Pyrometallurgical relics of Pb–Cu–Fe deposits in south-eastern Germany: An exploration tool and a record of mining history

Pyrometallurgical relics from smelting of iron as well as base metal ores are mineralogically and chemically investigated and dated using the radiocarbon method and optically stimulated luminescence. This study addresses the question whether these pyrometallurgical remains may be used as an exploration tool enabling geologists to discriminate between false and true gossans. Moreover, these investigations make a historical contribution and demonstrate how mining and smelting activities spread across NE Bavaria, Germany.Iron minerals in slags may be used to interpret the physicochemical conditions during which these artifacts formed, while Ca–Mg–Fe silicates provide additional information serving as a rough indicator for stratabound ore deposits. Multicolored glassy smelting residues and secondary minerals staining slags may be taken as an indication of the existence of pyrite-bearing Cu ore deposits. Slags originating from false gossans are enriched in P and Mn, with base metal contents not exceeding crustal background values. True gossans evolving from SEDEX Fe deposits are rich in Fe and Mn. Vein-type siderite deposits create slags rich in Pb, Cu, Zn and Sn. Around 400 BC, Celtic miners headed N following the Regensburg Embayment where soft iron ores were easily accessible. From 700 to 1000 AD they entered the densely forested NE Bavarian Basement for firewood to run the kiln. Between 900 AD and 1630 AD siderite veins and SEDEX Fe deposits were exploited in NE Bavaria. It was not until the 17th century that stratabound sulphidic ores were discovered in this region.