Comparative Nd-Sr-Pb isotopes geochemistry of the eastern Circum-Rhodope belt ophiolitic mafic suites, Greece-Bulgaria

Abstract

We report on the isotopic compositions of the Jurassic supra-subduction zone Evros ophiolite mafic rocks exposed in the eastern Circum-Rhodope Belt in the Thrace region of northeastern Greece. These mafic units consist of low-Ti gabbroic and basaltic rocks, which Nd-Sr-Pb isotopes are compatible with dominant mantle-derived Mid-Ocean Ridge Basalt (MORB) component mixed with a detectable amount of crustal material and/or sediment involved in their melt source in the subduction zone. These isotopic features are consistent with an intra-oceanic arc origin of the mafic ophiolite rocks, and the Evros ophiolite Nd and Pb isotopes are comparable to those of the counterpart mafic rocks from the Mandritsa Unit in the eastern Rhodope Massif of southern Bulgaria.