Akademik Veri Yönetim Sistemi
Lithos, cilt.518-519, 2025 (SCI-Expanded, Scopus)
In northwestern Türkiye, near the Türkiye-Bulgaria border, the Late Cretaceous Demirköy Intrusive Suite forms a key component of the northern Tethyan magmatic arc developed during the subduction of the Neotethyan oceanic lithosphere beneath the Eurasian margin. The Demirköy Intrusive Suite intrudes the metamorphic basement of the Strandja Crystalline Complex and consists of gabbro, diorite, quartz diorite, granodiorite, and granite. Except for the mafic units (gabbro-diorite), which are characterised by intrusive contacts with all surrounding rocks, the suite lithologies exhibit transitional field relationships, indicating a genetic linkage among the felsic units. Geochemically, the felsic rocks are subalkaline-calc-alkaline, metaluminous to peraluminous, whereas the mafic rocks occupy the tholeiitic–alkaline transition field. Trace-element and REE systematics point to a mantle-crust interaction origin with upper-crustal contributions, and isotopic compositions (εNd(t) = +0.7 to +3.1 for felsic; +1.3 to +2.4 for mafic rocks) indicate derivation from a mafic parental magma sourced from subduction-modified mantle, variably affected by fractional crystallisation and AFC–CC processes. Zircon U-Pb ages of 82.4–80.3 Ma for both mafic and felsic rocks, together with amphibole 40Ar/39Ar cooling ages of 84.0–79.5 Ma, confirm emplacement during the Santonian–Campanian interval. Textural observations and field relationships indicate that the system consists of coeval mantle-derived mafic magmas and felsic magmas produced through the mixing and hybridisation of crustal melts. These lines of evidence collectively support a model of bimodal magmatism generated from two distinct sources rather than through a single differentiation process. The DIS provides new insights into the petrogenesis of arc-related bimodal magmatism and improves our understanding of crust–mantle interaction and magma evolution along convergent continental margins worldwide.