Chromite compositional variability and associated PGE enrichments in chromitites from the Gomati and Nea Roda ophiolite, Chalkidiki, Northern Greece

Abstract The Gomati and Nea Roda ophiolites are located into the Serbo-Macedonian massif of Chalkidiki peninsula (Northern Greece). present work focuses on variability platinum-group elements (PGEs), geochemistry, spinel mineral chemistry, minerals (PGMs) — base metal (BMMs) assemblage in chromitites three localities (St. George, Tripes, Limonadika) Roda. studied show variable textures heavily altered. Primary silicates almost completely replaced by chlorite, chromite rims altered ferrian chromite. chemistry terms Cr# [Cr/(Cr + Al)] Mg# [Mg/(Mg Fe 2+ )], PGE contents, argues for a genesis supra-subduction setting (SSZ), at different stratigraphic positions ophiolite section. Chromitites from Tripes have lowest (0.5–0.6) highest contents (3516 ppb), similar to some formed small magma chambers cumulate sections above Moho. high due an IPGEs-enriched melt derived critical melting mantle peridotites. Limonadika St. George (0.77–0.96 0.74–0.87, respectively) (175 ppb 383 average respectively), compatible with boninitic magmas intermediate (0.66–0.75) low (135 average) similarities other evolving sources subduction initiation. BMMs detected both primary (pentlandite) secondary (mainly millerite heazlewoodite) sulfides. All PGMs primary, crystallized melt, entrapped chromite, they mainly laurites. In chromitites, absence alloys indicates that circulating fluids during chloritization were fS 2 fO , did not remobilize PGEs. same probably responsible low-T crystallization uncommon suite arsenides antimonides George.