粤东一些铁矿床中磁铁矿的标型特征及其成因意义

Typomorphic Characteristics and Genesis Significance of Magnetite from some Iron Ore Deposits in Eastern Guangdong

磁铁矿是许多类型铁矿床中的一种主要工业矿物。因为形成的物理化学条件各异,它们的物理性质和化学性质,以及它们的矿物共生组合必然会有所差别。本文以粤东一些主要铁矿床中磁铁矿研究为例,论述它们的标型特征和其成因意义。一、磁铁矿的产状粤东铁矿成因类型比较齐全,主要有霞岚晚期岩浆分异矿床。

This article deals with the occurrence,mineral assemblages,physical and chemical properties of magnetite in eastern Guangdong.The study shows that different occurrences and assemblages of magnetite correspond to different geneses.Mineralogical evidences suggest that the physical properties of magnetite are related with the FeO,MgO,MnO contents,i.e.,along with the increase of the contents of these constituents there are decreases of gravity(5.17→4.79),indentation hardness(725→551Kg/mm^(2))and increase in unit cell constants(8.392→8.477 A)of the magnetites.The variations of those properties of magnetite are closely connected with their geneses.In paragenesis of minor elements of magnetite,there are high percentages of Ti,Cr,Ni,Co and V,Ti:V=10:1,Co:Ni=1:1 in magnetite from post-magmatic differentiation iron deposits;high percentages of Mn,Mg,Zn and Sn,Ti:V=50:1,Co:Ni=2:1-3:1 in magnetite from contact-metasomatic iron deposits;high in Ge content,Ti:V=20:1,Co:Ni=3:1 in magnetite of volcano-sedimentary iron deposits;and great amount of Mn,Mg,Sn and Ge,Ti:V=26:1,Co:Ni=1:6 in magnetite from metamorphic iron deposits.Typochemical characteristic of magnetite of different geneses are quite clear.