Around 230 million years ago, Provence was covered by a sea at the bottom of which sediments accumulated and formed the white limestones at the origin of the great massifs of the region like Mont Ventoux, Luberon, or Sainte-Victoire. The limestones were gradually covered with gray clays and green sands rich in iron atoms some 110 million years ago. When Provence emerged under a tropical climate 10 million years later, the green sands were altered by torrential rains that dissolved their components. This leaching of iron oxides gave rise to yellow and red sands colored by goethite and hematite.