Trace fossils from the Mississippian of the Piaskowa Góra section (the Intra-Sudetic Basin, SW Poland)

Abstract

Eight ichnotaxa and enigmatic tubular forms were discovered and described for the first time from clastic deposits (the Culm facies) of the uppermost part of the Szczawno Formation (upper Mississippian) from in the Piaskowa Góra section in the northern part of the Intra-Sudetic Basin near Wałbrzych. The trace fossils are represented mostly by pascichnia and less numerous domichnia, fodinichnia and repichnia. Psammichnites plummeri and numerous Phycosiphon isp. are the most common ichnotaxa. They are accompanied by Archaeonassa fossulata, Beaconites cf. capronus, Curvolithus multiplex, Dictyodora liebeana, Palaeophycus isp., and Planolites isp. D. liebeana is described for the first time from the lower Serpukhovian. Most components of the ichnoassemblage are typical of the Cruziana ichnofacies, but the co-occurrence of Dictyodora and Phycosiphon could indicate a transition to deeper environmental settings (the Zoophycos ichnofacies). The lithological features as well as the accompanying trace fossils, wrinkle structures and floral remains of Archaeocalamites indicate rapid sedimentation, alternating with more tranquil periods of sedimentation, in an intermediate environment between the lower offshore (the distal Cruziana ichnofacies) and the fan-delta slope (below the wave base, the Zoophycos ichnofacies). The studied trace fossils and palynological data indicate that marine conditions in the Wałbrzych area in the Mississippian prevailed locally until the early Sepukhovian.