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International Geology Review, vol.68, no.2, pp.109-136, 2026 (SCI-Expanded, Scopus)
In this study, we focus on the Cenozoic magmatic suites in the Lut Block, a segment of the EIMB. The investigated plutonic rocks in the Lut Block, ranging in age from 47 to 37 Ma, encompass a wide compositional range from mafic to felsic, displaying medium to high-K calc-alkaline affinities. Epsilon Nd values in the investigated rocks range between −2.8 and +2.8, and the initial Sr isotope ratios is constrained to 0.7045‒0.7065. The age-corrected Pb isotopic compositions display ratios of2 0 6 Pb/2 0 4 Pb between 18.01 and 18.46, 2 0 7 Pb/2 0 4 Pb from 15.49 to 15.57, and2 0 8 Pb/2 0 4 Pb ranging from 38.19 to 38.47. Isotopic–incompatible trace elements modelling reveals the contribution of up to 2.5% sediment-derived melt and approximately 7% to as little as 2% assimilation of continental crust. A broader perspective on the Lut Block geochronological–isotopic data reveals a transitional shift in magmatism from the eastern (e.g. Bajestan; ~ 82 Ma) to the western (e.g. NW Gonabad, Gazu, Kajeh, and Vaghi; ~80 Ma to ~60 Ma) segments, peaking in magmatism during ~45 to ~38 Ma. This shift in magmatism may be associated with a change in the subduction mechanism of the Neo-Tethyan slab beneath Central Iran, transitioning from a low-angle dip to a higher dip following slab roll-back and the tilting of the lithospheric mantle along Eastern Iran. We hypothesize partial melting of phlogopite-bearing mantle sources metasomatized by sediment melts within the pre-collisional tectonic context, contributing to the widespread Eocene high-K magmatism throughout the Lut Block.