Akademik Veri Yönetim Sistemi
Yerbilimleri/ Earth Sciences, cilt.47, sa.1, ss.92-109, 2026 (Scopus)
The isotropic gabbros exposed within the ophiolitic units south of Lake Van (Gevaş) provide important constraints on the Late Cretaceous evolution of the southern branch of the Neo-Tethys Ocean. In this study, major oxide, trace element and rare earth element (REE) analyses of the gabbroic rocks were carried out and evaluated within a regional geodynamic framework. The gabbros display subalkaline affinities, characterized by low–moderate TiO2 contents, pronounced Nb–Ta negative anomalies and enrichment in large ion lithophile elements (LILE; Ba, Sr) on N-MORB-normalized multi-element diagrams. Their REE patterns generally show slight LREE enrichment or nearly flat distributions without significant HREE depletion, suggesting partial melting within the spinel-peridotite stability field. These geochemical features indicate derivation from a depleted mantle source that was metasomatized by subduction-related fluids, followed by moderate degrees of partial melting. Systematic trends observed in major and trace element variation diagrams point to fractional crystallization processes involving olivine ± clinopyroxene ± plagioclase during magma evolution. The geochemical characteristics of the Gevaş gabbros are consistent with those reported from the northern belt ophiolites of southeastern Anatolia and the suprasubduction zone (SSZ) ophiolites of the Zagros belt in Iran. These results suggest that the isotropic gabbros represent plutonic equivalents of SSZ-related magmatism developed during the closure of the southern Neo-Tethys and record the regional continuity of subduction-controlled oceanic crust formation along the Bitlis–Zagros Suture Zone.