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- MakaleYalnız künye2025Mantle genesis and crustal contamination in Carboniferous granitoids using U-Th-K concentrations at the Akşar Pluton in the Eastern Pontides, NE Türkiye
Maden, Nafız; Gücer, Mehmet Ali; Akaryalı, Enver
New radiogenic heat production (RHP) data are presented for Carboniferous granites outcropping in the Akşar region (Bayburt, NE Turkey) to contribute to ongoing debates on the genetic and lithologic relationship between the Akşar and Gümüşhane plutons, which is the most widely distributed granitic rocks in the region. The scope of this study consists of rocks composed of enriched mantle material metasomatized by fluids from the previously subducted plate. We observed average K value for the Akşar Pluton was found to be 3.09 ± 1.58 %. Additionally, average Th/U and U/Th values of 3.95 ± 1.37 and 0.29 ± 0.10, respectively. The calculated RHP value for the Akşar Pluton was 2.20 ± 0.56 μWm−3. Numerical results suggest that the Carboniferous Akşar pluton's primary magma was the product of mixing lithospheric mantle and mid-to-lower crustal melts because of partial melting, differentiation, and emplacement in the shallow continental magma chamber. The geochemical and petrogenetic characteristics of the Akşar region magmas suggest that crustal contamination occurred at multiple levels, particularly within the lower to middle crust of the plutonic core complex. This complex likely retains geochemical signatures indicative of subducted Paleotethys oceanic lithosphere. These findings provide critical insights into the magmatic evolution of the Eastern Pontides, contributing to a more comprehensive understanding of crust–mantle interactions and the broader geodynamic framework of northeastern Türkiye.
- MakaleAçık Erişim2024Geochemical and petrological features of Carboniferous granites from the Güneydere (Bayburt) area
Gücer, Mehmet Ali; Delimehmet, Zeynep; Çimen, Okay
Middle-Late Carboniferousgranitic rocks are widely observed in larger outcrops in the Eastern Pontide orogenic belt of the Eastern Sakarya Zone. This tectonic belt is an important part of the Anatolian plate in terms of containing igneous rocks with a wide age and composition range. This study presents new petrochemical-petrological data on Carboniferous granites in the G & uuml;neydere and surrounding area of Bayburt (NE Turkey). The granitic rocks, which include an area of approximately 5 km, represent the pre-Jurassic basement in the study area. Besides, they are unconformably overlain by Early- Middle Jurassic volcano-clastics units and Late Jurassic- Early Cretaceous limestones. They mainly consist ofgranite, granite porphyry and aplite, to a lesser extent granodiorite and quartz monzonite. Rocks have high SiO2 contents (60.43-75.51%) and high K calc-alkali to shoshonitic affinities and have been derived from an I-type source. The granitic rocks are metalumine-peralumine in character and are similar to postcollisional volcanic arc granitoids. Whole-rocks major and trace element trends show that plagioclase, hornblende, biotite, apatite, and Fe-Ti oxide mineral fractionations play an important role in the formation of the rocks. It has been revealed that fractional crystallization and assimilation+magma mixing processes play a role in the development of granites. Also, the saturation temperatures calculated from the whole-rock zircon values reflect lower initial magma temperatures. All results obtained indicate that parental magma of studied granitic rocks have evolved from lower/middle crust- derived melts as a result of partial melting and differentiated and emplaced in the continental magma chamber.