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

The Dodurga Pluton is located within the Central Pontides (northern Türkiye), 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 is consistent with that from adakitic magmatic occurrences rather than the classic arc granitoid suite. This study reports for 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 the 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 the 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 the 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. [ABSTRACT FROM AUTHOR]