Early Paleozoic metabasalts and metasedimentary rocks from the Male Karpaty Mts (Western Carpathians): Evidence for rift basin and ancient oceanic crust

Most of the Maid Karpaty Mts, which form a geographical connecting link bet ween the Eastern Alps and Western Carpathians, consists of an Early Paleozo ic low-grade metamorphic complex intruded by Lower Carboniferous granitoid plutons. Metamorphic recrystallization connected with granite emplacement l ed to the formation of a crystalline complex metamorphosed under greenschis t to amphibolite facies conditions. Major and trace element contents: of me tabasalts and elastic metasedimentary rocks have been studied in this cryst alline complex. Distribution of relatively immobile trace elements (REE, HF SE) was unaffected by metamorphism and reflects original magmatic or sedime ntary compositions. Two geochemical types of metabasalts have been indentif ied in relation to their geological position: (1) metabasalts occurring in association with metagabbros, metadolerites and small amounts of black shal es and metacherts are of N-MORB type and (2) small metabasalt bodies in ela stic metasedimentary rocks with sporadic carbonates are close to E-MORB/OIT or CT in composition. The elastic sedimentary rocks are represented by alt ernating metapsammitic rocks with Variable admixture of pelitic component a nd organic matter together with a smaller amount of metapelitic rocks and b lack shales. Relatively uniform major and trace element distribution in the elastic metasedimentary rocks indicates uniformity of the composition and source area of protolith. The protolith of the metasedimentary rocks were d ose to greywackes from the ensialic back-are basin depositional setting, wi th a source comprising mostly a mixture of acid and intermediate magmatic r ocks in the upper continental crust. A new lithostratigraphical division of the Early Paleozoic complex of tilt: Male Karpaty Mts is proposed. We defi ne here two groups: (1) the Pernek Group - a metamorphosed incomplete: (dis membered) ophiolite sequence representing a relic of the upper part of the oceanic crust Pre Lower Carboniferous in age and (2) the Pezinok Group comp osed of elastic metasedimentary rocks with a small amount of metacarbonates and metabasalts with E-MORB/OIT or CT signature Silurian-Devonian in age w hich represents a part of the rift basin fill probably inboard of an ensial ic island are. Both groups came into contact during strong shortening and n appe formation processes in the Pre-Early Carboniferous (Late Devonian?) ti me.