磁铁矿广泛出现于各种类型的岩石中,具有反尖晶石结构.Si与Fe无论是从离子半径还是从电子的获取能力上均存在较大区别,然而无论是利用电子探针分析还是湿化学法,很多研究均表明:磁铁矿晶体中含有一定数量的硅.‘目前,硅是否类似于Al、Mg、Ti等元素,以类质同象的方式进入磁铁矿晶格目前尚不明确.已有研究表明Si在磁铁矿中的含量对磁铁矿的生成环境(成矿环境)有较大的指示意义:热液环境中生成的磁铁矿晶体的SiO2的含量可达6.19 wt％,而在一些正岩浆型的磁铁矿中,SiO2的含量常常低于电子探针的检出限.结合实际研究资料,尝试阐明新疆哈密地区雅满苏矽卡岩型矿床磁铁矿晶体中硅的可能赋存状态.研究表明,新疆雅满苏矽卡岩型磁铁矿矿床中的磁铁矿中SiO2的含量相对较高,而且Si的含量与Fe3+含量呈明显的线性负相关关系;穆斯堡尔谱结果亦指示Si替换了四面体上Fe3+的位置,并且在八面体位置上四极分裂愈大,类质同象替代愈加广泛.%Magnetite,which has an inverse spinel structure,occurs widely from hydrothermal to magmatic rocks.As has been known for long time,it carries some foreign elements such as Al and Ti,even silicon.Silicon and iron are quite different,either from the ionic radii or electron-obtaining ability.However,both electron microprobe data and wet chemical methods analyses show that magnetite contains certain amount of silicon.Whether the silicon is similar to Al,Mg and Ti,entering into the magnetite lattice,is not clear.Studies have shown that silicon content in magnetite may be related to diagenetic environment.In the hydrothermal environment,silicon content may be up to 6.19 wt％;whereas in magmatic ones,it seems that silicon content is mostly under detection limit.The aim of this study is to identify the status of silicon in magnetite and decipher the relations between silicon content and diagenetic environments.Study on the Yamansu skarn-type magnetite shows that (1) silicon content in magnetite from Yanmansu skarn-type deposit is relatively high and the contents of Si and Fe3 + have obvious negative linear relationship;(2) M(o)ssbauer spectrum results also indicate that Si replaces the position of Fe3+ in the tetrahedron and the more quadruple splitting in the octahedral,the more widely isomorphous substitution.
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