Early Cretaceous (Valanginian and Hauterivian) belemnites and organic-walled dinoflagellate cysts from a marine hydrothermal vent site and adjacent facies of the Mecsek Mts., Hungary

The first record of belemnites from fossil hydrothermal vent sites in the Mecsek Mountains of Hungary emphasizes the occurrences of belemnites in Mesozoic chemosynthetic-microbial based ecosystems reported only from cold seep carbonates to date. From the outer shelf-upper bathyal (<300 m) hydrothermal vent site latest Valanginian - Early Hauterivian taxa Adiakritobelus (?), Hibolithes, Duvalia, and Pseudobelus (belemnites) and organic-walled dinoflagellate cysts (a.o. Spiniferites dentatus) are reported. The laterally extending hemipelagic facies yielded latest Berriasian and earliest Valanginian taxa, like: Duvalia, Pseudobelus, and Berriasibelus. The reported belemnite assemblage from this vent site and its coeval beds dated the time span of the iron-ore formation and venting more precisely, between the Early Valanginian and earliest Hauterivian. The belemnite and dinoflagellate cyst assemblages are typical of the Mediterranean Province of the Tethyan Realm.