The Middle Silurian from Bornholm (Denmark) - sedimentology, petrology andage

The youngest Palaeozoic deposits of Bornholm are exclusively exposed on the sea floor at its southeastern coast. Six lithotypes are recognized and gen etically interpreted: (1) laminated siltstones, (2) mudstones, (3) micro-sc ale flaser to lenticular bedded siltmudstones, (4) limestones, (5) graded s andstones and (6) tuffs. Palaeoenvironmental interpretation suggests an off shore deposition in a deep-water foreland basin influenced by gravity curre nts and associated sediment reworking processes. The graptolite assemblages in the mudstones and Pb-Pb dating of single zircons from the tuffs indicat e a Late Wenlock (Silurian) age. The influence of Caledonian orogenesis on sedimentation, palaeoenvironment and provenance of the Middle Silurian depo sits on Bornholm as well as the geological development at the southwest mar gin of Baltica are discussed generally.