贵州威宁麻窝山岩溶盆地沉积物的微量元素特征及环境意义  

Trace Element Geochemistry of the Mawo Karst Basin in Weining County,Guizhou Province and Its Environmental Information

作　　者：吴月媛 吴攀[1] 曹振兴[2] 曹星星[1] 

机构地区：[1]贵州大学资源与环境工程学院,贵阳550025 [2]静冈大学创造科学技术大学院

出　　处：《地球与环境》2014年第6期710-718,共9页Earth and Environment

基　　金：国家重点基础研究发展规划"973"子项目(编号2006CB403202)"碳酸盐岩风化的生物地球化学过程与成土速率"

摘　　要：根据贵州威宁麻窝山岩溶盆地沉积物的剖面特征及微量元素特征的分析,探讨了该地区沉积环境的演化。对沉积剖面73个样品的分析结果表明,该区∑REE含量较高,稀土的配分模式为轻稀土元素明显富集、重稀土元素亏损的"右倾型",δEu负异常明显,样品的轻重稀土的分馏程度高。δCe反映了研究区沉积期的氧化还原状态,在HD、G1、N1、G5、N5、G6、N6表现为正异常或无异常,沉积时处于强氧化状态;其他层表现为负异常或无异常,表征沉积期的还原环境。微量元素含量变化特征、∑REE含量以及δCe值都说明了研究区古气候的干冷-温湿的旋回演化特征,自下而上可分为3个阶段,研究区经历2个明显的干冷-温湿大循环和3个干冷-温湿交替的小循环。According to the trace element geochemistry and characteristics of the sediments in the Mawo Karst Basin in Weining County,Guizhou Province,the authors discussed sedimentary environmental changes.63 samples of sediments were analyzed.The results indicated that the total rare-earth elements are quite high;there are significant differences between LREE and HREE;LREE is abundant,while HREE is defective.The LREE curve is obviously rightward heeling,while HREE is even,and Eu shows obvious negative anomalies.According to the characteristics of Ceanom,layers of HD,G1,N1,G5,N5,G6 and N6show that the basin is in an oxydic environment,whereas the rest of the layers show an anoxic environment.The performance of the trace elements,the total rare-earth elements,the characteristics of Ceanomindicate the climate change of the Mawo Basin,suggesting that there are three paleoclimatic periods,two obvious cycles and three minor cycles in alternating temperature and humidity.

关 键 词：微量元素 沉积环境 气候变化 麻窝山岩溶盆地 贵州 

分 类 号：P595[天文地球—地球化学]