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.

Use of X-Ray Micro-Computed Tomography on Selected Upper Triassic (Rhaetian) Foraminifera From the Western Black Sea Shelf, Offshore Romania

“…However, only a few papers show both the external and internal features of a certain foraminiferal species (e.g. Trifonova 1965Trifonova , 1967Langer 1968;Fuchs 1975;Heath & Apthorpe 1986;Kristan-Tollmann 1988;Vettorel 1988;Haig & McCartain 2012). The traditional method of obtaining two-dimensional transects from three-dimensional specimens is to embed the specimen in resin and then cut it in the desirable orientation.…”