新疆伊犁塔克尔莫乎尔沙漠全新世晚期沉积微量元素反映的古气候变化  

Paleoclimatic Significance of Geochemical Elements from Takermohur Desert,Xinjiang since Late Holocene

作　　者：靳建辉[1,2] 李志忠[1,2,3] 陈秀玲[1,2] 凌智永[3] 曹相东[3] 王少朴[3] 

机构地区：[1]福建师范大学地理科学学院,福州350007 [2]湿润亚热带生态-地理过程教育部重点实验室,福州350007 [3]新疆师范大学地理科学与旅游学院,乌鲁木齐830054

出　　处：《沉积学报》2011年第2期336-345,共10页Acta Sedimentologica Sinica

基　　金：国家"十一五"科技支撑计划项目(编号:2007BAC15B07);新疆维吾尔自治区自然科学基金项目(编号:200821103)资助

摘　　要：在新疆伊犁塔克尔莫乎尔沙漠腹地,选择可克达拉剖面(TKP)进行光释光(OSL)测年、微量元素含量测定,通过不同化学性质微量元素含量变化以及元素比值的相关分析与因子分析,探讨微量元素迁移的气候环境意义,结合粒度参数和碳酸盐含量变化特点,重建了研究区3.71 ka BP以来的气候变化序列。结果表明:晚全新世以来研究区古气候经历多次相对冷湿(凉湿)和暖干波动变化。其中,3.71～3.06 ka BP,冷湿;3.06～2.78 ka BP,暖干;2.78～2.10 ka BP,凉湿;2.10～0.50 ka BP,冷湿;0.50 ka BP以来由凉湿转为暖干。在相对冷湿期发育古土壤,示湿型微量元素的含量增加;干暖期发育风沙层,示干型微量元素的含量增加。晚全新世以来,研究区气候变化与北疆各地其他气候记录有较好的对比关系,同时与中高纬西风带上风区的北大西洋区域气候变化存在明显的呼应关系。研究区微量元素迁移特点所指示的典型西风区气候变化模式,可能反映了全球气候变化的区域差异性对微量元素迁移过程的影响。Takermohur desert is located in Yili valley of west Xinjiang,which is also situated at semiarid desert geochemical environment in mid-latitude westerlies of northern hemisphere.In the center of the desert,we observed a continuously sedimentary profile（with 3.6m outcropped thickness） which is formed with alternative aeolian layers and paleosol layers.On this profile,we collected 72 samples with 5cm equal interval and 3 samples for OSL dating.In the laboratory,we tested 18 trace elements content with X-ray fluorescence and grain-size composition with laser particle sizer for all 72 samples.Also,we tested the content of CaCO3 and TOC of all samples.On this basis,we carried out correlation analysis and factor analysis for the content changes and assemblage of trace elements and the ratio of Sr/Ba.According to the different geochemical environment which is indicated by trace element migration with different geochemical properties and the ratio of characteristic elements,we discussed the paleoclimatic characteristics which are recorded by trace element shift and accumulation of different layer in the profile.Based on the OSL time scale,we reconstructed climatic sequence since 3.71 ka BP,which contrast the changes of grain-size composition,CaCO3 and TOC content and refer to the optimal cluster analysis of different parameters.On the whole,the climatic changes of late Holocene in research area could be divided into 5 stages： 3.71~3.06 ka BP,cold and humid;3.06~2.78 ka BP,warm and arid;2.78~2.10 ka BP,cool and humid;2.10~0.50 ka BP,cold and humid;0.50 ka BP to present,changed from cold and humid to warm and arid.During the cold-humid climatic period,paleosol developed,and grain-sizes of the layer are finer,and amount of CaCO3 and TOC increased.The accumulation of trace element such as Ti、P、Nb et.al which indicates the humid sediment environment increased,and the ratio of Sr/Ba is decreased.During the warm-arid climatic period,aeolian layers developed,grain sizes are coarse,amount of CaCO3 and TOC at a relative l

关 键 词：新疆 塔克尔莫乎尔沙漠 晚全新世 微量元素 地球化学 古气候 

分 类 号：P534.63[天文地球—第四纪地质学]