重庆南川晚二叠世凝灰岩的元素地球化学特征  

Geochemical Features of the Late Permian Tuff in Nanchuan District, Chongqing,Southwestern China

作　　者：田和明[1,2] 代世峰[2] 李大华[1,3] 刘东[1,3] 邹建华[1,3] 李甜[1,3] 

机构地区：[1]外生成矿与矿山环境重庆市重点实验室(重庆地质矿产研究院),重庆400042 [2]中国矿业大学(北京)煤炭资源与安全开采国家重点实验室,北京100083 [3]煤炭资源与安全开采国家重点实验室重庆研究中心,重庆400042

出　　处：《地质论评》2014年第1期169-177,共9页Geological Review

基　　金：国家973课题(编号2014CB238902);国家自然科学基金资助项目(编号40930420和41272182)的成果

摘　　要：运用电感耦合等离子体质谱(ICP-MS)、X射线荧光光谱(XRF)、X射线衍射(XRD)、带能谱的扫描电镜(SEM-EDX)等方法对重庆南川晚二叠世凝灰岩的元素地球化学特征进行了研究。研究发现,凝灰岩中富集Al、Ti、Li、Cu、V、Cr、Co、Ni、Nb、Ta、Zr、Hf、Ga、Sc、Th、U和稀土元素(REE),其中Ti、Nb、Ga和REE异常富集,达到了伴生矿产的工业品位,其综合利用价值值得关注。凝灰岩自底部至顶部微量元素含量有明显增加的趋势,稀土元素(REE)在垂向上分异明显,凝灰岩上部富集轻、中稀土,向下逐渐过渡到富集重稀土类型。凝灰岩中元素的组合特征表明其原始物质可能来源于峨眉山玄武岩岩浆,属于基性火山灰成因。The geochemical features of the Late Permian tuff in Nanchuan District, Chongqing, southwestern China, were studied using the methods of inductively coupled plasma mass spectrometry （ICP-MS）, X-ray fluorescence（XRF）, powder X-ray diffraction （XRD）, A scanning electron microscope equipped with an energy dispersive X-ray spectrometer（SEM-EDX）. The results show that elements including A1, Ti, Li, Cu, V, Cr, Co, Ni, Nb, Ta, Zr, Hf, Ga, Sc, Th, U and REE are enriched, especially the concentrations of Ti, Nb, Ga and REE, which are higher than cut-off grades of national standards of China, respectively. The potential comprehensive utilization of Ti, Nb, Ga and REE should be paid more attention. The concentrations of trace elements increase from the bottom of tuff to the top, and the rare earth elements （REE） in tuff have obviously differentiation, the upper portion of tuff enriched light rare earth elements （LREE） and medium rare earth elements （ MREE ）, while the lower portion enriched heavy rare earth elements （HREE）. The characteristics of elements and its assemblage in the tuff show that the materials of tuff may be originated from Emeishan basalt magma and of the mafic volcanic origin.

关 键 词：凝灰岩 稀土元素 地球化学 重庆南川 

分 类 号：P595[天文地球—地球化学]