One,two, three phytoliths: assessing the minimum phytolith sum for archaeological studies

The number of phytolith studies has increased steadily in the last decades in palaeoecological as well as archaeological research, and phytolith analysis is currently recognised as a proper area of expertise within archaeobotany. This has led towards a strengthening in the standardisation of the different steps involved in analysis; e.g. sampling strategies, laboratory extraction or processing of plant material/soils for the creation of reference collections. In spite of this, counting procedures remain one of the areas that could be further developed. The aim of this paper is to assess representativeness of phytolith count size in archaeological samples and specifically to assess whether an increase in total number of individuals counted influences the number or distribution of morphotypes observed. Two statistical tests are performed to evaluate the representativeness of count size: phytolith sum variability analysis (PSVA) and morphotype accumulation curve (MAC). The analyses show the relationship among the number of counted phytoliths, the variability (that is, the number of different morphotypes identified) and the stabilisations of the MACs. Results allow us to support the standard count size in phytolith studies, which ranges from 250 to 300 particles. Together with a quick scan, this strategy should produce a precise and clear phytolith assemblage for archaeological studies.     

The measurement of taxonomic evenness in zooarchaeology

Zooarchaeologists frequently measure taxonomic evenness to document subsistence change and to understand the response of faunal communities to paleoenvironmental change. Although the measurement of evenness is commonplace, there are numerous challenges involved. Evenness indices are sensitive to changing richness, and by extension sample size, and various indices respond differently to changing taxonomic abundances (i.e., changing evenness). To refine protocol for comparing assemblages of varied sampling effort and identify indices that may be more useful for zooarchaeological applications, we examine the quantitative behavior of the widely used Shannon evenness and Simpson indices and two others more commonly used by ecologists. These indices are examined in relation to varied richness, sample size, and taxonomic abundances. We show that although zooarchaeologists are concerned with identifying and correcting for the effects of sample size on evenness, it may be appropriate to instead focus on how richness modulates evenness. Based on our analyses, we recommend the Simpson index for most zooarchaeological applications, except when comparing evenness across assemblages that are very even.     

A geometric morphometric relationship predicts stone flake shape and size variability

The archaeological record represents a window onto the complex relationship between stone artefact variance and hominin behaviour. Differences in the shapes and sizes of stone flakes—the most abundant remains of past behaviours for much of human evolutionary history—may be underpinned by variation in a range of different environmental and behavioural factors. Controlled flake production experiments have drawn inferences between flake platform preparation behaviours, which have thus far been approximated by linear measurements, and different aspects of overall stone flake variability (Dibble and Rezek J Archaeol Sci 36:1945–1954, 2009; Lin et al. Am Antiq 724–745, 2013; Magnani et al. J Archaeol Sci 46:37–49, 2014; Rezek et al. J Archaeol Sci 38:1346–1359, 2011). However, when the results are applied to archaeological assemblages, there remains a substantial amount of unexplained variability. It is unclear whether this disparity between explanatory models and archaeological data is a result of measurement error on certain key variables, whether traditional analyses are somehow a general limiting factor, or whether there are additional flake shape and size drivers that remain unaccounted for. To try and circumvent these issues, here, we describe a shape analysis approach to assessing stone flake variability including a newly developed three-dimensional geometric morphometric method (‘3DGM’). We use 3DGM to demonstrate that a relationship between platform and flake body governs flake shape and size variability. Contingently, we show that by using this 3DGM approach, we can use flake platform attributes to both (1) make fairly accurate stone flake size predictions and (2) make relatively detailed predictions of stone flake shape. Whether conscious or instinctive, an understanding of this geometric relationship would have been critical to past knappers effectively controlling the production of desired stone flakes. However, despite being able to holistically and accurately incorporate three-dimensional flake variance into our analyses, the behavioural drivers of this variance remain elusive.     

Timber economy in the Roman Age: charcoal data from the key site of Herculaneum (Naples,Italy)

The city of Herculaneum (Naples, southern Italy), buried by the volcanic eruption of Mount Somma-Vesuvius in 79 ad, is a key site for understanding the timber economy during the Roman period. In this paper, the results of charcoal analysis of different building element types are presented. Beams, joists, poles, planks and door and window frames were investigated allowing us a view of which timber the Romans preferred for building in this area. We also fit the taxonomic results into the reconstruction of the ancient Campanian landscape, and finally, we discuss the knowledge that the Romans had about the technological properties of the wood that they used for building and the possible selection criteria that they followed in choosing them. Coniferous timber is the preferred material for building purposes. Abies alba is especially used, this fact confirming its stronger presence in southern Italian woods during the past and suggesting that its decline is mainly due to human overexploitation. The large presence of Cupressus sempervirens, selectively used for the production of poles, confirms that this tree was cultivated in plantations for timber production in the Vesuvius area. Furthermore, it might indicate that cypress could have been present as a natural tree in the local vegetation, suggesting a forest type that nowadays almost completely disappeared from this area and from the entire Italy. The findings of Juglans regia, Pinus pinea and Olea europaea, typical elements of the Mediterranean cultural landscape, show that their use was not limited to fruit production and that Romans also appreciated their timber. Beside these local resources, the presence of Picea abies and Picea/Larix indicates the importation of timber from northerly regions, probably the northern Apennines and the Alps.     

