新疆巴里坤湖全新世环境记录及区域对比研究

选择位于西风环流显著影响区的巴里坤湖作为研究对象,采用¹⁴C测年建立了巴里坤湖沉积剖面约9400cal.aB.P.以来的时间序列。对该湖泊剖面沉积物的矿物X射线衍射、自生碳酸盐稳定同位素、碳酸盐含量和粒度指标的综合分析表明,9400cal.aB.P.以来,巴里坤湖地区的气候环境变化大致经历了冷干（9400～7400cal.aB.P.）-暖湿（7400～5900cal.aB.P.）-暖干（5900～3100cal.aB.P.）-凉湿（3100～1100cal.aB.P.）-冷干（1100～500cal.aB.P.）-暖干（500cal.aB.P.以来）的气候变化过程,该过程基本上同周边区域的气候环境变化记录相一致。在3800cal.aB.P.左右,北疆地区的几个典型湖泊沉积记录序列都指示该时期气候环境发生了较为明显的转折,可能暗示了这一时期亚洲中部干旱区（至少在北疆地区）大气环流状况发生了重大调整。

HOLOCENE CLIMATE CHANGE RECORDED BY LACUSTRINE SEDIMENTS IN BARKOL LAKE AND ITS REGIONAL COMPARISON

Holocene climate change history in Western China,especially the westerly dominated areas has been poorly understood due to the lack of the reliable climatic records,while various reliable climatic records have generally shown the same model and process in the Asian monsoon dominated areas.The Barkol Lake at the northeast of Xinjiang is believed to be able to provide good Holocene regional climate records of the westerly dominated areas.A 250-cm sediment section has been obtained from the Barkol Lake in August,2004 in order to reconstruct the paleoclimatic and environmental changes.The section chronology since 9400cal.aB.P.was constructed from seven conventional radiocarbon dates using the bulk organic matter from different depth.Based on analyses of the chronology,the autogenetic carbonate stable isotopes,the carbonate contents,the grain size,and the X-ray diffraction(XRD)of the mineral,the climate change history of the Barkol Lake region during the last 9400cal.aB.P.was revealed as cold and dry-warm(9400～7400cal.aB.P.) and wet-warm(7400～5900cal.aB.P.) and dry-temperate(5900～3100cal.aB.P.) and wet-cold(3100～1100cal.aB.P.) and dry-warm(1100～500cal.aB.P.) and dry(500cal.aB.P.～Pre.).The climatic and environmental evolution records of Barkol lake were in good accordance with those of the adjacent regions.At about 3800cal.aB.P.,climatic indexes from typical lakes in northern Xinjiang all show a common transition,which imply that the atmosphere circulation above the arid regions in Central Asia,at least in the northern Xinjiang area,might had great modulations.However,further researches are still needed in order to better understand the climate change history and the precise modulation of atmosphere circulation in Central Asia in Holocene.