Exotic glass types and the intensity of recycling in the northwest Quarter of Gerasa (Jerash, Jordan)

Major and trace elements are presented for 149 glass fragments ranging in date from the Roman to Early Islamic periods (1st – mid-8th centuries CE), excavated during the Danish-German Jerash Northwest Quarter Project's fieldwork between 2011 and 2016. The results confirm a clear dominance of Levantine glass types, but also reveal 12 glasses of Egyptian and Mesopotamian compositions recovered from two houses destroyed by the major earthquake which hit parts of the Levant in January 749 CE. These closed and undisturbed contexts from the final phase of occupation reveal the presence of relatively more pristine Levantine as well as imported material that is less visible in earlier contexts in the Gerasa assemblage, where the recycling indexes are high and chemical signatures of any exotic glass were largely lost due to remelting and their dilution by the overwhelming quantities of glass produced in the Levantine region. This emphasizes that imported glass may frequently be underestimated or even invisible in glass compositional studies, depending on the archaeological context sampled and the approach taken to artifact quantification. Levantine glass was attributed to Roman, Late Roman (Jalame) and Byzantine/Early Islamic (Apollonia) productions based primarily on MnO, Al_{2}O_{3} and Na_{2}O concentrations, which offered an advantage over previous approaches. While colorants in weakly colored glass indicate recycled material, their concentrations are sensitive to context, with higher concentrations in the early periods when the use of intentionally colored glass was more frequent. We have therefore developed the concept of the intensity of recycling, which was estimated using components modified during prolonged melting, such as K_{2}O, P_{2}O_{5} and Cl. A pronounced enrichment in CaO, also dependent upon the intensity of recycling, may affect the assignment to compositional groups and should be taken into consideration in future. Recycling in Gerasa appears to have been more intensive than was the case for cities closer to the primary production centers on the Mediterranean coast, consistent with the view that the dependency on recycling increases further away from the source of the primary material. In contrast, the cities in the coastal plain could readily exploit the marine transportation network, which appears to have played a major role in the distribution of raw glass

Copper-based metalwork in Roman to early Islamic Jerash (Jordan): Insights into production and recycling through alloy compositions and lead isotopes

Metallographic, chemical and lead isotopic analyses of copper-based artefacts recovered from the Northwest Quarter in Jerash (ancient Gerasa) in Jordan provide new information on the civic life and material culture from a key urban site in the Roman Empire's eastern provinces. The samples span the city's occupation from its flourishing under Roman rule into the Byzantine and early Islamic periods. We examined 49 copper-based artefacts using reflected light microscopy and micro-X-ray fluorescence. A subset of these artefacts was analysed by electron microprobe spectroscopy for major and minor elements at higher spatial resolution, and by multi-collector inductively coupled plasma mass spectrometry for lead isotopes. Results imply that binary bronze dominated the Roman period, (leaded) brass characterised the Byzantine period, while tin-containing alloys were prevalent during the Islamic period. Lead isotopes suggest that during the Roman and Byzantine periods some of the metal in Jerash came from European and/or Mediterranean sources, while copper used during the Islamic period may have been sourced more locally from Timna. The changes in alloy types and lead isotopes suggest that recycling of metals took place in Jerash possibly as early as the Roman period and more frequent from the Byzantine period onwards

A Roman provincial city and its contamination legacy from artisanal and daily-life activities

