ХЁГБОМИТ ИЗ ИЛЬМЕНИТ-МАГНЕТИТОВЫХ РУД КУСИНСКОГО МАССИВА (ЮЖНЫЙ УРАЛ)

Abstract

Hogbomite is a widespread mineral in ilmenite-magnetite ores of Kusinsky layered gabbro massif. Investi-gation of its chemical compositions has revealed two different types of hogbomites, depending on position of ore bodies in the massif cross-section. Högbomite of the 1st type, associating with spinel-bearing ores, is the lower ferrous, as compared to the 2nd type: Fe/(Fe + Mg) = 46-55 vs. 68-80, respectively. It contains also more of TiO2 (7.27 vs. 5.87 wt%) and Cr2O3 (2.26 vs. 1.94 wt%), but the lower content of Zn (1.0 vs. 2.87 wt%). Rela-tionships of högbomite with ilmenite, magnetite and chlorite show that its crystallization took place after for-mation of the ore minerals but before or simultaneously with chlorite. Thus, fixed temperature interval of hogbo-mite crystallization makes from 600 to 300 °C at the pressure 7-6 kbar. Within these limits, crystallization of the 1st type högbomite was finished at 340 °C, so as the 2nd type hogbomite crystallized under about 300 °C but at the higher oxigen fugacity.