相山火山-侵入杂岩的反方向岩浆演化系列研究  

Reverse magmatic evolution series of the Xiangshan volcanic intrusive complex

作　　者：张万良[1] 

机构地区：[1]核工业北京地质研究院

出　　处：《中国地质》2005年第4期548-556,共9页Geology in China

基　　金：核工业地质局地质项目(200221)资助

摘　　要：相山因是中国最大火山岩型铀矿产地而倍受关注,相山火山-侵入杂岩从喷发—侵出—侵入,SiO2含量、Rb/Sr、Rb/Ba比值降低,而TFe(Fe2O3+FeO)、CaO、MgO、TiO2、P2O5含量、SI(固结指数)、δEu则呈增高趋势,岩浆演化与正常岩浆房酸度逐渐增高的岩浆分异趋势相反,称反方向岩浆演化系列。不相容元素的比值如Th/U、Rb/Ba、Th/Nb、Th/Ta、La/Nb、Nb/Ta变化幅度较大,与SiO2组分没有明显的正消长或反消长关系,稀土配分曲线也不尽一致,火山喷发相、侵出相和侵入相岩石具有不同的源区性质。The Xiangshan area as the largest volcanic-hosted uranium ore occurrence in China has received great attention. From emption→viscous lava extmsion→intmsion, the SiO2 content, Rb/Sr and Rb/Ba of the Xiangshan volcanic-intrusive complex decreased, while the TFe （Fe2O3＋FeO）, CaO, MgO, P2O5 and TiO2 contents and the solidification index SI and δEu increased progressively, showing that the magmatic evolution has an antithetic relationship with the magmatic differentiation trend reflected by increasing acidity in the normal magma chamber, which is called the reverse magmatic evolution series. The incompatible element radios such as Th/U, Rb/Ba, Th/Nb, Th/Ta, Nb/Ta and La/Nb vary widely, showing no distinct synthetic or antithetic relationship with the major components such as SiO2. The REE distribution patterns also vary. These suggest that the volcanic eruption facies, viscous lava extrusion facies and intrusive facies were derived from different sources.

关 键 词：反方向岩浆演化 岩石地球化学 源区性质 相山 

分 类 号：P588.12[天文地球—岩石学]