New 40Ar/39Ar age constraints on the timing of magmatic events in the Panagyurishte region, Bulgaria

Amphibole and mica 40Ar/39Ar ages have been determined from Late Cretaceous plutonic and volcanic successions from the Panagyurishte region (Bulgaria), which is part of the calc-alkaline to alkaline Banatite belt spreading from the Apuseni Mountains to the Black Sea and hosting world-class Cu-Au-deposits. The post-collisional magmatism is younger than early Late Cretaceous orogenic events and contemporaneous with formation of the collapse-type Srednogorie sedimentary basin. Three volcanic intercalations within the oldest sedimentary succession of the Srednogorie zone exposed along the Tolponitsa river show 40Ar/39Ar ages between 93 and 89 Ma and at ca. 86 Ma. Biotites from the Elshitsa granodiorite give an age of 86 Ma. Muscovite from an alteration zone at Elshitsa yield an age of 88 Ma. Amphiboles from a dacite porphyry from Vlaykov Vruh yield an age at 80 Ma. Biotites from the Velichkovo granodiorite give ages at 78–80 Ma.