摘要
滇西马厂箐富碱斑岩是滇西一个重要含矿斑岩体。探讨该斑岩体的岩浆属性,为找矿提供理论依据。通过对岩体岩相学研究及元素地球化学分析,结果表明该斑岩具有富碱高K、Th、La等大离子亲石元素,以及Ta、Nb和部分高场强元素亏损,轻重稀土元素强烈分异的地球化学特征;其w La/w Sm,w La/w Yb,无或极弱的δCe和δEu负异常,MgO,Hf,Th,Ta等元素均指示该岩体具有埃达克岩岩浆的亲合性,但不完全等同于典型埃达克岩。该岩体是增厚下地壳重熔形成的花岗质岩浆与幔源富碱岩浆混合作用的产物,该混合熔体的形成并伴随其结晶成岩过程的含矿地幔流体的交代蚀变是促进马厂箐富碱斑岩成矿的关键因素。
The porphyry rich in alkali of Machangqing is an important ore-bearing porphyry body.This paper discusses the magma property of the porphyry to provide the theory and basis for prospecting.The petrographical study and the geochemical analysis of elements show that the porphyry has the following geochemical characteristics.The contents of K,Th,La and some large ion lithophile elements are high,the contents of Ta,Nb and some high field-strength elements are deficit,LREE and HREE have strong differentiation.There is not the value of La/Sm and La/Yb,or very weak negative anomaly of Ce and Eu,MgO,Hf,Th,Ta and other major or trace elements.All these indicate that the porphyry rich in alkali is similar to adakite,but not completely equal to the typical adakite.The porphyry rich in alkali of Machangqing is an felsic mixing melt of the granitic magma from the thickening lower crust partial melting and the magma rich in alkali from mantle.The metasomatic alteration of the ore-bearing mantle fluid accompany with the mixing melt in the process of crystallization and diagenesis is the key factor in the porphyry rich in alkali mineralization of Machangqing.
出处
《成都理工大学学报（自然科学版）》
CAS
CSCD
北大核心
2014年第2期217-226,共10页
Journal of Chengdu University of Technology: Science & Technology Edition
基金
国家自然科学基金资助项目(40773031)
教育部博士学科点基金资助项目(20115122110005)
成都理工大学矿物学岩石学矿床学国家重点(培育)学科建设基金资助项目(SZD0407)
