A multiapproach for solving geoarchaeological problems: inferences from Roman gold mining in the Eria Valley (León)

The Eria River valley exhibits one of the largest gold mining complexes in NW Iberia from Roman age. In this study, a geoarchaeological work is presented, combining a multiapproach based on airborne LiDAR remote sensing, descriptive geology and radiocarbon dating. The studied area is characterized by the presence of a mining infrastructure comprised of hydraulic canals driving the water at different levels to the mines. Mining works were associated with Plio Quaternary raña deposits and Quaternary materials consisting of hillside and periglacial deposits, and fluvial terraces. The washing of the gold deposits used the hydraulic force to break up and drag out the sediment, giving rise to three different types of exploitation depending on the characteristics of the different materials. The results shed light on the geological materials exploited and other geographical aspects that conditioned the exploitation techniques. The work contributes to improving the knowledge about Roman gold mining and its geological context in northwest Iberia.