Geochemical and Geochronological approaches of Baskil Dikes (Elazığ, Eastern Turkey): Discrimination between the Late Cretaceous Continental and Oceanic Arc-related Magmatism in the Southern Neotethys

The Southeast Anatolian Suture Belt hosts the oceanic and continental remnants of the southern Neotethyan realm. During the Late Cretaceous, the southern Neotethyan domain experienced an Andean-type magmatism on its northern continental margin (the Tauride-Anatolide Platform), characterized by the Baskil Magmatics. The plutonic part of this unit is intruded by numerous dikes, which are the primary focus of this study. The U-Pb zircon dating of the dikes and their granodioritic host rocks indicates that their emplacement occurred within a narrow interval, between 81-79 Ma. The dikes vary chemically from basalt to dacite, while the host rocks range from andesitic to dacitic. On the normal mid-ocean ridge (N-MORB)-normalized plots, all samples exhibit negative Nb anomalies. Trace element systematics reveals that this dike system is chemically heterogeneous, consisting of five distinct chemical types. The elemental and isotope ratios indicate varying contributions from depleted and enriched components. All chemical types, with relative Nb depletion, suggest incorporation of slab-derived and/or crustal additions. This interpretation is further supported by the EM-2-like Pb isotopic ratios. Based on the variability in elemental and isotopic composition, this intrusive system appears highly heterogeneous, likely due to the combined effects of mantle source, crustal contamination, and fractional crystallization. The bulk geochemical characteristics of the studied dikes and their host rocks suggest that these intrusives formed at a continental arc. Considering the available paleontological and geochronological age data, it appears that the intraoceanic subduction and continental arc magmatism in the Southern Neotethys occurred simultaneously; the former created the Yüksekova arc-basin system, whereas the latter formed the Baskil Arc.

Note: This study was supported by project Fübap-MF.15.12.