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The sequence of Permian volcanic and volcaniclastic rocks (up to 2 km thick) in the Sirinia Basin (Svinița-Svinecea Mare sedimentary zone) of the Upper Danubian Units, South Carpathians, is considered to be the product of subaqueous volcanism passing into a subaerial volcanism and subsequent deposition by debris flow. The investigated volcano-sedimentary rocks are composed of a rhyolitic clastic framework embedded within a fine-grained matrix. The electron probe microanalyses of monazites in the rhyolite clasts and in the volcaniclastic matrix yielded a U-Th- total Pb mean age of 296±3.2 Ma. This result is the first to constrain the age of the volcanic activity event recorded in the volcaniclastic rocks of the Sirinia Basin. The monazite age also estimates the maximum depositional age of the volcano-sedimentary rocks as not older than early Permian (middle Asselian). [ABSTRACT FROM AUTHOR]

Abstract: This paper reports the results of CHIME (chemical Th–U–Pb isochron method) dating of detrital monazites from Carboniferous sandstones in the Upper Silesia Coal Basin (USCB). A total of 4739 spots on 863 monazite grains were analyzed from samples of sandstone derived from six stratigraphic units in the sedimentary sequence. Age distributions were identified in detrital monazites from the USCB sequence and correlated with specific dated domains in potential source areas. Most monazites in all samples yielded ca. 300–320 Ma (Variscan) ages; however, eo-Variscan, Caledonian and Cadomian ages were also obtained. The predominant ages are comparable to reported ages of certain tectonostratigraphic domains in the polyorogenic Bohemian Massif (BM), which suggests that various crystalline lithologies in the BM were the dominant sources of USCB sediments. [Copyright &y& Elsevier]