Unreported Fe and Pb-Cu slag heaps in Populonia hinterland (Tuscany, Italy): quick geochemical discrimination and mapping

Luca Tinagli¹ & Irene Rocchi^1
1Department of Earth Sciences, Università di Pisa, Via S. Maria 53, 56126 Pisa, Italy.
Corresponding author e-mail: luca.tinagli@phd.unipi.it

This paper describes a topographic and geochemical quick field survey approach for the investigation of Fe and Pb-Cu slag heaps deriving from the ancient smelting of Fe-oxides and Pb(-Ag)-Cu sulfides. The quick field survey method, joined together with geochemical analyses (HH-XRF) of slags and ore samples provided: (i) the extension of the slag heaps, (ii) the environmental contextualization, (iii) the type and chemistry of the slags and ore minerals, (iv) the connection between mining and smelting sites. The several Pb-Cu slag heaps in Schiumai site (nearby Campiglia Marittima town) were described in detail, since this site is still undescribed despite its importance as one of the most extended slag deposits in the area. The other smaller slag heaps detected in the Populonia hinterland were also mapped and a general description was provided. The HH-XRF geochemical analyses, coupled with macroscopic observations, have proven to be sufficient to discriminate between Fe and Pb-Cu slags: the Fe-slags have FeO >60 wt% and Pb+Cu+Zn <700 ug/g with W anomalies; the Pb-Cu slags have FeO about 40 wt% and Pb+Cu+Zn up to 4-5 wt%. The results increase the knowledge of the distribution of archaeometallurgical sites in the Populonia hinterland area and allow to reconstruct the connection between proximal (Pb(-Ag)-Cu sulfides of Campiglia Marittima) and distal (Fe-oxides of Elba Island) mining sites related to the investigated smelting sites of Populonia hinterland.

metallurgical slags, slag heaps survey, hematite, Populonia hinterland, Campiglia Marittima mining district, HH-XRF.