Ti-Fe-Cr spinels in layered (stratified) complexes of the western slope of the Southern Urals: species diversity and formation conditions

Abstract

Materials on geochemistry and ore Fe-Ti-Cr mineralization of rocks composing layered (stratified) bodies of the western slope of the Southern Urals are presented. A detailed analysis showed similarity in the redistribution of REE, noble metals, and Fe-Ti-Cr mineralization of practically all parameters in rocks of the Misaelga and Kusin-Kopan complexes. It has been established that the parameters of metamorphism, which influenced components redistribution in Fe-Ti-Cr minerals of the layered complexes, correspond to Misaelga – T = <550-750 °С, P = 0.1-2.8 kbar, Kusin-Kopan – T = <550-630 °С, P = 0.3-0.7 kbar, and Shuidinsky complexes – T = <550-760 °С, P = 0.5-2.5 kbar. The result of modelling the melt crystallization process showed that the Kusin-Kopan complex is an intrusive body with an ultramafic horizon in the idealized cross-section. Due to collisional processes, the lower part of the intrusion has been detached from the upper part. The proposed structure of the Kusin-Kopan complex sharply increases its prospects for such types of minerals as platinum group minerals + sulphide copper-nickel mine-ralization and/or chromites.