In a slight detour last week, Matt went underground in Paris to the Catacombs; ‘les vacances d’un busman’.
Extensive voids were formed during hundreds of years of mining the Eocene/Lutetian strata, the distinctive Paris Limestone. There were interesting similarities to the UK, notably early outcrop working, followed by shallow pits and subsequent ‘piliers tournés’, known as pillar and stall mining in the UK.
Napoleon ended the mining due to roof rock collapse, building damage and public outcry, but ~10% of the land area of Paris was already underlain by voids. Some of the earliest Urban Geology maps were created as a result and all excavation or foundation work was to be reported to l’Inspection Générale des Carrières de la Seine.
Major public health problems from large cemeteries led to a decision to move their contents elsewhere and the abandoned limestone mines presented an ideal location. 6 or 7 million bodies were moved into the catacombs from 1786 onwards.
Interactive ArcGIS map of the mines with links to the l’Inspection Générale des Carrières maps: https://www.arcgis.com/apps/instant/media/index.html?appid=59873b0b206e4aefae712dc2cdda200c
Further information here: https://www.youtube.com/watch?v=4CfazQ2P8D8
