MIS3晚期查格勒布鲁剖面微量元素揭示的千年尺度气候变化  

Millennial-scale climate changes during the late Mis3 revealed by trace element in Chagelebu Section

作　　者：牛东风[1] 李保生[1,2] 蒋树萍[1] 舒培仙 郭亿华[3] 杨艺[1] 温小浩[1] 

机构地区：[1]华南师范大学地理科学学院,广东广州510631 [2]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,陕西西安710061 [3]广州地理研究所,广东广州510070

出　　处：《干旱区地理》2015年第4期719-727,共9页Arid Land Geography

基　　金：国家自然科学基金(41290254;41471159)

摘　　要：通过对巴丹吉林查格勒布鲁剖面时代上属MIS3晚期的地层层位(CGS3a层段)中14种微量元素的分析发现:除Co、Ba含量呈相反变化外,P、V、Cr、Mn、Ni、Zn、Pb、Y、Zr、Nb、Cu和As含量在风成沙丘砂中基本上表现为谷值,而在不同层位沙丘砂上覆的湖相中则相对为峰,构成与沉积旋回相应的元素变化旋回。元素在沙丘砂中呈现的谷值,主要揭示了干冷气候条件下东亚冬季风的侵蚀、搬运和堆积作用;在湖相中的相对富集,则与东亚夏季风盛行时暖湿气候背景下该地所处的特殊洼地地貌位置有关。元素旋回实际上代表的是东亚冬夏季风的气候变化旋回。分析结果显示:MIS3晚期剖面所在地至少经历了5次冬夏季风交替变化的气候旋回,反映了该时期我国沙漠地区的千年尺度气候变化。Based on the analysis of 14 trace chemical elements from the CGS3 a segment that corresponds to the MIS3 in the Chagelebu section of the Badain Jaran Desert,Inner Mongolia,China,the paper found that the contents of different trace elements vary,and even greatly. Their distribution and average values are as follows：P,ranging from 215×10^-6to 844×10^-6（average 480×10^-6）;V,35×10^-6-100×10^-6（69.5×10^-6）;Cr,50×10^-6-102×10^-6（72.1×10^-6）;Mn,214×10^-6-1 794×10^-6（616×10^-6）;Co 12.4×10^-6-23.8×10^-6（16.6×10^-6）;Cu,7.2×10^-6-47.5×10-6（22.7×10^-6）;Ni,28.2×10^-6-53.5×10^-6（39.8×10^-6）;Zn,20.6×10^-6-101.7×10^-6（56.7×10^-6）;Pb,9×10^-6-29×10^-6（18.3×10^-6）;As,0×10^-6-13.3×10^-6（2.7×10^-6）;Y,11.6×10^-6-29.6×10^-6（20.2×10^-6）;Zr,88×10^-6-230×10^-6（144.7×10^-6）;Nb 3.2×10^-6-11.4×10^-6（7.4×10^-6）;Ba,457×10^-6-689×10^-6（571.4×10^-6）,respectively. The trace elements display obvious regulations in different sedimentary facies,the contents of P,V,Cr,Mn,Ni,Zn,Pb,Y,Zr,Nb,Cu and As are lower in the dune sands,but higher in the lacustrine facies;while the contents of Co and Ba show opposite trend：higher in the dune sands,and lower in the lacustrine facies. The lower values of the trace elements in the dune sands mainly indicate the effect of erosion,transportation and accumulation of East Asia winter monsoon under the cold-dry climate condition;whereas,the enrichment in the lacustrine facie is related to the specially low-lying location under the warm-humid climate background of East Asia summer monsoon. Therefore,the paper suggests that the trace elements cycles actually represent the climate cycles in the alternations between the East Asia winter and summer monsoons. The CGS3 a segment has experienced at least 5 climate cycles of alternation in the East Asia winter and summer monsoons,which reveals that there exist millennium-scale climate changes in the overall warm-humid climate during the Late MIS3 period.

关 键 词：MIS3晚期 查格勒布鲁剖面 微量元素 千年尺度气候变化 

分 类 号：P467[天文地球—大气科学及气象学]