Permian–Triassic A-type rhyolites from the Central Balkanides (Stara Planina Mountains), Bulgaria

Abstract

The rhyolites from the Central Balkan and Sinite Kamani areas are formed in a close time span from 254.6 to 250.7 Ma, while those next to the village of Vlado Trichkov are a little bit earlier (260.3±1.0 Ma). Both age groups follow the voluminous late Carboniferous to early Permian igneous activity that ceased around 290 Ma. The geochemical characteristics of the Vlado Trichkov dacite are comparable to those from the earlier magmatic event. On the other hand, the rocks from the Central Balkan and Sinite Kamani areas show trends of A-type granitoids. The origin of this magmatic products could be attributed to a crustal melting by mantle-derived melts, penetrating or underplating the crust in a post-orogenic setting during the initial extension and rifting, preceding the opening of the Vardar-Meliata Ocean.