The arrival of the sea in Provence

In the Miocene, 20 million years ago, the sea transgresses and covers Provence. We can now visualize its arrival in the geological layers. A first layer of green sands, corresponds to the old coastline. Glauconite, a mineral rich in iron giving this green tint, is formed in shallow waters. These sands are surmounted by a conglomerate of pebbles, sometimes green as well, carried by the arrival of the sea. Above, once the sea settled, a sedimentary rock settled: the molasse.