摘要
全新世气候具有不稳定性,且存在着区域差异,在季风边缘区尤为显著.因此,本研究选取季风边缘区吉兰泰盐湖沉积物的孢粉记录并结合AMS14C测年结果,对该地区全新世的古植被演化及古气候变化历史进行了重建.结果表明,在全新世阶段,该地区植被类型未发生变化,以干旱的荒漠植被为主.早全新世(10.5 8.5 cal ka BP),以蒿属孢粉为主,伴随出现少量藜科、禾本科及麻黄属孢粉,蒿藜比(A/C比值)相对稳定(4.11左右),指示全新世早期气候逐步转湿的过程,在8.5 cal ka BP,蒿属孢粉数量下降且被藜科孢粉取代,指示一次明显气候干旱事件;中全新世(8.5 3.5 cal ka BP),蒿属孢粉含量增加及藜科孢粉含量降低,A/C比值在7.1 cal ka BP左右达到峰值,指示该地区中全新世气候最为湿润;晚全新世(3.5 cal ka BP至今),藜科孢粉含量增加且超过早全新世,A/C比值低至3.66,区域呈现明显的干旱化趋势.此外,结合吉兰泰盐湖沉积物矿物组成结果,发现中全新世湖泊沉积物中,钙芒硝大量出现,一定程度上指示降水量增多所带来的淡水注入,与孢粉指标指示该阶段湿润的结果一致.通过区域对比,发现吉兰泰地区在全新世时期的气候演化模式与东亚季风区具有较好的一致性,表明该地区受到东亚夏季风的影响较大,尤其是在中全新世,东亚夏季风增强,带来较多的降水,气候湿润.
Holocene climate is not stable,together with many regional differences,especially in the monsoon margin region.Hence,this study chose the pollen record preserved in the Jilantai Playa sediments from the monsoon margin region to reconstruct the evolution history of past vegetation and climate during the Holocene. The pollen analyses results indicate that the vegetation type didn＇t change in the study area during the Holocene. During the early Holocene（ 10.5-8.5 cal ka BP）,the samples contain high amount of Artemisia,together with relatively lower contributions of Chenopodiaceae,Poaceae and Ephedra. The A/C ratio was relatively low and stable（ about 4.11）,indicating a gradual increase in available moisture during the early Holocene. At 8.5 cal ka BP,the proportion of Artemisia pollen decreased sharply,which was replaced by Chenopodiaceae,indicating an apparent dry climate event. In the mid-Holocene stage（ 8.5-3.5 cal ka BP）,the content of Artemisia increased significantly while Chenopodiaceae decreased,resulting in the maximal A/C ratio at around 7.1-6.0 cal ka BP,pointing to the most humid interval during the Holocene. Then,in the late Holocene stage（ 3.5 cal ka BP to present）,the composition of Chenopodiaceae increased again and exceeded that in the early Holocene stage,with A/C ratio as low as 3.66,the region showed an obvious tendency of drought. Especially in the mid Holocene,the enhanced EASM brought sufficient moisture to the Jilantai region,forming the wettest condition during the whole Holocene,which is consistent with the mineral composition of the Jilantai Playa sediments,i.e. the appearance of Glauberite,during the mid-Holocene. Compared with regional climate records,the climate evolution pattern of Jilantai region is consistent with the East Asian Summer Monsoon（ EASM）,suggesting that the area is dominated by the EASM with the wettest period during the mid-Holocene.
作者
吴雅玲
王永波
刘兴起
于志同
倪振宇
WU Yaling;WANG Yongbo;LIU Xingqi;YU Zhitong;NI Zhenyu(College of Resource Environment and Tourism,Capital Normal University,Beijing 100048,P.R.China;College of Global Change and Earth System Science,Beijing Normal University,Beijing 100875,P.R.China)
出处
《湖泊科学》
EI
CAS
CSCD
北大核心
2018年第4期1166-1181,共16页
Journal of Lake Sciences
基金
国家自然科学基金项目(41502325
41372176)
首都师范大学研究生国际交流与联合培养项目(028175534000
011185516000)联合资助
关键词
吉兰泰盐湖
全新世
孢粉
古植被
东亚夏季风
Jilantai Playa
Holocene
pollen
paleovegetation
East Asian Summer Monsoon
