Gold-bearing Plio-Quaternary deposits: insights from airborne LiDAR technology into the landscape evolution during the early Roman mining works in north-west Spain

Abstract

This article focuses on the characterization of auriferous deposits, identification of hitherto unknown Roman mining infrastructure remains, and the early attempts of exploitation carried out in north-west Iberia. The research has combined airborne laser scanning (LiDAR) and field prospection to explore the geomorphological signature and landscape transformation resulting from Roman mining works in two unknown sectors of the western Duero Meseta. The integration of geological and remote sensing information contributed to extend the Roman's mining domains, traditionally focused on the river headwaters of the north-west. The article explores the complex hydraulic system developed in the Jamuz and lower sector of the Eria river valleys, as well as the evidence of open-cast mining and their relationship with the Roman army. The results suggest that the highly dispersed and reduced dimensions of the mining sites correspond to a selected method of gold prospection, employed for the identification of viable exploitation sectors. Thus, the initiation of the mining works could have started in the Jamuz valley and developed systematically in this area, to subsequently spread towards the upstream sectors and nearby valleys. This research contributes to gain new insights into the extension and complexity of the mining infrastructure, indicating the importance of the gold-bearing raña deposits within the framework of Roman gold mining in north-west Spain.