Ende 2016 ist Journal 22.1 der Zeitschrift METALLA erschienen. Die Leserschaft erwartet wie üblich ein Portfolio an vielfältigen Beiträgen und Themen.
Mitterberg is the largest known Middle Bronze Age copper mining area in the Austrian Alps. During the course of the 2011 excavation campaign, a geoarchaeological investigation was conducted at the Troiboden peat bog, immediately southwest of the Mitterberg mine’s main entrance, which shows evidence of a more sophisticated ore beneficiation process with less copper loss than previously anticipated and has yet to be demonstrated at Bronze Age sites elsewhere. A portion of results of this investigation is summarized here. A sediment typology based on geoarchaological analysis is presented, and interpretations are made regarding the situation of the ore beneficiation landscape of Troiboden and its relationships both with the Mitterberg mines and its natural setting.
The abundant new crucible and slag finds from the Thier-Brauerei excavation in the center of medieval Dortmund have provided a stimulus to revive the discussion of Westphalian brass cementation technology in the Carolingian and Ottonian periods and to explore unanswered questions concerning the process and its potential outcome. A total of sixteen crucibles and slag samples from stratified deposits in the Dortmund-Thier-Brauerei and Soest Plettenberg excavations were prepared for optical and scanning electron microscopy to analyze metallic inclusions, slag phases and crucible ceramic. The copper and brass inclusions within the crucibles and their adhering slag from Dortmund show a relationship between lead and zinc contents and indicate that lead-bearing calamine ore was heated with charcoal and copper metal to produce leaded brass. Ternary Cu-Zn-Pb alloys are common for contemporary bar-shaped ingots, which supplied casting industries in early medieval Northern European towns like Hedeby and Kaupang. Concerning the zinc-rich black slag lining the interior of some crucible fragments, they regularly showed increases in lime and iron oxides in relation to the crucible ceramic and thus reflect impurities coming from the zinc ore. The lead-silicate slags often found in association with crucible finds in Dortmund have yet to have a clear interpretation; although the lead isotope analysis of crucibles and lead-silicate slag shows they may have the same source of lead, the production of the lead-silicate slag is definitely unrelated to the metallurgical process occurring inside the cementation crucibles themselves.
A total of 50 cosmetic pigments from the Royal Cemetery of the Sumerian city of Ur, Mesopotamia, now in the collections of the Penn Museum, Philadelphia, were investigated for their mineralogical, inorganic, organic and lead isotope composition. The aim of this study was to investigate the making of the pigments and to search for the origin of the material used. Main components of the green pigments were green secondary copper minerals mixed with white hydroxyapatite from bones. Copper acetates and formic acids were detected and the formation of verdigris is discussed. Black pigments mostly consist of black manganese minerals. White pigments were made of oxidized white lead minerals, while in red pigments hematite was detected. Vegetable oil or animal fats were detected in a majority of the pigment samples analyzed, and it appears that the pigments were smoothly smeared into the (shell) containers as a paste, but the modern conservation of the pigments and decomposition of the organics hinders a clear identification of the original organic components. Chemical and lead isotope analyses point to a provenance of the coloring minerals from ore deposits in Oman, on the Iranian Plateau and in southeast Anatolia.
At the confluence of Tigris and Euphrates, the Early Dynastic period was a time of great wealth and prosperity for the city of Ur and a time of secure long distance trade relations. Countless finds, which were recovered from the tombs of the Royal Cemetery of Ur are not only witnesses for an extraordinary degree of craftsmanship, they are number of precious artifacts crafted from (noble) metals and semi-precious stones. Only very few analytical investigations on these invaluable objects of enormous cultural importance were performed in the past, and those that were mostly were motivated by pressing preservation issues. Based upon the available analyses (Plenderleith, 1934, pp.294), it is apparent that there are different types of gold alloys present in the Royal Tombs and the availability of different types of gold is also supported by the textual evidence in cuneiform tablets (Reiter, 1997). Moorey (1994), however, stated that the interpretation of the textual evidence for the kinds of gold and silver and their origins is anything but simple. Visual inspection of the gold artifacts shows that there are variations of color and this should be to be expected with gold alloys: The gold objects of Ur appear yellowish, whitish and reddish with changing tints. Details of color variations must have been certainly wellknown already in early gold smithing, so that it is reasonable to assume that the different colors could have been produced deliberately. As a first stage of the larger joint venture between the Penn Museum, the Deutsches Bergbau-Museum Bochum, the Goethe-Universität Frankfurt and the British Museum, a series of non-destructive elemental analyses on selected gold and silver objects were performed in 2009 at the Penn Museum.
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