Plan miocène et épandages siliceux {cf. rañas) au pied des Monts Ibériques Occidentaux/Miocene planation surface and siliceous deposits on the piedmonts of the Western Iberian Ranges

Abstract

Abstract This paper links two events which seem very different : the Miocene planation surface and deposits (the Spanish "raňas "). We demonstrate the Vallesian erosion induces a thick weathering and a correlative accumulation of carbonates in the endoreic basins. During upper Miocene, the aridification and the beginning of epeirogenic movements releases the scouring of alterated materials and their deposits on the piedmonts. Here, the dating of "raňas " is not "villafranchian ", as it was estimated before. Indeed, the surface of these detrital deposits was bleached during the wet Pliocene : we find drifts coming from the upper white sands in the well-dated layers of Villarroya (-2,5 MA).