History and Environmental Impact of Mining Activity in Celtic Aeduan Territory Recorded in a Peat Bog (Morvan, France)

Abstract

The present study aims to document historical mining and smelting activities by means of geochemical and pollen analyses performed in a peat bog core collected around the Bibracte oppidum (Morvan, France), the largest settlement of the great Aeduan Celtic tribe (ca. 180 B.C. to 25 A.D.). The anthropogenic Pb profile indicates local mining operations starting from the Late Bronze Age, ca. cal. 1300 B.C. Lead inputs peaked at the height of Aeduan civilization and then decreased after the Roman conquest of Gaul, when the site was abandoned. Other phases of mining are recognized from the 11th century to modern times. They have all led to modifications in plant cover, probably related in part to forest clearances necessary to supply energy for mining and smelting. Zn, Sb, Cd, and Cu distributions may result from diffusional and biological processes or from the influence of groundwater and underlying mineral soil, precluding their interpretation for historical reconstruction. The abundance of mineral resources, in addition to the strategic location, might explain why early settlers founded the city of Bibracte at that particular place. About 20% of the anthropogenic lead record was accumulated before our era and about 50% before the 18th century, which constitutes a troublesome heritage. Any attempts to develop control strategies in accumulating environments should take into account past human activities in order to not overestimate the impact of contemporary pollution.

Environmental impact of early palaeometallurgy: pollen and geochemical analysis

“…This is probably related in part to the forest clearance necessary to supply energy for mining and smelting. Vegetation cover may have been drastically affected by selective deforestation, affecting especially Fagus (beech) in the Morvan (Monna et al 2004b) and at Mont Lozère (Lavoie et al in press), while Quercus (oak) was preferentially used for charcoal production in the High Aldudes Valley (Galop et al 2001;Fig. 2).…”

“…These investigations were conducted on peat cores collected in the Morvan mountains (Monna et al 2004b), in the Lozère mountains in the southern Massif Central (Baron et al 2005;Ploquin et al 2003) and in the Basque Country (Pyrénées; Monna et al 2004a; Fig. 1).…”

Reconstruction of human exposure to heavy metals using synchrotron radiation microbeams in prehistoric and modern humans

“…A rapid increase in exposure to levels of the heavy metals in the modern environment, when compared to those in prehistoric periods, may have caused adverse health effects. To investigate such a possibility, reconstruction of the exposure history of humans has recently been explored in a number of studies [3][4][5].…”

Une pollution métallique antique en haute vallée de l’Arve

“…ArcheoSciences, revue d 'archéométrie, 34, 2010, p. 197-201 F. Monna (Monna et al, 2004b) a récemment exposé les bases d'une approche résolument pluridisciplinaire de l'histoire des pollutions anciennes démontrant l'inté-rêt scientifique d'un travail concerté entre géochimistes et archéologues. Cette approche est actuellement mise en oeuvre dans le Massif Central (Baron et al, 2005, Monna et al, 2004b et les Pyrénnées (Monna et al, 2004a), mais les Alpes n'ont été que peu étudiées et les rares études sur la contamination au plomb sont restées cantonnées aux derniers siècles, que ce soit à partir d'archives glaciaires (Rosman et al, 2000) ou lacustres (Arnaud et al, 2004).…”

“…Cette approche est actuellement mise en oeuvre dans le Massif Central (Baron et al, 2005, Monna et al, 2004b et les Pyrénnées (Monna et al, 2004a), mais les Alpes n'ont été que peu étudiées et les rares études sur la contamination au plomb sont restées cantonnées aux derniers siècles, que ce soit à partir d'archives glaciaires (Rosman et al, 2000) ou lacustres (Arnaud et al, 2004). Au moins en ce qui concerne les Alpes du Nord, ce relatif désintérêt est probablement dû à la rareté de traces attestées d'exploitations anciennes.…”