钛铁矿的穆斯鲍尔谱测试及成因信息探讨

MSSBAUER SPECTROSCOPY AND GENETIC INFORMATIONS OF ILMENITES

本文对我国攀西地区的三组钛铁矿和钛磁铁矿,进行了矿物结构,成分及穆斯鲍尔谱测试。使用穆斯鲍尔谱技术,初步区分了铁钛氧化物中铁的不同物相。分析了钛以两种方式赋存于钛磁铁矿中。使用共存铁钛氧化物成分与平衡温度和氧逸度关系图时,对Fe^(3+)和杂质元素进行了校正,求得该区钛铁矿岩浆结晶分离作用最后阶段的温度约为550—700℃,氧逸度为—lgfO_2=18～23.0。

The composition identification and Mossbauer spectroscopy analysis have been done on several ilmenite of a mining area in Southern China. For comparision with them, co-existed titanomagnetite's compositions and Mossbauer spectroscopy also have been carried out. The results show that titanium exists in two forms in magnetites: 1) exsolaved lamellar containing titanium, such as ilmenite and ulvospinel lamellar; 2) Ti^(4+) joinig into crystal lattice of magnetites and substituting Fe. The iron may exist in ilmenites in forms of Fe^(2+) or Fe^(3+). Both being detected by Mossbauer spectroscopy are calculated as end-member moleculars with detected Fe^(2+) and Fe^(3+). Using the figures of compositions and temperatures of co-existed ilmenite-hematite and magnetitculvospinel, we calculate and get the following results. The temperatures in the late stage of crystalization and segregation of magma are about550-700℃, and oxygen fugacities are about -1gfO_2 =18—23.0.