摘要
对晚更新世以来,伊犁地区与典型黄土高原地区黄土的稀土元素(REE)特征差异研究表明,伊犁盆地黄土剖面的REE特征不仅在含量上与典型黄土区的相似,分馏特征也基本相似,呈斜"L"型的分布模式,均发生轻、重稀土分异,分布曲线为负斜线,表现出中度的Eu负异常,Ce异常不明显,意味着晚更新世以来,不同地区黄土的物质来源具有一定的相似性。研究还发现,伊犁地区与黄土高原地区的稀土元素特征存在细微差异,昭苏黄土平均的稀土元素总量略高于昭苏古土壤平均值,与典型黄土区不同,这可能是由伊犁地区粉尘来源及其沉积环境的差异所致,且晚更新世以来不同区域黄土剖面REE特征参数三角图解也证实了这点。
Studies on the relations between the Asian aridification and the climate fluctuation in the northern hemisphere and the reconstruction of palaeoenvironment in arid region in north China have attracted extensive global attention in recent years,and more effective means are needed to be applied to reveal the specific mechanisms of them. As we all known,rare earth elements（ REE） with similar chemical properties and little changes during weathering transportation and diagenesis are widely used as the trace elements in studying the provenances of various sediments. REE characteristics are closely related to environmental change,so that REE can record the environment evolution in detail. Consequently,REE are widely used as the important indicators in studying paleoclimate. However,few studies on the characteristics and environmental significance of REE in loess in northwest inland area of China were carried out. The characteristics of rare earth elements in loess profiles in the Ili Basin and those in typical loess areas since the Epipleistocene were analyzed and compared. The results revealed that the average content of REE in loess profiles in the Ili Basin was similar to that in the typical loess profiles,and the REE distribution was in an inclined ＂L-shaped＂pattern. The main fractional characteristics were similar and characterized by LREE-enrichment and HREE-depletion,the distribution curves were negative oblique lines,and Eu performed a negative anomaly,but the anomaly of Ce was not obvious. Therefore,these loess profiles had the common characteristics,and loess was possibly originated from same sources. However,there were a few differences of the characteristics of REE in the loess profiles in different areas since the Epipleistocene,which was related to the existence of proximal sources of loess profiles in the Ili Basin,different sedimentation environment,and instability of upper air circulation.
出处
《干旱区研究》
CSCD
北大核心
2013年第6期1004-1012,共9页
Arid Zone Research
基金
黄土与第四纪地质国家重点实验室开放基金(SKLLQG1103,SKLLQG1113)
国家自然科学基金项目(41172166)
关键词
晚更新世
黄土剖面
稀土元素
黄土高原
伊犁盆地
新疆
Epipleistocene
loess profile
rare earth element
the Loess Plateau
Ili Basin
Xinjiang
