Geological and general geochemical characteristics of Fe-Ni oolitic ores of the Mokra gora basin (Western Serbia)

Abstract

The Mokra Gora basin (30 km²) in the Western Serbia is one of most important among numerous localities with Upper Cretaceous sedimentary iron-nickel ores appearing in central and southern parts of the Balkan Peninsula.  The ore formation makes a basal part of a thick (>900 m) Upper Cretaceous marly-limstones complex and consists of iron-rich (pertly with oolites) conglomerates, conglomeratic sandstones, sandstones, and marls, locally with chart intercalations. The ore formation transgressively covers serpenunites of the Zlatibor massif and as the basin is a pseudoanticlyne with the axis orientation 234/14, it outcrops at northem, eastern, and southern borders of the basin. It is characterized by an average thickness of 19.4 m and Fe-chlorite, hematite, magnetite. goethite, and some pyrite, marcasite, bravoite, and millerite. In a relic of lateritic weathering crust of ultramafites underlying the ore formation, hematite, talc, kotchubeite, and Ni-serpentinite appear. Average contents (in %) of Fe, Ni, Co, Cr, and SiO, are 21,7, 0.7, 0.02, and 1.22, respectively.