Ground Penetrating Radar prospection at the charterhouse of Bourgfontaine

The charterhouse of Bourgfontaine was a major foundation, with approximately 24 brothers living in separate cells. An early modern bird's-eye view of the monastery gives us a sense of its scale, but no details. Two GPR surveys (225 and 250 MHz) were carried out: the first, in the area of the chapel behind the church, the second, in a rectangular zone of 30 m × 50 m in the great cloister. All the data were processed as a 3D cube and the time slices corresponding to a depth varying between 0.7 m and 1.35 m give surprisingly clear evidence of regular structures. The superposition of the surveyed zone with a plan extrapolated from the engraved view is stunning, allowing for interpretation as three monastic cells and foundations of part of the great cloister. This is an excellent example of the ways in which geophysical prospection and archaeology can complement one another.