Lower Ordovician conodonts from the G-14 well, Baltic Sea (Germany)

The offshore G-14 well is situated in the Baltic Sea north of the island of Rügen (Germany). Its Lower Ordovician strata (upper Tremadoc to lower Llanvirn) yielded conodonts exclusively of Baltic affinity, which permit a precise age determination and correlation to the strata in Scandinavia and northern Poland. The newly recovered conodont faunules from the Lower Ordovician limestones and calcareous grey shales in the G-14 well can be assigned to the Paltodus deltifer and the upper Paroistodus proteus conodont Zone respectively. The uppermost part of the youngest limestone unit (Komstad Limestone) in the well can be correlated with the Lenodus antivariabilis and L. variabilis conodont zones. Between the two carbonate units, calcareous shales and siliciclastic shales of the Tøyen Shale Formation are intercalated yielding respectively conodonts, chitinozoans and graptolites which suggest late Tremadocian to early Arenigian ages for these sediments. Three faunal hiatus were confirmed: At the Tremadoc-Hunneberg boundary, where the lower two subzones of the Paroistodus proteus conodont Zone are absent; between the Tøyen Shale Formation and the overlying upper Arenigian Komstad Limestone; and above the Komstad Limestone with the Didymograptus artus and D. murchisoni graptolite zones absent signifying an extensive stratigraphic hiatus between the Komstad Limestone and the overlying Dicellograptus Shale Formation.