Composition and textures of the minerals of FeO-Fe2O3-TiO2 system in volcanic rocks and porphyry copper deposits of the Bor metallogenic zone

Proces obrazovanja minerala iz sistema FeO-Fe2O3-TiO2 u uzorcima vulkanskih stena i porfirskih orudnjenja borske zone prikazan kroz pojavu magnetita/hematita i njihovih alteracija. Minerali ove zone su ispitivani optičkim metodama (odbijena i propuštena svetlost), SEM-EDS/BSD, XRPD, LA-ICP-MS metodama. Rezultati ispitivanja su, pored glavnih Fe – Ti oksida, otkrili prisustvo ferijskog ilmenita u hornblenda andezitima I vulkanske faze kao i magnetita sa većim koncetracija Cr u zoni zlotske magnetne anomalije. Ispitivanje uzoraka iz bušotina porfirskih sistema borske zone otkriva postojanje nekoliko tipova (obrazovanog pod hidrotermalnim uslovima) magnetita/hematita vezanih za različite zone alteracije. Magnetit su u ovim sistemima javlja kao tip I u paragenezi sa bornitom i halkopiritom, tip IIa nastao u paragenezi sa piritom i halkopiritom i kao tip IIb nastao u istoj paragenezi ali kao produkt alteracije hematita (varijetet mušketovit). Hematit takođe pokazuje, slično kao magnetit, nekoliko tipova. Tip I hematit je vezan za paragenezu bornit – halkopirit i nastaje kao produkt alteracije magnetita. Tip IIa hematit je primarno obrazovan hematit u okviru parageneze pirit – halkopirit nastao precipitacijom iz hidrotermalnog rastvora dok je tip IIb nastao alteracijom magnetita. Svi navedeni tipovi su prikazani kroz teksture i sastav mikro i elemenata u tragovima.The process of formation of mineral system FeO-Fe2O3-TiO2 in samples from volcanic rocks and porphyry deposits of Bor zone is explained through occurrences of magnetite/hematite and their alterations. Minerals of this zone is examined by optical (transmited and reflected light), SEM-EDS/BSD, XRPD, LA-ICP-MS methods. Results of examination reveals, beside main Fe-Ti oxides, presence of ferrian ilmenite in hornblende andesites of I volcanic phase as well as magnetite with notable Cr concentration in zone of Zlot magnetic anomaly. Examination of samples from porphyry system drill holes of Bor zone reveals different types of (under hydrothermal condition) magnetite/hematite in different porphyry alteration zone. Magnetite of this system is presented as type I in paragenesis with bornite i chalcopyrite, type IIa with pyrite and chalcopyrite and type IIb as alteration product of hematite (mushketovite). Hematite also show, similar to magnetit, different types. Type I hematite is in paragenetic relationship with bornite and chalcopyrite as alteration product of magnetite. Type IIa is primary formed hematite in pyrite-chalcopyrite paragenesis through process of precipitacion from solution and type IIb is alteration product of magnetite in same paragenesis. All types are presented through mineral textures and composition of micro and trace elements