Jurassic granitoid magmatism in the Dinaride Neotethys: geochronological constraints from detrital minerals

Abstract

Three independent single-grain geochronometers applied to detrital minerals from Central Dinaride sediments constrain the timing of felsic magmatism that associated the Jurassic evolution of the Neotethys. The Lower Cretaceous clastic wedge of the Bosnian Flysch, sourced from the Dinaride ophiolitic thrust complex, yields magmatic monazite and zircon grains with dominant age components of 164 ± 3 and 152 ± 10 Ma respectively. A unique tephra horizon within the Adriatic Carbonate Platform was dated at 148 ± 11 Ma by apatite fission track analysis. These consistent results suggest that leucocractic melt generation in the Central Dinaride segment of the Neotethys culminated in Middle to Late Jurassic times, coeval with and slightly post-dating subophiolitic sole metamorphism. Growth of magmatic monazite and explosive volcanism call for supra-subduction-zone processes at the convergent Neotethyan margin. New compilation of geochronological data demonstrates that such Jurassic felsic rocks are widespread in the entire Dinaride–Hellenide orogen.