Funding: This project was supported by the Carlsberg Foundation (R.R., www.carlsbergfondet.dk, Grant CF14-0467), Danish National Research Foundation (R.R., www.dg.dk, Grant 119), the Deutsche Forchungsgemeinschaft (A.L., https://www.dfg.de/, grant nos LI978/4-1 and LI978/4-2), the Deutscher Palästinaverein (A.L., https://www.palaestina-verein.de/), the Danish EliteForsk Award (R.R., https://ufm.dk/forskning-og-innovation/forskningsformidling/eliteforsk, grant 4094-00077B), and H. P. Hjerl Hansens Mindefondet for Dansk Palæstinaforskning (RR).Roman metal use and related extraction activities resulted in heavy metal pollution and contamination, in particular of Pb near ancient mines and harbors, as well as producing a global atmospheric impact. New evidence from ancient Gerasa (Jerash), Jordan, suggests that small-scale but intense Roman, Byzantine and Umayyad period urban, artisanal, and everyday site activities contributed to substantial heavy metal contamination of the city and its hinterland wadi, even though no metal mining took place and hardly any lead water pipes were used. Distribution of heavy metal contaminants, especially Pb, observed in the urban soils and sediments within this ancient city and its hinterland wadi resulted from aeolian, fluvial, cultural and post-depositional processes. These represent the contamination pathways of an ancient city-hinterland setting and reflect long-term anthropogenic legacies at local and regional scales beginning in the Roman period. Thus, urban use and re-use of heavy metal sources should be factored into understanding historical global-scale contaminant distributions.Publisher PDFPeer reviewe

