Triassic and Jurassic radiolarians

Middle and Late Triassic radiolarian faunas have been restudied, in part using new collections. On this basis a late Anisian through early Carnian quantitative biostratigraphic framework was established, using the Unitary Association (UA) method. The ranges of a total of 363 species permitted to distinguish 8 radiolarian zones and 11 subzones, as opposed to four zones used before. Radiolarian turnover and radiation, previously thought to mark the beginning of the Ladinian, is now shown to occur earlier, in the Trinodosus Zone. Subzone uaz7 permits the best correlation with the ammonoid biozonation, with the lower boundary of Reitziites reitzii Subzone. Another tie point between the ammonoid and radiolarian biostratigraphy is identified at the Ladinian/Carnian boundary, at the base of the Aon Zone and subzone uaz11, respectively. Radiolarian studies of selected Triassic localities of the Vardar Zone shed light to the rifting process of the Neotethys. Taxonomic and paleoecological studies of the exceptionally rich Late Triassic radiolarian fauna of the Mersin Melange in Turkey led to the description of 55 new species and 6 new genera.

Studies of radiolarites from the Dinaric Ophiolite Belt yielded the oldest known ages from the western Neotethys and confirmed that rifting of the Neotethys started already in the Anisian. Investigation of the Darnó and Szarvaskő Complexes led to a reinterpretation of the genesis of radiolarites in northern Hungary and the age of the early rifting process. Radiolarian biostratigraphy was also employed to refine the age of Jurassic units in the Bükk Mts and the Mónosbél and Telekesvölgy units of the Rudabánya Mts.