Tectonomagmatic Constraints on the Sources of Eastern Mediterranean K-rich Lavas

Abstract

Potassium-enriched mafic lavas, and in particular basalts of the high-K series, are important end-members of subduction zone volcan-ism. Two petrogenetic models can explain the generation of mafic K-rich lavas, involving either melting of ancient, enriched lithospheric mantle sources (single-stage model) or melting triggered by recent refertilization by subduction-related components derived from sub-ducted sediments or oceanic crust (multi-stage model). These two models are tested for post-collisional high-K rocks of Eocene^ Oligocene age from the Rhodopes, SE Bulgaria, based on new major element, trace element and Sr^Nd^Hf^Pb isotope data. The single-stage model is evaluated by Sr^Nd isotope modelling assuming the presence of ancient enriched lithospheric domains whereas the multi-stage model is assessed by comparing the compositions of the Bulgarian lavas with those of lavas from Santorini. Santorini lavas are considered to sample the current trace element and isotope inven-