The geological area of Valensole appears in the landscape as a vast sloping plane from east to west, bordered to the west by the Durance valley, to the north by the Bléone valley, to the south by the Verdon valley and to the east by the alpine foothills in Digne. This wide, open unbroken area has been cut by several rivers, the most important of which is the Asse river. During the Miocene period and Pliocene period (8 to 1.65 million years ago), the torrents deposited conglomerates (composite deposits), over nearly 2,000m² and hundreds of metres in thickness. These conglomerates, with the appearance of "a mixed-fruit-cake-pudding", are made up of pebbles rolled by the waves and consolidated by a natural cement. The visual evidence ot the Asse river and its braided course penetrating these barren and dry, almost impermeable flat-plains is clear to see. Here, natural water-springs are rare and water is precious.
The Valensole plateau-plain has been an important cultivation area for almost 2 millennia. In Gallo-Roman times, its wheat was renowned. In the 19th century, almond orchards covered a large part of its territory. From the 1920s onwards, the fruit trees were replaced by lavender fields. For the last ten years, the little lavender flowers have been losing ground to cereals following the new irrigation of part of the plateau.