Bronze Age antler axes – dating and depositional context

Breonze Age antler axes – dating and depositional context Antler axes are typically associated with the Mesolithic, but this article presents a group of antler axes from the Danish Bronze Age, when this artefact type surprisingly turns up again after an absence from the tool inventory of more than 2000 years (fig. 1). These artefacts may be found in pits in a settlement context, but the typical finds contexts for the 155 recorded Bronze Age antler axes are rivers/watercourses, lakes and wetland areas, where the axes have been deposited individually, in line with the Bronze Age’s other major group of singly-deposited objects (figs. 2-3). This close relationship with water is linked to the European river finds, as antler axes are not solely a Danish phenomenon but are found across large parts of Europe during the Bronze Age, with the axes typically being deposited singly in running water. In both a Danish and a European context, the axes disappear again in the Iron Age. This article gives an account of the Danish antler axes in relation to their distribution, finds circumstances and typo­logical characteristics, together with a couple of metal analyses and several new 14C dates for antler axes. The antler axes from the Bronze Age vary in appearance; they may or may not be polished and may or may not be ornamented. They do though have certain features in common, for example they are characterised by a down-turned butt. The shaft-hole can either be round or rectangular and is located a long way back on the axe. They were typically hafted as axes rather than adzes, and their ornamentation frequently consists of point-circle motifs, where pitch has been inlaid to give contrast (figs. 4-8). In a very few cases, metal may form part of the ornamentation. Two results are presented here of micro-XRF analyses of, respectively, inlays of tin and bronze (figs. 9-14). A significant part of the project ­focussed on dating of the Bronze Age antler axes. Only a couple of dates had been published previously, both of which fell in the Late Bronze Age. The new dates clearly show, however, that antler axes are a very consistent phenomenon through both the Early and the Late Bronze Age. Dating involves drilling material out for analysis, and in the case of antler and bone there is sometimes a requirement for a sample of as much as 600-800 mg for a date to be obtained. To avoid drilling unnecessary holes in the often aesthetically impressive and eminently exhibitable artefacts such as these, a staged methodological approach was adopted in this project, which involved two-step sampling for radiocarbon dating. Firstly, a very small sample of 5-20 mg was taken for a so-called EA-IRMS analysis. This reveals the preservation condition of the material and thereby the amount of material required to obtain an actual 14C date. In all cases, this preliminary analysis showed that only 100 mg of material had to be drilled out for the actual dating process. This method can therefore be warmly recommended for the dating of bone and antler objects such as these (figs. 15-16). The dates have revealed that antler axes are present in both the Early and the Late Bronze Age. Moreover, the dates could be used in a clarification of the depositional circumstances. As already mentioned, the antler axes typically represent single depositions, but sometimes two axes are found relatively close together and, based on the finds circumstances, are therefore interpreted as single-type depositions. It has now been possible in some cases to date both axes: For example antler axes found together in sediment dug up during the dredging of rivers/watercourses (Ryå and Odense Å), or discovered close together during peat cutting (Jorløse Mose) or within the same area of reclaimed lake (Søborg Sø). The dates obtained in these cases suggest that these finds represent repeated single depositions within the same area rather than simultaneous deposition of two axes. The phenomenon of returning, in a depositional context, to specific areas in the natural landscape, sometimes at intervals of several hundred years, appears to be a general feature of the Bronze Age – both in Denmark and in Europe as a whole (figs. 17a-22).Bronze Age antler axes – dating and depositional context Antler axes are typically associated with the Mesolithic, but this article presents a group of antler axes from the Danish Bronze Age, when this artefact type surprisingly turns up again after an absence from the tool inventory of more than 2000 years (fig. 1). These artefacts may be found in pits in a settlement context, but the typical finds contexts for the 155 recorded Bronze Age antler axes are rivers/watercourses, lakes and wetland areas, where the axes have been deposited individually, in line with the Bronze Age’s other major group of singly-deposited objects (figs. 2-3). This close relationship with water is linked to the European river finds, as antler axes are not solely a Danish phenomenon but are found across large parts of Europe during the Bronze Age, with the axes typically being deposited singly in running water. In both a Danish and a European context, the axes disappear again in the Iron Age. This article gives an account of the Danish antler axes in relation to their distribution, finds circumstances and typo­logical characteristics, together with a couple of metal analyses and several new 14C dates for antler axes. The antler axes from the Bronze Age vary in appearance; they may or may not be polished and may or may not be ornamented. They do though have certain features in common, for example they are characterised by a down-turned butt. The shaft-hole can either be round or rectangular and is located a long way back on the axe. They were typically hafted as axes rather than adzes, and their ornamentation frequently consists of point-circle motifs, where pitch has been inlaid to give contrast (figs. 4-8). In a very few cases, metal may form part of the ornamentation. Two results are presented here of micro-XRF analyses of, respectively, inlays of tin and bronze (figs. 9-14). A significant part of the project ­focussed on dating of the Bronze Age antler axes. Only a couple of dates had been published previously, both of which fell in the Late Bronze Age. The new dates clearly show, however, that antler axes are a very consistent phenomenon through both the Early and the Late Bronze Age. Dating involves drilling material out for analysis, and in the case of antler and bone there is sometimes a requirement for a sample of as much as 600-800 mg for a date to be obtained. To avoid drilling unnecessary holes in the often aesthetically impressive and eminently exhibitable artefacts such as these, a staged methodological approach was adopted in this project, which involved two-step sampling for radiocarbon dating. Firstly, a very small sample of 5-20 mg was taken for a so-called EA-IRMS analysis. This reveals the preservation condition of the material and thereby the amount of material required to obtain an actual 14C date. In all cases, this preliminary analysis showed that only 100 mg of material had to be drilled out for the actual dating process. This method can therefore be warmly recommended for the dating of bone and antler objects such as these (figs. 15-16). The dates have revealed that antler axes are present in both the Early and the Late Bronze Age. Moreover, the dates could be used in a clarification of the depositional circumstances. As already mentioned, the antler axes typically represent single depositions, but sometimes two axes are found relatively close together and, based on the finds circumstances, are therefore interpreted as single-type depositions. It has now been possible in some cases to date both axes: For example antler axes found together in sediment dug up during the dredging of rivers/watercourses (Ryå and Odense Å), or discovered close together during peat cutting (Jorløse Mose) or within the same area of reclaimed lake (Søborg Sø). The dates obtained in these cases suggest that these finds represent repeated single depositions within the same area rather than simultaneous deposition of two axes. The phenomenon of returning, in a depositional context, to specific areas in the natural landscape, sometimes at intervals of several hundred years, appears to be a general feature of the Bronze Age – both in Denmark and in Europe as a whole (figs. 17a-22)

