Chemical and mineralogical characterization of Aguada Portezuelo pottery from Catamarca,north-western Argentina: PIXE,XRD and SEM-EDS studies applied to surface pre- and post-firing paints,slips and pastes

Particle-induced X-ray emission (PIXE), X-ray diffraction (XRD), electron microprobe analysis (EDS) and scanning electron microscopy (SEM) analytical techniques were used to characterize surface paints in pre- and post-fired Aguada Portezuelo decorated pottery. Surface paintings in black, white, red, brown, burgundy and ochre were analysed. Major, minor and trace elements were detected by PIXE, whereas XRD and SEM-EDS gave information on the main mineral phases and the characteristic morphology for each analysed pigment. The results obtained indicate that the main colour groups can be easily discriminated by PIXE, and they are characterized by only one pigment for each colour: hematite (red) and manganese mineral oxides (black), respectively, whereas white pigments are characterized by calcite, ghelenite and gypsum.     

Pre-Hispanic gold pieces of an enigmatic archaeological finding in Medellín,Colombia: A glance at an archaeometric analysis

The study analysed pre-Hispanic gold objects found within a surprising archaeological finding of a structure that likely served as a funeral pyre in Medellín, Colombia. ¹⁴C analyses of the site's organic materials dated the structure to the fifth century ce . The metal objects were subjected to X-ray diffraction (XRD), energy-dispersive X-ray fluorescence (EDXRF), scanning electron microscopy-energy dispersive X-ray (SEM-EDX), density measurement by the Archimedes method, and metallographic analysis. The measurements by EDXRF and SEM-EDX showed that the pieces were composed mostly gold and silver. The XRD results indicated that the microstructure of the objects corresponded to a single phase of gold and silver. The images obtained by the metallographic microscope showed equiaxial grains with some twins, a structure consistent with annealed metals. The different colours observed correspond to different grain orientations. Pre-Hispanic objects from a second archaeological site in the municipality of Amalfi (Department of Antioquia) were also analysed for comparative purposes. The results showed that the gold objects were not subjected to any alloying process, but were instead manipulated in their original form (native gold). The shape of the objects and their microstructural results suggested that the pieces were manufactured by casting, mechanical deformation and then annealing.     

Dating and provenance of glass artefacts excavated from the ancient city of Tall Zirā‛a,Jordan

Fourteen glass objects recovered from excavations at the ancient city of Tall Zirā‛a, Jordan, were analysed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to determine the period and origin of manufacture. The composition of glasses manufactured in the Late Bronze Age (LBA) and Iron Age are distinctly different, therefore major element analysis can be used to distinguish between the groups relatively easily. The LA-ICP-MS analysis provided quantitative trace element data which were used to determine the provenance of those glasses identified as LBA. This research discusses the implications of the presence of both Egyptian and Mesopotamian LBA glasses and examines the varying compositions and colour strategies employed in both the LBA and Iron Age objects. Specifically, glass in the LBA was considered to be one of the highest status items attainable, playing an instrumental role in diplomatic gift-giving. When considered with the archaeological information, the significance of these finds at Tall Zirā‛a indicates that this city was a settlement of high status, not primarily a convenient trading stop on the Transjordan route.     

Nano-CT evaluation of totally corroded coins: A demonstration study to determine if detail might still be discernible despite the lack of internal,non-corroded,metal

Five unidentifiable, completely corroded ancient coins (three of which were large fragments), proven to lack any residual internal metal, were scanned by nano-computed tomography (CT) to see if discernible detail might still be present. One fragment could be identified as an early fourth-century Urbs Roma commemorative AE 3/4. Another fragment was a coin of either Valerian or of the joint rule of Valerian and Gallienus, which could be dated to the period 254–56 ce . The other three lacked discernible detail. This proof-of-concept study shows that nano-CT scanning has the potential to allow non-invasive identification of at least some totally corroded coins.     

Geological constraints on the use of lead isotopes for provenance in archaeometallurgy

The first part of this paper is a brief critical history of the use of Pb isotopes for inferring the geological provenance of archaeological materials, with an emphasis on non-ferrous metals. The second part examines variation in the Pb isotopic ratios of oxide and sulphide ore minerals in selected regions of the world, and relates these to the geological histories of ore formation in each region. This exercise shows that in regions where most ore deposits are of similar geological age—as in the Andes, Europe and the circum-Mediterranean—provenance analysis with Pb isotopes is inherently difficult because geographically distant sources often exhibit similar isotopic ratios. Conversely, regions with many periods of ore formation—such as southern Africa—appear to be very promising regions for future studies of provenance with Pb isotopes. The wider implication of this exploratory survey is that archaeologists should carefully consider the range and clustering of geological Pb isotopic ratios in their regions of interest before investing large sums of money into Pb isotopic analysis of artefacts.     

To what extent can online mapping be decolonial? A journey throughout Indigenous cartography in Canada

In this paper, we describe and reflect upon our journey through Indigenous online mapping in Canada. This journey has been planned according to an academic goal: assessing the potential of online cartography for decolonial purposes. To reach this goal, we have followed methodological directions provided by Indigenous scholar Linda Tuhiwai Smith to review 18 Indigenous web-mapping sites across Canada. Supported by a series of ten interviews, this content analysis enabled us to sketch some of the contours of contemporary Indigenous cartography. On one hand, Indigenous communities largely control the data that are shared on these websites. They also partially control the way these data are represented through the mobilization of digital storytelling technologies that are better aligned with Indigenous ways of envisioning relationships to places than conventional maps. On the other hand, they do not have much control over the technological aspects of these projects, for which they remain heavily dependent on non-Indigenous partners. Throughout this journey, we noticed that women's voices remained marginal in most of these mapping projects, but we also identified evidence supporting the idea that these voices are starting to play a vital role in the on-going effort of decolonizing mapping processes.     

Life under lockdown: Notes on Covid-19 in Silicon Valley

This article is a preliminary exploration of the effects of Covid-19 in Silicon Valley, one of three pandemic ‘hotspots’ on America’s west coast. In particular, it describes how the crisis has deepened and magnified social and economic inequalities in a region where poverty, homelessness and gentrification are rife. Despite the fact that many technology firms are reaping massive profits in the wake of ‘shelter in place’ orders, many Silicon Valley workers have lost their jobs and are struggling to cope with the consequences of Covid-19. The article also analyzes the different meanings of ‘lockdown’ by comparing examples from China, Brazil, Taiwan and the United States. The authors conclude that anthropologists have a significant role to play in helping to understand how and why communicable diseases emerge, the underlying social and environmental conditions that fuel them and cross-cultural strategies for the effective mitigation of epidemics and pandemics.