CONICET | Buscador de Institutos y Recursos Humanos

Middle Devonian (Eifelian-Givetian) localities in Paraná Basin, southern Brazil are represented by São Domingos Fomation. Usually Early Givetian localities are recognized using sequence stratigraphic framework and lithological data (black shales), land plants evidence (Haplostigma sp.), or the presence/absence of Lilliput fauna and/or Extra-Malvinokafric (invasors) marine invertebrates associated (post-Kačák event). In general, these sections are palynologically poorly or barren due to coarse sandy nature and intense oxidation of Middle Devonian rocks. Here we present the first Early Givetian section in Paraná Basin based on co-occurrence of palynomorphs and land plants. The outcrop (5.5 m thick, 20 m length) named Vila Ricci is located in Ponta Grossa county (Paraná state), and composed of dark to light gray shales with parallel lamination, siltstones and fine to medium- grained sandstones. Trilobites calmoniids, crinoids (Ctenocrinus sp.) and land plants (Spongiophyton sp., Palaeostigma sp. and Haplostigma sp.) were also recognized only in the base. Several ichnofossil types and plant debris occur in the whole outcrop. Plant remains can be assigned to Plant Fragment Assemblage (PFA) taphofacies. Three productive samples were collected from the base and yielded well preserved and diverse palynoassemblages composed of miospores (e.g. Acinosporites eumammillatus, Dibolisporites farraginis, Geminospora lemurata, Grandispora pseudoreticulata, Leiotriletes balapucensis), acritarchs/prasinophytes (e.g. Arkonites bilixus, Evittia sommeri, Hemiruptia legaultii, Pterospermella pernambucensis, Unellium piriforme) and chitinozoans (Ramochitina ramosi). Similar plant and palynoassemblages were also recognized in the Angosto del Pescado (northern Argentina), Balapuca, Yesera and Mataral areas (southern Bolivia). An Early Givetian age is akin to this new plant assemblage based on palynology. [CNPq 141979/2011-9; PQ 309211/2013-1; PQ 300801/2012-2]