20 million years ago the Alps were formed, in the Mediterranean area was produced a new rising heat from the Earth's mantle which resulted in the buckle and rupture of the European crust from which detached the Sardinian-Course block, the micro Sardinian plate did pin on the Ligurian Gulf executing a counterclockwise rotation of 50° and forming the Ligurian Sea. The sea covered the hill of Turin, the Langhe, Montferrat and the Po Valley. The rotation of the Corsica-Sardinia block opposed by the African block produced a pressure that gave rise to the Apennines. 8 million years ago to the east of the Corsica-Sardinia block opened wide north-south divide that separated the Italian peninsula from Corsica and Sardinia, this gap widened to become the Tyrrhenian Sea. In the period from 7 to 5 million years ago the Mediterranean Sea was closed and remained isolated from the Atlantic Ocean. This resulted in the increase of the temperature of the water that turned the Mediterranean into a low-salt lake with many areas dried up, this condition lasted for several hundreds of thousands of years was deposited sediment type saline evaporites. Subsequently, the Mediterranean Sea was opened, and the ocean water began to circulate between the Alps and the Apennines had formed a triangular gulf that covered the entire Po Valley. Due to the continuous lifting of the Alps and the Apennines to the sea withdrew from this gulf and the accumulation of sediments carried by the rivers gave rise to a flood plain which corresponds to the Po Valley. The marine deposits of this period are visible in the area of Asti.