Facies analysis of the Silurian shale-siltstone succession in Pomerania (northern Poland)

Abstract

T he Silurian deposits of Pomerania occur in the foreland of the Pomeranian Caledonides which are the Sf: continuation of the Dan-ish-North-German Caledonides. The Si lurian sequence in PomeTlinia is represented largely by graptolitic clay- and mud-shales depositcd in a hemipelagic environment. From the Wcnlock th rough Late Ludlow, slow deposition ofhemipclagic elays and muds was repeatedly interrupted by silty debris flows and turbidity currents. Many of the siltstone interbeds were reworked by bottom currents. Clastic mate-rial was sourccd from the Caledonian accretionary prism stretching along the collision zone of Baltica ftnd East Avalonia. The Siluriftn shale-sil tstone succession in Pomc111nia represents a Caledonian e)(oflyseh i.e. syn-collision clastics accumulated in a foredeep devel-oped on thc east European Croton. The diachronous appearance of siltstone inlerbeds in the gf1Iptolitic shales indicate Ihat collision be-tween Baltica and East Avalonia was associated with sinistral strike-slip movement along the edge of the east European Craton.