A coelacanthid-rich site at Hasbergen (NW Germany): taphonomy and palaeoenvironment of a first systematic excavation in the Kupferschiefer (Upper Permian, Lopingian)

Abstract

Plants, invertebrates and fish vertebrates were studied in an excavation campaign of the 30-cm-thick Upper Permian Kupferschiefer Member (Werra Formation: Lower Zechstein, Lopingian) in the Huggel (Osnabrucker Bergland, NW Germany). Taphonomy was mapped at six different planal levels on a 12 m2 area. Plant remains belong mainly to terrestrial conifers Ullmannia frumentaria (Schlotheim) and Pseudovoltzia liebeana (Geinitz), and rare Quadrocladus solmsii (Gothan and Nagelhard). Marine invertebrates consist mainly of the common nautilid Peripetoceras freieslebeni (Geinitz). Of importance is a rich fish fauna with rare skeletons of elasmobranchs Wodnika striatula Munster and Janassa bituminosa (Schlotheim) and numerous actinopterygians, dominated (83%) by Palaeoniscum freieslebeni Blainville as juvenile to adult individuals in different stages of disarticulation. Other, rarer, ray-finned species, including Pygopterus humboldti Agassiz, Platysomus striatus Agassiz, Eurysomus macrurus (Agassiz), Dorypterus hoffmanni Germar and Acentrophorus glaphyurus (Agassiz) are typical for the diverse European Late Permian Zechstein Sea fauna. Most important are concentrations of Coelacanthus granulatus Agassiz (3% of total), also represented by juvenile to adults. Fossil density variation within the Kupferschiefer reflects paleoenvironment in a shallowing-up sequence and bathymetrical change from deeper water to zones close to coastal patch reefs. The shallow-water submarine swell zone at Hasbergen can be related to uplift of the regional Huggel Horst. Charcoalified wood indicates forest fires, and palaeocurrent orientation of fossils correlates with the paleoclimatic of SW Passat wind-direction models based formerly on palaeodune analyses.