摘要
来利山锡矿床与小龙河锡矿床是滇西地区典型的云英岩型锡矿床。为揭示它们在成因上深层次的差异性,对来利山锡矿和小龙河锡矿的锡石进行了电子探针成分分析、镜下观察以及成矿环境对比分析。结果表明,锡石中的铁多以Fe^(3+)的形式与Sn^(4+)发生类质同象,氧逸度越高,锡石中Fe^(3+)越多,宏观上表现为锡石的颜色越深。来利山矿区锡石中Fe含量明显低于小龙河矿区,且锡石颜色明显比小龙河矿区颜色浅,反映了来利山锡矿成矿环境相对开放,成矿流体氧逸度偏低,流体中Sn络合物迁移能力较强,在花岗岩体外接触带的围岩裂隙中形成外云英岩型锡矿床;而小龙河锡矿成矿环境相对封闭,成矿流体氧逸度偏高,流体中Sn络合物迁移能力较弱,多在花岗岩体顶部的构造裂隙中形成内云英岩型锡矿床。
Lailishan and Xiaolonghe Sn deposits are typical greisen type Sn deposits in the west Yunnan province. Electronic probe analysis and microscope observation of ore from the two deposits are carried out and comparison analysis of metallogenic environments conducted to reveal their genetic differences. The result shows that Fe^3＋ and Sn^4＋ in cassiterite occur in isomorph and the higher the fuigacity the more Fe^3＋ occurs in the cassiterite and the deepr color the cassiterite is. Fe content in Lailishan Sn deposit is obviously lower than that in Xiaolonghe Sn deposit and color of the former＇s cassiterite is lighter than that in the latter＇s. This indicats that environment of the fomer is more open with relative low oxygen fugacity and stronger mobilizatioin of Sn complexes in the ore fluiid and the greisen type Sn deposit is formed at outer contact zone of granitic body and in fissures within wallrock and that environment of the latter is more closed with relative high oxygen fugacity and weaker mobilizatioin of Sn complexes in the ore fluiid and the greisen type Sn deposit is formed in tectonic fractures at top of granitic body.
出处
《地质找矿论丛》
CAS
CSCD
2015年第3期321-330,共10页
Contributions to Geology and Mineral Resources Research
基金
国土资源部公益性行业科研专项经费项目(编号:201211022)
中国地质调查局项目(编号:1212011085466)资助
关键词
来利山锡矿
小龙河锡矿
云英岩型锡矿床
成矿流体
氧逸度
滇西地区
Lailishan Sn deposit
Xiaolonghe Sn deposit
greisen type Sn deposit
ore fluid
oxygen fu- gacity
the west Yunnan province
