Geochronological and isotopic data from the adakitic Dodurga Pluton (Central Pontides, N Turkiye): new insights for the geodynamic evolution of the northern Neotethys

İngilizce (OpenAlex)

The Dodurga Pluton is located within the Central Pontides (northern Türkiye) and, has a SW-NE elongation, and consists of granodiorite and dacite porphyry. Previous studies have suggested that this pluton is Triassic in age, and its whole-rock geochemical systematics are consistent with those from adakitic magmatic occurrences rather than the classic arc granitoid suite. This study reports the first time in-situ/whole-rock radiogenic isotopic (Sr, Nd and Pb) and mica/amphibole Ar-Ar age data to evaluate better its petrogenetic-geodynamic evolution and chemical nature of mantle source(s). Unlike previous data, combined new in-situ zircon U-Pb yield Late Cretaceous crystallization ages of 84.2±0.9 Ma and 86.9±0.9 Ma, and Ar-Ar age data along with apatite fission track measurements suggest magma cooling extending to 82.3±0.4 Ma and 85.4±0.4 Ma, respectively. The apatite fission track (AFT) dating results also reveal that this pluton was buried at a depth of 2.5-3 km following a fast-cooling period during Late Cretaceous and cooled/exhumed over ~2 km during the Middle-Late Miocene (15-10 Ma) in a slow cooling phase. The overall data reported here suggest that the Dodurga Pluton represents melts derived from an enriched/metasomatized mantle source that interacted with lower crustal mafic rocks in an active continental margin as a result of northward subduction of the northern branch of the Neotethys Ocean.