Granites and Granophyres of the Bushveld Complex, South Africa:A review

A major outstanding question concerning the Bushveld Complex of South Africa is the genetic relationship between the granites (Lebowa Granite Suite, LGS) and granophyres (Rashoop Granophyre Suite, RGS), and their relation to the underlying layered mafic-ultramafic intrusion (Rustenburg Layered Suite, RLS). Here, we present new bulk rock major and trace elements, as well as Nd and Hf isotopes for 35 samples from the LGS (Nebo Granite) and RGS (Stavoren Granophyre and Zwartbank Pseudogranophyre) and combine this with published data to form a comprehensive dataset. The LGS and RGS range from ferroan to peraluminous compositions. Relative to the bulk continental crust, the granite and granophyres are depleted in Sc, V, Ti, P, Cr, and Sr, and either similar or enriched in other trace elements. εHf and εNd values (at 2055 Ma) show narrow ranges between −9.1 ± 0.8 to −6.8 ± 0.7 and − 6.0 ± 0.3 to −5.1 ± 0.6, respectively, across hundreds of kilometres, although higher εNd values have been reported previously (up to +5.2). These isotopic compositions correspond to published values for the RLS. Thus, the major element and isotopic composition as well as general trace element trends observed for LGS and RGS are consistent with derivation through fractional crystallization of basaltic magmas. A Rayleigh fractionation model for trace elements and major element mass balance suggest that c. 20% granite can be produced from fractional crystallization of such magmas. Multiple lines of evidence suggest that the granitic magmas mainly evolved in underlying, staging magma chambers rather than in the RLS chamber itself. This includes evidence for magma mixing in a newly identified transition zone separating RLS and LGS, the finding of zircon antecrysts in LGS and RGS, and the replenished and tapped nature of the RLS chamber

Matrilocality in the Middle Period in San Francisco Bay? New Evidence from Strontium Isotopes at CA-SCL-287

We explore strontium (Sr) isotope analysis as a means to reconstruct ancient migration patterns of individuals at SCL-287, a Middle Period site in southern San Francisco Bay. Comparison of Sr isotopes from rst molars to that of bone suggests that males frequently immigrated to the site, while all females were born at or near the site. This pattern is consistent with a preference for matrilocal post-marital residence patterns. At the same time, analysis of third molars indicates that individuals frequently shifted residence during early teenage years, even those who were born and lived as adults at SCL-287. While adult residence shifts are commonly reported in the ethnography of Central California, matrilocality is not. In this respect, isotopic analyses allow us to generate new hypotheses about ancient migration patterns in prehistory independent of those reported in the ethnographic literature

Matrilocality in the Middle Period in San Francisco Bay? New Evidence from Strontium Isotopes at CA-SCL-287

We explore strontium (Sr) isotope analysis as a means to reconstruct ancient migration patterns of individuals at SCL-287, a Middle Period site in southern San Francisco Bay. Comparison of Sr isotopes from rst molars to that of bone suggests that males frequently immigrated to the site, while all females were born at or near the site. This pattern is consistent with a preference for matrilocal post-marital residence patterns. At the same time, analysis of third molars indicates that individuals frequently shifted residence during early teenage years, even those who were born and lived as adults at SCL-287. While adult residence shifts are commonly reported in the ethnography of Central California, matrilocality is not. In this respect, isotopic analyses allow us to generate new hypotheses about ancient migration patterns in prehistory independent of those reported in the ethnographic literature

'Alexandrian' glass confirmed by hafnium isotopes.

Archaeological glass contains information about the movement of goods and ancient economies, yet our understanding of critical aspects of the ancient glass industry is fragmentary. During Roman times, distinct glass types produced in coastal regions of Egypt and the Levant used evaporitic soda (natron) mixed with Nile-derived sands. In the Levant, furnaces for producing colourless Roman glass by addition of manganese have been uncovered, whereas the source of the desirable antimony-decolourised Roman glass remains an enigma. In the Edict of Diocletian, this colourless glass is listed as "Alexandrian" referring to Egypt, but its origin has been ambiguous. Previous studies have found overlapping strontium and neodymium isotope ratios for Levantine and Egyptian glass. Here, we confirm these findings and show for the first time, based on glasses from the ancient city of Gerasa, that hafnium (Hf) isotopes are different in Egyptian and Levantine natron glasses, and that Sb Roman glass is Egyptian. Our work illustrates the value of Hf isotopes in provenancing archaeological glass. We attribute the striking difference in Hf isotopes of Egyptian versus Levantine glasses to sorting of zircons in Nile sediments during longshore drift and aeolian transport along the south-eastern Mediterranean coast leaving behind a less juvenile fraction