Geochemical characteristics of Mn (± Fe) ore occurrences near Sliven and Yambol towns (eastern Bulgaria)

The study presents new field data combined with detailed mineralogical and geochemical research of the Mn- and Fe-bearing ore occurrences located in the areas of the towns of Sliven and Yambol. The two Mn (± Fe)-bearing mineralized areas are formed in a similar position at the contact between the volcanic materials and the clayey limestones of the upper Santonian Draganovo Formation. Ore minerals show varying layered-like to massive morphology or form nests, coatings and needle-like aggregates associated with quartz, calcite, and barite. More significant trace elements in the manganese oxides from the Glushnik ore occurrence are Cu, Zn, As, V, and P while the ore phases at the Izvor ore occurrence are predominantly enriched in Ba, Sr, V, Cu, and Zn.