 The contemporary tectonic uplift of the Carpathian Mountains cut off the flow of water to the Black Sea, and the Pannonian Sea formed in the basin.Sediments were transported to the basin from the uplifting Carpathian and Dinaric mountains, with particularly deep fluvial sediments being deposited in the Pleistocene epoch during the formation of the Transdanubian Mountains.Ultimately up to of sediment was deposited in the basin, and the sea eventually drained through the Iron Gate gorge.