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| 毛乌素沙漠东南缘全新世剖面光释光年代及古气候意义 | |
| 引用本文： | 马冀,岳乐平,杨利荣,孙蕗,徐永.毛乌素沙漠东南缘全新世剖面光释光年代及古气候意义[J].第四纪研究,2011,31(1):120-129. |
| 作者姓名： | 马冀 岳乐平 杨利荣 孙蕗 徐永 |
| 作者单位： | 西北大学大陆动力学国家重点实验室,西安 710069; 中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,西安 710075 |
| 基金项目： | 国家自然科学基金重点项目(批准号: 40802039)资助 |
| 摘 要： | 在毛乌素沙漠东南缘锦界地区发现的具有3层深棕色至黑色古土壤的全新世剖面,记录了至少3次大型沙地固定与活化的交替演化.在锦界剖面厚约5m的全新世地层中采集了10个光释光样品,利用石英光释光测年单片再生法(SAR),建立了锦界剖面全新世(>7.5-0.2ka)年代格架.结合粒度、磁化率气候变化代用指标和光释光年龄序列,得到... |
| 关 键 词： | 单片再生剂量法 全新世 气候记录 锦界剖面 毛乌素 |
| 收稿时间： | 2010-07-12 |
| 修稿时间： | 2010-09-16 |
OSL DATING OF HOLOCENE SEQUENCE AND PALAEOCLIMATE CHANGE RECORD IN SOUTHEASTEARN MARGIN OF MU US DESERT,NORTH CHINA |
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| Ma Ji,Yue Leping,Yang Lirong,Sun Lu,Xu Yong.OSL DATING OF HOLOCENE SEQUENCE AND PALAEOCLIMATE CHANGE RECORD IN SOUTHEASTEARN MARGIN OF MU US DESERT,NORTH CHINA[J].Quaternary Sciences,2011,31(1):120-129. | |
| Authors: | Ma Ji Yue Leping Yang Lirong Sun Lu Xu Yong |
| Institution: | State Key Laboratory of Continental Dynamics,North West University,Xi'an 710069; State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment, Chinese Academy of Sciences,Xi'an 710075 |
| Abstract: | Dune fields with several palaeosoil layers are common in marginal desert in Northern China and potentially reflect drought-moist variability in the Late Quaternary.A Holocene profile of aeolian deposits with alternating units of dune sands and sandy palaeosoils record dune building and stabilization at least three times in the Jinjie area(southeastern margin of Mu Us desert in China),which is specially located in loess-desert transitional region in response to East Asian monsoon alternation so as to likely archive millennial-scale patterns of palaeoenvironmental variability.Jinjie section (38.74°N,110.15°E; 1181m a.s.l),30km northwest of Shenmu County, is a ca.5-m-thick aeolian sandy profile (overlying layers of 2.5m modern dune and did not see bottom) with 3 layers of black or dark brown palaeosoils which correspond to three considerable dune fixations. In order to establish reliable timing of dune development,this study applied optically stimulated luminescence(OSL)dating techniques to the aeolian sediments features.10 luminescence samples obtained from this profile were dated using the quartz single aliquot regeneration(SAR)protocol.Combining with palaeoclimate proxies(e.g. ,grain sizes and magnetic susceptibilities),the records revealed as many as seven periods of significant rapid climate changes during the time intervals the palaeosoil layers deposited.The spatial and temporal extent of the data have allowed for correlations to be made with evidence from global climate changes.The first arid episode occurred before 7.5ka in the early Holocene,with widespread aeolian sand mobilization and sparse vegetation.During 7.5~3.9ka,climate turned to be warmer and more humid with the occurrence of thick palaeosoil layers in the lowest,at the same time with Holocene Optimum.When it comes to 3.9~2.9ka,the dune rebounded to reactive with strong winter monsoon,and the climate became arid again.The timing of widespread dune reactivation coincided with well-known 4ka event.The climate became warm and humid during 2.9~1.7ka,with lower magnetic susceptibility than the upper palaeosoil layer.Although the summer monsoon is weakened,the winter monsoon failed to become predominant.Climate fluctuated more frequently after 1.7ka with a warm climate episode during 1.0~0.5ka and an arid one around 0.2ka.It also revealed that the human significance of Holocene climate variability since 1ka ago.More importantly,the Holocene climate changes and evolution records from the Jinjie section could be correlated with the worldwide millennial-scale climate shifts,suggesting that the activity of East Asia monsoon in the Holocene may have directly been controlled or affected by global climate system.Several intervals coincide with major disruptions of civilization,revealing the human significance of Holocene climate variability at times. |
| Keywords: | Jinjie section SAR palaeoclimate record Mu Us desert Holocene |
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