The Lower Palaeozoic now fully cored and logged on Bornholm, Denmark

Abstract

A 558 m long, complete section of the Lower Palaeozoic succession preserved onshore southern Bornholm has been compiled from five fully cored scientific wells, carried out between 2005 and 2012. The scientific programme included coring and geophysical logging of the five scientific wells that yielded a total of c. 750 m of partially overlapping cores as well as re-logging of water wells and acquisition of shallow seismic data. The last well drilled, the Sommerodde-1, cored the youngest preserved Silurian strata on Bornholm including strata not exposed in outcrops. The well penetrated 168.1 m of Silurian shales, 42.7 m of Upper Ordovician shales and 27.9 m of Alum Shale before it terminated at a depth of 250.3 m in the Lower Cambrian Norretorp Member of the Læså Formation. Th e Sommerodde-1 well documents that the Lower Silurian Cyrtograptus shale is at least 91.7 m thick and that the Rastrites shale is 76.4 m thick. The complete Lower Cambrian succession has previously been covered by the 316.0 m deep Borggård-1 well that terminated in basement rocks (Nielsen et al. 2006).