Non-destructive spectroscopic investigation of artefacts from middle Hallstatt period—case study of a stone bead from Tărtăria I hoard,Romania

A stone bead, part of a necklace found in a middle Hallstatt period—type of settlement—the T?rt?ria site in Alba County, Romania, was investigated following a non-destructive approach, by means of energy-dispersive X-ray fluorescence spectrometry and Fourier transform infrared spectroscopy. The highly heterogenous object, found together with numerous bronze and iron objects, appeared to be a variety of chalcedony rich in iron and copper impurities, still preserving clay minerals from the sedimentary matrix in some of the areas. Organic molecules found at the surface of the stone artefact may indicate the presence of a wax or resin residue, possible evidence of early craft specialization. The non-destructive protocol applied allowed an in-depth characterization of the artefact, providing important information not only on the crystal structure but also on the diagnostic impurities present within this peculiar stone bead.     

An empirical evaluation of copper procurement and distribution: elemental analysis of Scioto Valley Hopewell copper

In prehistoric North America, artifacts of copper occupy a position of prominence in the Hopewell societies of Ohio’s Scioto Valley. These artifacts also represent the social contacts and long-distance interactions that brought copper to the Scioto Valley. Yet, our understanding of Hopewell copper acquisition, and the movement of copper artifacts within the social networks of the Scioto Valley and beyond, has been limited due to the limited availability of geochemical data concerning provenance and variability. We begin to develop the foundation for understanding these important social issues by analyzing the elemental variability of Hopewell copper through the use of laser ablation inductively coupled plasma mass spectrometry. We analyze 24 samples from four known copper source regions and 52 samples from 6 prominent sites in the Scioto Valley. Results suggest that a majority of the artifacts are consistent with sources in the Great Lakes, with a plurality classified as Isle Royale. However, 21% of Scioto Hopewell copper artifacts were most consistent with southern Appalachian sources. High elemental variability argues against simple models of copper acquisition and suggests that different social groups had access to a variety of copper sources through varying social networks. Native copper regardless of source seems to have been channeled along similar social and symbolic pathways. Our results suggest that instead of being derived from the struggle to access a specific source, value is derived from the social relationships represented by the copper and the connotation of exotic connection embodied in both style and material.     

Dental and oral nonmetric traits in a Coimbra reference sample: testing intrasample chronological and spatial variation

A reference sample of dental and oral nonmetric traits should represent its biological population from which it stems. The presence of individuals born at different times, different regions, and separate countries in the Coimbra-identified cranial collections provides the test of whether this sample reflects the biological continuity of this Portuguese sample among the late modern (early industrialization, nineteenth century) to early contemporary (early demographic transition, first half of the twentieth century) population of this region of central Portugal. The Coimbra collections were scored for 61 traits using methodology by Hauser and De Stefano (1989), Turner et al. (1991), Scott and Turner (1997), Irish (1998), and Marado and Silva (2016). The 600 individuals in the sample were divided by generation, region, and nationality. Their phenetic diversity was tested with principal component analysis and with the mean measure of divergence statistic. The proximity between the subsamples was generalized, and it mimicked previous genetic marker results. Some small subsamples hindered conclusions; nevertheless, this Coimbra sample is considered a reliable dental reference sample for the Portuguese late modern/early contemporary population.     

Metallurgical study on some Sasanian silver coins in Sistan Museum

Elemental analyses and microstructural studies of historical metal artifacts provide researchers with invaluable and priceless information about metal extraction technology and the procedure of creating artifacts. In addition, the information is helpful for knowing about the metallurgical processes of the artifacts. This study was conducted by a microscopic examination and elemental analyses of seven Sasanian silver coins preserved in the Sistan Anthropology Museum, Iran. For the purpose of this study, three methods were employed: first, the proton induced X-ray emission microanalysis (micro-PIXE), to determine the main and trace elements of the coins; second, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), to perform elemental analysis to identify impurities of the metal; and third, microstructural analysis of the coins which was carried out with an optical microscope (OM). The elemental analyses identified Ca, Cu, Ag, Au, and Pb in the coins. The high quantity of Ag in samples validated the application of advanced and accurate cupellation technology for refining silver and separating impurities from raw ore. The gold concentration in the coins indicated the use of non-galena ore for silver extraction. Additionally, the microstructural analyses of samples pointed to the application of thermo-mechanical processes on coins.     

Characterization of concrete from Roman buildings for public spectacles in <Emphasis Type="Italic">Emerita Augusta</Emphasis> (Mérida,Spain)

The aim of this work is to characterize the original concrete from Roman buildings for public spectacles, theatre and amphitheatre, from Emerita Augusta, Mérida, Spain. An advanced knowledge of the Roman concrete composition is required for a reliable restoration and preservation of these ancient monuments. The concrete was studied through mineralogical (optical polarized microscopy and X-ray diffraction) and petrophysical (bulk and real density, open porosity to water and Hg, mechanical strength and ultrasonic velocity) analyses. With this work, it is possible to fill the gap that exists in this field and the characterization of the materials used in the Roman concrete from these two buildings, never previously studied, despite the significance of this archaeological ensemble, declared a World Heritage Site by UNESCO in 1993. The results allowed us to determine the composition of the Roman concrete and to infer the provenance of the aggregates used in these monuments.