Lochkovian (Lower Devonian) marine-deposits from the Rio Malinfier West section (Carnic Alps, Italy)

Carlo Corradini (1), Maria G. Corriga (1), Monica Pondrelli (2), Paolo Serventi (3), Luca Simonetto (4) & Annalisa Ferretti (3)
(1) Dipartimento di Scienze Chimiche e Geologiche, Università di Cagliari, Cittadella Universitaria (Blocco D) - SS. 554 bivio per Sesto, I-0942 Monserrato (CA), Italy. (2) International Research School of Planetary Sciences, Università d’Annunzio, viale Pindaro 42, I-65127 Pescara, Italy. (3) Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, via Campi 103, I-41125 Modena, Italy. (4) Museo Friulano di Storia Naturale, via Sabbadini 22-32, I-33100 Udine, Italy. Corresponding author e-mail: corradini@unica.it.

The Rio Malinfier West section in the central Carnic Alps provides important data on the evolution of the Lochkovian (Lower Devonian) sedimentary basins of the Variscan belt. An exposure of about 100 m comprises five lithostratigraphic units (Alticola, Rauchkofel, Nölbling, La Valute and Findenig formations) spanning in age from the latest Silurian to the Early Devonian. The complex structural setting of the section results from a main fault dividing the succession in two separate segments. A precise lithological characterization was carried on at a macro- and micro-scale. Macrofauna includes, among others, abundant cephalopods and crinoids (loboliths). The biostratigraphic assignment to the uppermost Silurian-lowermost Devonian (Lochkovian) was possible based on a moderately abundant conodont fauna, that provided thirty-two taxa belonging to thirteen genera, among which the new species Zieglerodina schoenlaubi. The Rio Malinfier West section testifies that a differentiation between shallow and deep water parts of the Devonian basin was already present during Lochkovian times, prior to the establishment of the conditions enabling the colonization of the well-known upper Lower-Middle Devonian reef buildings.

stratigraphy, microfacies analysis, taxonomy, conodonts, Devonian.