Puy de Clierzou, Volcanic dome in Chaîne des Puys, France

Puy de Clierzou is a trachytic lava dome in the Chaîne des Puys, rising to 1,199 m on the commune of Orcines, about 10 km west of Clermont-Ferrand. Its lower flank holds a line of dark openings cut into a pale rock face, the old quarry cavities, with loose grey stones and shrubs below; a pale dirt path crosses the slope past them, and white grazing animals are scattered over the grassy upper slope above the wooded sides.

The dome is about 11,000 years old, part of the Chaîne des Puys in the Massif central. In the Early Middle Ages, quarries were dug near its summit to extract trachyte for Merovingian sarcophagi. A research project on this trachyte, involving archaeologists, geologists and stonecutters, planned excavations on its slopes from 6 to 10 November 2017, supervised by INRAP archaeologists, to probe cavities used as quarries.

The cavities near the summit are old quarries cut in the Early Middle Ages to extract trachyte for Merovingian sarcophagi. Since 2017 the collective research project "Trachyte" has studied this stone, its extraction and the spread of its products from Antiquity to modern times, with archaeologists, geologists and stonecutters working together.

The climb starts from the south, following a path through forest; at the foot of the volcano the route continues on a steep, difficult path to the summit. No marked trail leads up from Orcines itself. Sturdy footwear is needed for the loose, uneven ground.

The cavities near the summit were dug as quarries in the Early Middle Ages to extract trachyte for Merovingian sarcophagi. A research project on this stone, involving archaeologists, geologists and stonecutters, planned a dig on the slopes from 6 to 10 November 2017 to probe several of these quarry cavities, supervised by INRAP archaeologists.