Knowledge Resource Center for Ecological Environment in Arid Area
| 全新世呼伦湖区植被和气候变化的孢粉记录 | |
| 温锐林 | |
| 出版年 | 2010 |
| 学位类型 | 博士 |
| 导师 | 肖举乐 ; 许清海 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 未来全球变暖将对我国北方半干旱区生态格局和降水分布产生何种影响，是学术界关注的热点问题，全新世植被演替和气候变化研究将为回答这一问题提供基础数据。本文详细分析了内蒙古呼伦湖HL06岩芯沉积的孢粉组合，基于AMS 14C年代标尺，恢复了全新世湖区植被演变过程；并根据我国北方和蒙古表土孢粉数据和气象资料，建立了孢粉—气候参数转换函数，定量重建了呼伦湖区降水、气温的变化历史。结果表明，距今11,000–8000日历年前，湖区植被以蒿、藜占优，为干草原景观，气候暖干；8000–6400年前，湖区禾本植物扩张，山地桦林发育，降水显著增加，气温逐渐降低；6400–4400年前，湖区旱生草本植物增加，降水减少，气温继续下降；4400–3350年前，耐旱藜科植物大量生长，湖区荒漠化，气候极端干旱；3350–2050年前，湖区草原植被有所恢复，降水略有增加，气温有所回升；2050–1000年前，湖区蒿属植物减少，山地松林发育，气温降至全新世最低；最近1000年，藜科、禾本科等伴人植物大量出现，反映出人类活动对湖区自然环境的影响。全新世呼伦湖区气温变化在轨道尺度上受控于北半球太阳辐射量的变化，而在亚轨道尺度上可能与东亚夏季风强度有关。距今8000年前湖区降水较弱可能因为早全新世北半球高纬残存冰盖抑制了东亚季风雨带的北上，季风降水的千年—百年尺度波动与热带西太平洋海气相互作用密切相关。\n \n关键词：呼伦湖 HL06岩芯 孢粉 植被 降水 气温 东亚季风全新世 |
| 英文摘要 | More and more attention is being paid to the effect of possible global warming on the ecological pattern and precipitation variability in the semi-arid region of northern China in the near future. The solution to this problem is to study the history of past changes in the regional vegetation and climate during the Holocene. In this study, a sediment core (HL06) recovered in the central part of Hulun Lake in northeastern Inner Mongolia was analysed for pollen assemblage to reveal the Holocene process of vegetational evolution in the lake region. Moreover a pollen–climate transfer function was developed using the method of weighted averaging partial least squares based on a data set of surface pollen samples from northern China and Mongolia in order to quantitatively reconstruct the history of changes in the precipitation and temperature over the lake region. AMS 14C time series of the data indicates that dry steppe dominated the lake basin under warm and dry climatic conditions during the early Holocene between ca. 11,000 and 8000 cal yr BP. From 8000 to 6400 cal yr BP, grasses expanded in the lake basin and large-scale birch forests were developed in the surrounding mountains when the precipitation increased markedly and temperature decreased gradually. During the period of 6400 to 4400 cal yr BP, arid plants increased in the lake region and precipitation began to decline and temperature continued to decrease. The interval between 4400 and 3350 cal yr BP was marked by extremely dry and relatively cold conditions with Chenopodiaceae dominating the lake basin. Artemisia showed a recovery 3350–2050 cal yr BP when a slight increase both in the precipitation and in the temperature occurred. During the period of 2050–1000 cal yr BP, Artemisia herbs declined in the lake region and pine forests were developed in the mountains while the temperature dropped to the lowest within the whole Holocene. During the last 1000 yr, human activities might have had a significant influence on the environment of the lake region as indicated by the large-scale occurrence of anthrogenic plants of both Chenopodiaceae plants and grasses in the lake region. We suggest that temperature variations in the Hulun Lake region during the Holocene were controlled, on orbital scale, by changes in summer solar radiation in the Northern Hemisphere, but could be related, on suborbital scale, to the strength of the East Asian summer monsoon. The lack of precipitation over the lake region before 8000 cal yr BP would be attributed to the weakened summer monsoon resulting from the existence of remnant ice sheets in the Northern Hemisphere. Changes in the monsoon precipitation on millennial-to-centennial scales would be associated with the ocean–atmosphere interacting processes occurring in the western tropical Pacific.\n \nKeywords: Hulun Lake; HL06 core; Pollen; Vegetation; Temperature; Precipitation; East Asian monsoon; Holocene |
| 中文关键词 | 呼伦湖 ; 全新世 ; 植被 ; 气候 ; 孢粉 |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 第四纪地质学 |
| 来源机构 | 中国科学院地质与地球物理研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/286819 |
| 推荐引用方式 GB/T 7714 | 温锐林. 全新世呼伦湖区植被和气候变化的孢粉记录[D]. 中国科学院大学,2010. |
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