 Although a warming period 20,000 years ago rapidly melted the glaciers, they advanced again 16,000 and 12,000 years ago.The Salzach-Enns-Mariazell-Puchberg Fault (SEMP) is the largest in the Northern Calcareous Alsps.The Pols, Lavant, Mur, Murz, Isel and Moll valleys are all examples of strike-slip faults.