摘要
浙江泰顺洋滨斑岩锡矿成矿母岩为黄玉花岗质斑岩脉,主要有黄玉钾长花岗斑岩(Ⅳ号脉),黄玉二长花岗斑岩(Ⅰ号脉深部)和黄英斑岩(Ⅰ号脉浅部)。组成基质的黄玉占全岩10-22％,具典型火成斑状结构。组成斑晶矿物主要有石英、条纹长石、钠长石和黑鳞云母。根据全岩高的F/Cl值(146-303),强过铝质(A/NKC=1.574～12.938)和K_2O>Na_2O等特点判断,在成因上与华南S型花岗岩相似。石英斑晶中含大量原生流体包裹体,其均一温度为180-472℃,含盐度为3.7～44.4wt％NaCl。此外还含少量不均匀包裹体,由数个结晶相(石英,云母和黄玉)和气液相组成,它是在流体/熔体不混溶作用下被捕获的。本文还从富F熔体的解聚作用。
The rocks with porphyry tin deposits in the Yangbin area are mainly topaz-bearing granitic porphyry dikes, namely topaz potash feldspar granitic porphyry (number IV dike), topaz monzogranitic porphyry (the deep part of number I dike) and topazite porphyry (the shallow, part of number I dike). The rocks usualy have typical porphyritic textures, and the topaz essentially comprises the groundmass, making up about 20％ of whole rock in volume. The phenocrysts usually consist of quartz, microcline perthite, albite and protlithionite. Juding from petrochemistries of the rock, for example, higher F/Cl values (146-303), strong peralumina (A/NKC=1.574-12.938) and K_2O>Na_2O, etc., they are similar in genesis to south China S type granites. In quartz phenocryst there are more primary fluid inclusions with homogenization temperatures of 180-472℃ and salinties of 3.7-44.4 wt％ NaCl and some inhomogeneous inclusions. The latter, having been trapped during the fluid/melt immiscible process period, consist, in part, of crystalline phases (quartz,mica and topaz) and in other parts of gas-liquid phases., In this paper the authors also discuss the petrogenetic mechanism, such as depolymerisation, immiscibility and reverse evolution of F-rich melt in order to interpret the lithologic assemblages in the area.
出处
《南京大学学报（自然科学版）》
CAS
CSCD
1993年第3期448-459,共12页
Journal of Nanjing University（Natural Science）
基金
国家自然科学基金
关键词
含锡斑岩
黄玉
矿物包体
tin-bearing porphyry
genesis of topaz
inclusions
