W and V mineralization in Langban-type Fe-Mn deposits: Epigenetic or syngenetic?

New observations of minerals rich in W and V at the carbonate-hosted Langban-type Fe-Mn-(Ba-As-Pb-Sb) deposits in the Bergslagen region, Sweden, have been made. Scheelite with variable but high Mo contents (up to 40 mol.% powellite) commonly occurs in the hematite-quartz ores. Crystals of welinite, found in vein assemblages (Langban, Sjogruvan) and in Mn skarn matrices (Sjogruvan) , are often complexly zoned and display some solid solution towards the Sb-Fe counter-part orebroite. Manganberzeliite containing up to 20 mol.% of its vanadate analogue (palenzonaite) in solid solution has been recorded from the Jakobsberg deposit. In contrast to previous assumptions, there appears to be no genetic link between local granitic rocks and the W minerals. W, as well as V, is inferred to be syngenetic with Fe and Mn at these deposits.