Contact: Kea Giles
Geological Society of America
Caption: Hydraulic gold mining by Romans nearly 2,000 years ago left this dramatic example of human modification of the landscape at Las Médulas, Spain, a UNESCO World Heritage Site. Water obtained from surrounding mountainous watersheds was used to undermine the >100-m-thick Miocene alluvial fan sediments here until they collapsed -- a process called ruina montium, loosely translated as ruin the mountain -- and then washed to separate the gold. Tailings total ~90 Mm3. Photo by Justino Diez.
Credit: Photo by Justino Diez.
Usage Restrictions: Credit to author and mention of the article in the December GSA Today.
Related news release: GSA Today: Human transformation of land threatens future sustainability?