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对广西大厂矿田的侵入岩体开展主量元素、微量元素以及稀土元素的分析。结果表明,岩石中斑晶和基质主要由石英、钾长石以及斜长石组成,其中,斑晶约占15%,基质约占85%。岩石中硅含量偏低,Al2O3含量偏高;另外,Ca、Fe2O3、Na以及TiO2等含量也较低。侵入岩体中碱含量中等,属于富钾型岩石;稀土元素含量中等至偏低,其中,轻稀土元素和重稀土元素高度分馏,显示出Ce微弱负异常、Eu负异常特征。岩体富集轻稀土元素,Rb、Sr以及U等大离子亲石元素也较富集,而Nb、Th等高场强元素则相对亏损。稀土元素球粒陨石标准化分布型式总体表现出较好的一致性,大体上表明各岩体具有相似的特点、来源以及演化等,侵入岩体主要形成于碰撞时期以及板内构造时期。
Analysis of major elements, trace elements and rare earth elements in intrusive rock mass of Dachang orefield in Guangxi Province. The results show that the phenocrysts and matrices mainly consist of quartz, potash feldspar and plagioclase, of which about 15% of the plaques and 85% of the matrix are found. Low silicon content in the rock, high Al2O3 content; In addition, Ca, Fe2O3, Na and TiO2 content is also lower. The intrusive rocks are medium-alkali and belong to potassium-rich rocks. The content of REE is moderate to low, in which the light rare earth elements and heavy rare earth elements are highly fractionated, showing weak negative Ce and negative Eu anomalies. The rock mass is enriched in LREE, Rb, Sr and U are also enriched in large ion lithophile, while the elements of high field strength such as Nb and Th are relatively depleted. The normalized distribution patterns of REE chondrites generally show a good consistency, generally indicating that the rock mass has similar characteristics, sources and evolution, and intruded rock mainly formed during the collision and in-plate tectonic period.