滇西马厂箐岩体及其中深源包体地球化学特征

云南马厂箐岩体是滇西喜马拉雅期富碱侵入岩带的重要组成部分,具有高钾富碱的特征,属于高钾钙碱性或钾玄岩岩石系列。该岩体中首次发现镁铁质深源暗色包体,寄主岩及包体的对比研究为揭示富碱岩浆的性质、起源及成岩成矿的地球动力学机制提供了可靠的地质依据。包体大部分呈浑圆状或次圆状,微细粒结构,包体中含针状磷灰石,部分包体中含有寄主岩石中的钾长石和石英斑晶。包体及寄主岩的主量和微量元素协变图呈不同程度的直线变异关系,而且稀土、微量元素曲线形态相近,显示了包体和寄主岩在地球化学特征上既有相似性,又具有明显非同源性的特点。以上特征表明,马厂箐岩体中的暗色包体是壳幔岩浆混合的产物,幔源岩浆的混合注入是这套岩浆成矿的关键因素。

Geochemical Characteristics of the Machangqing Intrusive and Its Deep-Derived Enclaves,Western Yunnan Province

Mafic,deep-derived and dark-colored enclaves have been discovered for the first time in the Machangqing alkali-rich porphyry in Yunnan Province,which supply more credible geologic evidence to study and reveal the property and origin of the alkali-rich magma and to understand geodynamics of the rock and ore-formation.The enclaves are mainly round or sub-round and are featured by mircogranular-fine grained texture,including acicular apatite.Some enclaves contain K-feldspar and quartz phenocrysts from host roc...