CNRS—The deepest layers of carbon-14 dated ice found in the Col du Dôme of the Mont Blanc glacier in the French Alps provide a record of atmospheric conditions in the ancient Roman era. and Imperial period (between 0 and 200 A.D.) Romans extracted lead ore (containing silver) to produce the lead needed to make plumbing and silver for coins. The silver was extracted from the lead by heating the ore to a temperature of 1200°C, releasing significant amounts of lead into the atmosphere. While this was already documented in continental peat records, obtaining global data at the European level was difficult. ____________________________________________________________Article Source: CNRS news release*This laboratory is part of the Observatoire de sciences of the Université de Grenoble.