梅山铁矿矿石类型及成因——高温实验结果探讨

根据宁芜地区梅山铁矿的地质条件为背景而设计的方铁矿（Wü）-磷灰石（Ap）透辉石（Di）-霞石（Ne）四元系,经1400℃的高温实验,产生了液态不混溶产物——铁浆相和硅酸盐浆相。经电子探针成分分析发现,铁浆相中除主要成分为FeO外,还含有一定数量的硅酸盐、磷酸盐等成分,这些成分含量的多少,是液态不混溶作用发育程度不同的结果。通过可能形成梅山铁矿3种主要矿石类型的平衡反应式,计算了从400℃至1400℃时的lgfo2值和lgkT值,并得出梅山铁矿矿浆成矿的结论。

IRON ORE TYPES AND GENESIS OF MEISHAN IRON ORE DEPOSIT-THE STUDY OF HIGH TEMPERATURE EXPERIMENTS

Meishan iron ore deposit is situated at the suburb of Nanjing. Here a block of magnetite is seen intruding between a subvolcanic andesite and a pyroxene amphibole porphyrite. They are cretaceous in age. The contact between the iron ore and the igneous rocks is mainly sharp and clear, without graduaton. The main mineral association of the ore is apatite-diopside-magnetite and the igneous rocks are more or less alkaline. According to the geological conditions of Meishan iron ore deposite, experiments on the quaternary system of apatite-diopside-nepheline-wustite at 1400 been designed, and areas of two immiscible liquids ( an iron-rich liquid and a silicate-rich liquid) are found in this system. EPA indicate that there are FeO, silicate compoitions and in this iron- rich liquid. By the equilibrum reaction formulas which possibly indicate three main iron ore types of Meishan iron ore deposite, the values of lgPO2 and \gKT have been calculated at 400t -1400C . The fact that the main ore types of Meishan iron ore deposit can be produced by ore magma, i.e. Meishan iron ore deposit is the possible product of ore magma.