摘要
广西东部一些具“Ⅰ”型特征的燕山期花岗岩体中富含微粒包体,而微粒包体在主岩中含量一般为1～5％,其粒度小、色率高、酸度低,一般长轴数厘米至数十厘米,与主岩界线清楚。本文通过对微粒包体的岩石学特征、稀土与稀有元素特征与主岩对比,二者具有较多共同之处,证明它们之间有亲缘演化关系。认为绝大部分微粒包体应来自主岩同源岩浆的先期侵入岩,它们在岩石特征和成因上都与该地区海西—印支期陆壳转生型花岗岩中的包体明显不同,包体成为两类不同成因花岗岩的重要标志之一。
Some Yanshanian I-type granite bodies in east Guangxi are rich in micrograined inclusions. The amount of these inclusions in host rocks are generally 1 to 5 per cent. They are characterized by small grain,high colour index,low acidity,several to several ten centimeters of major axis in length and the clear boundary with the host rocks. Through comparison between the micrograined inclusion and the host rock in the aspects of lithochemistry ,rare earth elements and rare elements in this paper, it is proved that they (inclusion and host rock) have many things in common and related evoluational relation. It is believed that most micrograined inclusions should come from the earlier intrusive rocks of related magma with the host rocks. But these inclusions are obviously different from those in Her-cynian-Indosinian continental crustal transformation -type granites in lithological characteritics and genesis. So inclusion is one of important marks for identifying these two kinds of different genetic granites.
