoon Holocene climate change mode, which was wet in early-middle Holocene（10～6cal.kaBP）and dry in middle-late Holocene, westerly Holocene climate change mode was that dry climate and low lake level in early Holocene（10～7.6cal.kaBP），wet climate and high lake level in middle-late Holocene（7.6～1.2cal.kaBP）and dry climate and decreased lake level in late Holocene（1.2～0cal.kaBP）. |
| 中文关键词 | 乌伦古湖 ; 西风区 ; 全新世 ; 气候环境演化 |
| 英文关键词 | Wulungu lake westerly area Holocene climatic and environmental change |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 自然地理学 |
| 来源机构 | 中国科学院南京地理与湖泊研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/286571 |
| 推荐引用方式 GB/T 7714 | 蒋庆丰. 新疆乌伦古湖记录的西风区全新世气候环境演化[D]. 中国科学院南京地理与湖泊研究所,2007. |
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