【作者】 温锐林； 肖举乐； 常志刚； 翟大有； 周朗； 许清海； 李月从； S.Itoh；

【Author】 Wen Ruilin~①Xiao Jule~①Chang Zhigang~①Zhai Dayou~①Zhou Lang~①Xu Qinghai~②Li Yuecong~②S.Itoh~③(①Key Laboratory of Cenozoic Geology and Environment,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029;②College of Resources and Environment Science,Hebei Normal University,Shijiazhuang 050016;③Paleo Labo Co.,Ltd.,Saitama 335-0016 Japan)

【机构】 中国科学院地质与地球物理研究所新生代地质与环境重点实验室； 河北师范大学资源与环境科学学院； Paleo Labo Co.,Ltd.,Saitama 335-0016,Japan；

【摘要】 文章详细分析了内蒙古呼伦湖HL06岩芯沉积的孢粉组合,基于AMS¹⁴C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和气温的变化历史。结果表明,11000～8000aB.P.,湖区植被以蒿、藜占优,为干草原景观,气候暖干;8000～6400aB.P.,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;6400～4400aB.P.,湖区旱生草本植物增加,降水减少,气温继续下降;4400～3350aB.P.,耐旱藜科植物大量生长,湖区荒漠化,气候极端干旱;3350～2050aB.P.,湖区草原植被有所恢复,降水略有增加,气温有所回升;2050～1000aB.P.,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。更多还原

【Abstract】 A sediment core recovered in the central part of Hulun Lake in north Eastern Inner Mongolia was analysed for pollen assemblage and a pollen-climate transfer function was developed using the method of weighted averaging partial least squares in order to reveal the history of changes in vegetation and climate over the lake region during the Holocene.The data indicates that dry steppe dominated the lake basin under warm and dry conditions during the early Holocene between ca.11000cal.aB.P.and 8000cal.aB.P.From 8000cal.aB.P.to 6400cal.aB.P.,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 6400cal.aB.P.to 4400cal.aB.P.,arid plants increased in the lake region and precipitation began to decline and temperature continued to decrease.The interval between 4400cal.aB.P.and 3350cal.aB.P.was marked by extremely dry and relatively cold conditions with Chenopodiaceae dominating the lake basin.Artemisia showed a recovery 3350～2050cal.aB.P.when a slight increase both in precipitation and in temperature occurred.During the period of 2050～1000cal.aB.P.,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 synarthropic 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 8000cal.aB.P.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.更多还原