Discovery of trace fossils in the Weesenstein Group, Elbe Zone, Germany, and its significance for revising the Ediacaran and Ordovician stratigraphy of Saxo-Thuringia

Trace fossils are described for the first time from the Purpurberg Quartzite of the Weesenstein Group, where deposition is so far considered to be glacio-eustatic controlled during the ~565 Ma-old Weesenstein–Orellana glaciation. The mineralogically mature quartzites are locally rich in trace fossils, but the bedding plane bioturbation index is commonly less than 3. The trace fossil assemblage is of low diversity and comprises abundant Palaeophycus isp. and Palaeophycus tubularis and rare Phycodes, likely Phycodes cf. palmatus. One large Lockeia siliquaria and likely also a poorly preserved Rusophycus? isp. were found. Based on these findings and regional correlation with quartz-rich sequences of Saxo-Thuringia, an Early Ordovician age is suggested for the Purpurberg Quartzite, which can be regarded as a facies equivalent to shallow marine, quartz-rich sequences of southwestern Europe deposited along the northern Gondwanan margin during the Early Ordovician. In the light of this new insight, stratigraphic implications for the Weesenstein diamictite are also briefly discussed.