The impact of ancient iron mining and smelting on the landscape balance on Elba Island, Tuscan Archipelago, Italy

Abstract

Objectives: Elba Island (Tuscan Archipelago, Italy) was one of the hotspots of Etrusco– Roman iron metallurgy. At least since the 6th century BCE, hematite ore was extracted from the deposits on the island. The run-of-mine was at first transported to the ‘industrial’ area of the major Etruscan city of Populonia. Iron smelting on the Island started most likely in the late 4th century BCE. Production increased after the Roman occupation in the mid-3rd century BCE, peaking around the mid- to late 2nd century BCE. Afterwards, the smelting activities on Elba decreased markedly. The time lack between the onset of mining and smelting on Elba, and rather the decline in production, are attributed to a lack of fuel on the island after deforestation. A ‘deforestation’ narrative developed at least since the mid-18th century and is continuously cited until recently. Most scholars rely on the decreases in archaeological material, an ancient observation by Strabo that iron was not processed on the island, and contemporary view on Elba’s landscape. Scientific evidence of a lack of fuel, deforestation, or environmental change during the smelting period is sparse. Besides the use of wood fuel for smelting, also legacy issues are an important aspect of historical human–environment interactions on Elba. The Greek name of Elba—Aitháleia, the fuming one—and historical observations point to the emission from furnaces. Some scholars believe that the luxurious villae maritimae were constructed on Elba only after the abandonment of most smelting sites, because soot emission would have made the island uninteresting for recreation. Additionally, marine sediments and recent data from the mines suggest that (subrecent) iron production had an environmental impact on Elba. Direct evidence for such an environmental impact caused by ancient smelting is, however, not propound. Approaches: In the thesis at hand I use (i) soil chemical data from the ancient smelting site in Magazzini; (ii) geochemical analysis of sediment sequences uncovered from the Campo coastal plain; (iii) a stochastic chronological model of sediment facies sediment accumulation using cumulative probability functions of cal-14C-ages and (iv) Monte-Carlo simulations on the woodlot requirements for iron smelting and the supply of the workforce to reconstruct human-landscape interactions on Elba during the mid- to late Holocene with a clear focus on the ancient smelting period (4th century BCE – 1st century CE). The body of the thesis comprises four case studies related to the four methodical strategies. The interpretation of the results is embedded in a characterization of the ‘metallurgical landscape’ on ancient Elba and a conceptual socio-ecological model of iron as a raw material that rests on the ideas of the Vienna School.

Results: The main outcomes of the reconstruction of human–environment interactions and the impact of smelting on the landscape balance are as follows. A specific signature of ancient iron smelting is still detectable for on-site geochemical data and terrestrial sediment sequences. Soil on the smelting site are increased in As, Fe, Cu, and Ca contents and organic and pyrogenic carbon, magnetic susceptibility, and pH. The spatial variability of these activity marker points to different processes of the smelting procedure; Ca is for instance related to ashes, whereas Cu points to the the deposition of metallurgical remains, and As to run-of-mine. As the data from the smelting site differs from other archives of metallurgy on and around Elba, our record gives a specific chemical impact of iron smelting. Sedimentological and chronological data suggest that during the ancient smelting period, geomorphic activity on Elba increased clearly. Sediment layers indicating soil erosion and high magnitude floods were deposited in valleys with smelting site in upstream areas; in different sediment archives distributed over several plains and valleys on Elba, sediment accumulation and geomorphic activity increased during Etruscan/Roman times. Sedimentological evidence also implies that the palaeolandscape—especially the accessibility of different land areas limited by the distribution of wetlands—was one location factor for smelting sites. Although the impact of smelting on the landscape balance is detectable in different archives using different proxies, Roman metallurgy on Elba did not necessarily cause a lack of fuel. Our Monte-Carlo experiments of the woodlot requirements reveal that it is (very) unlikely that not fuel wood was available during Roman times. This is especially clear when assuming that Elba was autarchic regarding the food supply for metalworkers. The model suggests that the non-technical requirements for smelting importantly contributed to the overall woodland availability on Elba.

Conclusions: Sediments and soils prove to be valuable archives of the ancient smelting period. In conclusion, iron smelting on Elba during the antiquity had a remarkable impact on the landscape balance, however, without necessarily causing a lack of fuel. We therefore consider that the ‘deforestation narrative’ developed under the historical–environmental conditions of the 18th to 21st century and other reasons than deforestation might have triggered the abandonment of smelting sites in the 1st century BCE. Smelting might also have continued after the turn of eras.