10Be exposure ages for the Late Pleistocene Gour de Tazenat maar (Chaîne des Puys volcanic field, Auvergne, France)

Abstract

Abstract Gour de Tazenat is a maar volcano on the crystalline Plateau des Domes, the uplifted margin of the Limagne Rift of the Massif Central of France, and forms one of the northernmost volcanic centers of the Chaine des Puys volcanic field. Although long recognized as a relatively young volcanic center in the area, age determinations have been elusive, with the only one quantitative estimate based upon radiocarbon ages of bulk sediments in the crater lake and extrapolation of sedimentation rates to account for the full thickness of the sediments; that age is ∼35 cal ka. Here we test application of cosmogenic 10Be exposure dating to quartz-bearing subvolcanic rocks exposed in the wall of the maar crater. Considering erosion rates (∼5 m/Myr) that we determined from 10Be data on a nearby tor (located outside the crater), and corroborated by inverted relief of older, dated lavas in the region, the 10Be data yield an age of 29–34 ka for the maar-forming eruption of Gour de Tazenat. This is consistent with the one previous quantitative estimate, and provides confidence in the age range of the maar. This age corresponds to a pulse of volcanic activity around 30 ka in other parts of the Chaine des Puys.