摘要
荷载微粒闪长质包体是全球范围内Ⅰ型花岗岩的普遍特征，本文对中国东部不同构造域内印支期以来的典型岩体及其荷载微粒闪长质包体进行了对比研究，提出两种岩浆并存的地质、岩石学标志。根据岩石∈Ｎｄ＿０和Ｔ＿（ＤＭ），模式年龄的大小将花岗岩及其荷载闪长质包体划分为三种组合类型：①花岗岩Ｔ＿（ＤＭ）明显大于或∈Ｎｄ＿０明显小于荷栽微粒闪长质包体；②花岗岩Ｔ＿（ＤＭ）明显小于或∈Ｎｄ＿０明显大于微粒闪长质包体；③二者相近。指出三种组合类型分别受①古老地壳区（早元古－太古宙），②较新造山带（古生代以来），③较老地壳区（中、晚元古代）所制约。提出花岗岩及其荷载微粒闪长质包体是分别来自深部地壳不同成分层部分熔融的成因观点。
ost of the I-type granitesq in world are characterized by containingmicrogranular dioritic enclaves.Through comparison study of the typical intrusion andtheir microgranular dioritic enelaves from different tectonic domain in eastern China sinceIndosinian epoch the paper proposes some geological and petrological evidences for an ideaof co-existing of two kind magmas,According to the variations of ∈Nd and T_(KM)modeIages,the granites and their dioritic enclaves are classified into three association types:i.e.(l)the granites with their T_(DM)obviously larger than that of the microgranular dioriticenclaves;(2)the granites with their _(DM)strikingly smaIler or ∈Nd strikingly larger thanthat of microgranular dioritic enclaves;(3)granites with their character values similar tothat of the enclaves. These three types of granites and enclaves are controlled respectivelyby old crustal region(Early Proterozoic-Archean),newer orogenic belt(SincePaleozoic)and older crustal region(Late Proterozoic).So it is suggested that granitesand their microgranular dioritic enclaves are derived respectively trom partial melting ofdifferent composition layers in deep crust.
基金
国家教委博士点基金
关键词
微粒闪长质包体
花岗岩
成因
Eastern China,microgranular dioritic enclave,granites
