Back to sender: tectonic accretion and recycling of Baltica-derived Devonian clastic sediments in the Rheno-Hercynian Variscides

Sedimentary petrography and zircon ICP-MS laser ablation ages from synorogenic clastic sediments in the Rheno-Hercynian Belt of Germany (Rheinisches Schiefergebirge, Harz) reveal basal tectonic accretion followed by exhumation and recycling of Baltica-derived Devonian shelf sediments. The recycled sediment volume demands a substantial palinspastic addition to the passive, northern margin of the Rheno-Hercynian basin. Detrital zircon ages from the Late Carboniferous foreland basin and their possible source rocks in the South Portuguese Zone permit the same interpretation. This suggests that synorogenic sedimentation in Portugal is related, like in Germany, to the closure of the Devonian-Carboniferous Rheno-Hercynian basin and not to the closure of the Ordovician–Silurian Rheic Ocean.