Identifying a technological style in the making of lime plasters at Teopancazco (Teotihuacan,México)

The aim of this article is to focus on the technology of archeological plasters at Teotihuacan (Central Mexico), from the Classic Period (200–650 A.D.), focusing in the study of Teopancazco, a neighborhood center in the city. Petrographic and chemical analyses by OM, SEM-EDS, and LA-ICP-MS were conducted to characterize samples from different constructive phases and sectors of the neighborhood center, to determine the provenance of the raw materials employed in the manufacturing (e.g., volcanic glass shards) and to assess whether a shift occurred in the manufacturing of plasters and in the procurement strategies of raw materials during the different phases. The results of the analyses show that almost no changes occurred in the making of the plaster during more than four centuries and allow us to consider the presence of a technological style in their manufacture, which is characterized by the making of plaster by mixing lime with volcanic glass shards, which in the case of Teopancazco were derived from the Altotonga (Veracruz) magmatic system. The data at our disposal suggest that this style was developed in Teopancazco and later introduced throughout the city of Teotihuacan in the Early Xolalpan phase (A.D. 350), although we still do not know whether the provenance of the raw materials is the same. The wide distribution of this technological tradition could be due to the technological properties of the materials and/or the influence of the intermediate elite who ruled over Teopancazco. The paper confirms that the study of material culture and technology sheds light on broader cultural aspects of ancient societies.     

Archaeological Survey of the Ex-USS <Emphasis Type="Italic">Bugara</Emphasis> (SS/AGSS331)

In August 2017, a multidisciplinary team conducted the first archaeological survey of the deep water (242 m) wreck of the ex-USS Bugara (SS/AGSS331) using the remotely operated vehicles Argus and Hercules. The survey provided 8 h of direct observation with video and still camera documentation of the wreck, which previously had been identified by sonar and a brief ROV survey of portions of the hull in 2001. The 2017 assessment added considerably to an understanding of changes to Bugara after it sank while under tow in 1971. Bugara, a World War II-era submarine, served at the end of that conflict and through the Cold War. The submarine reflects a series of modifications to “modernize” it within the context of the Cold War. The examination of the wreck, along with additional archival research, offers more details not only on the probable cause of the sinking but also on subsequent site formation processes. The characterization of the wreck resulted in a reassessment of the site as more than an obsolete vessel accidentally lost when relegated to target practice. The archival record, now declassified, shows that Bugara’s loss also reflects its ultimate use, within the context of the Cold War, as a target for the Mark 48 torpedo, a newly developed “sub and ship killing” weapon designed in the late 1960s and tested through 1971 to take out Soviet deep-diving nuclear submarines and high-performance surface ships.     

Anthropogenic units fingerprinted by REE in archaeological stratigraphy: Mas d'Is (Spain) case

On occasions, archaeologists have to deal with serious difficulties to differentiate between processes that ultimately are responsible for the formation of stratigraphic units.Sometimes we face problems related with depositional units in multilayered deposits and other times, we ask for the character of some dark surface soils, very similar to natural paleosols and usually associated with archaeological findings. In both cases, the problems we must address concern the relative impact of human activities.The imbalance between anthropic and natural processes in the formation of archaeological deposits is crucial for a correct interpretation of the processes involved in the formation of archaeological sites, but also of their occupation-abandonment dynamics and the understanding of their spatial behaviors and relationship with the environment.In this paper we propose a new methodological approach for the identification of anthropogenic fingerprints in stratigraphic units through Rare Earth Elements (REE) soil analysis. The role of REE for the effective identification of sediment provenance due to their coherent behavior during weathering, erosion and fluvial transportation and their high resistance to chemical mobilization is well known in other areas of knowledge. We try to explore its potentiality in a challenging archaeological context. Our purpose was to identify human traces in stratigraphic units where archaeological materials are scarce or absent intertwined with others richer in archaeological remains by the determination of multiple elements and statistical studies. We believe that Rare Earth Elements (REE) soil analysis provides unique insights for a better characterization of natural and archaeological sediments but more importantly to recognize different stages of the gradient. We expect to discern between natural versus anthropic units and between primary versus secondary deposits (redeposition), using the case of the Neolithic site of Mas d'Is (Alicante, Spain) as an example. The application of the Principal Component Analysis (PCA) remarks differences in REE values, those analysis show differences between units of undoubtedly anthropogenic origin and control samples taken from natural sediments –including marls bedrock–, in their vicinity, but also we could notice finer nuances like the degree of human contributions to paleosols formation.     

Biological mineral content in Iberian skeletal cremains for control of diagenetic factors employing multivariate statistics

The aim of this study was to define a strategy for a correct selection of bone samples by employing inductively coupled plasma optical emission spectroscopy (ICP-OES) for reconstructing the biological mineral content in bones through the determination of major elements, trace elements and Rare Earth Elements (REE, lanthanides) in skeletal cremains of ancient Iberians (III–II B.C), discovered in the Necropolis of Corral de Saus (Moixent, Valencia) between 1972 and 1979. The biological mineral content was determined taking into account diagenetic factors. A control method for a better reading of results was applied. To explore large geochemical datasets and to reduce the number of variables, Principal Component Analysis (PCA) was used, thus, providing a deeper insight into the structure of the variance of the dataset. PCA shows that the elemental profiles of bone and soil samples are clearly different. Bone samples obtained from the outer bone layer were shown to have a different elemental composition; more similar to soil samples than samples of the inner bone layer. PCA scores and loadings plots were preferred to dendrograms obtained using Cluster Analysis, due to the limits of the latter one to appreciate the spatial ordering of samples. Partial least squares discriminant analysis (PLS-DA), a frequently used supervised classification method, was applied to differentiate between degradation states of bone samples. PLS-DA results obtained in this study confirmed that changes derived from different burning conditions were associated with transformations in the mineral part of the bones. Accordingly, carbonized bones can be differentiated from cremated bones. Class assignment of bone samples with uncertain thermal conditions in dependence on their elemental composition has shown to be feasible. Consequently, for biochemical-archaeological studies the analysis and statistical classification of carbonized and cremated archaeological bones, as well as those exposed to unknown thermal conditions together with experiments in modern bones, are recommended.     

The Study of Archaeological Floors: Methodological Proposal for the Analysis of Anthropogenic Residues by Spot Tests,ICP-OES,and GC-MS

The identification of chemical activity residues on archaeological surfaces requires the analysis of large numbers of samples, which can be costly and time consuming. Researchers wishing to apply sediment chemistry often are confronted with a dilemma of which technique to use and how to accommodate sediment chemistry into their budget. We propose an approach to the identification of chemical activity residues in which semiquantitative spot tests, which are cheap, quick, and easy to apply, are employed as an initial phase of analysis in order to leverage the results of more time-consuming and costly instrumental techniques. Three examples that pair spot tests with gas chromatography-mass spectroscopy and inductively coupled plasma-optical emission spectrometry analysis show that spot tests successfully identify areas of interest. This approach can save both time and research funds.     

Methods of Palaeodemography: The Case of the Iberian Oppida and Roman Cities in North‐East Spain

Ancient demography is a recurrent topic in archaeology, thanks to new methods and evidence from different surveys and excavations. However, different cultures or periods are studied on their own, without any comparison being made between them and of their population dynamics. The present paper seeks to advance the situation by defining methodologies to allow diachronic comparisons between two different periods and cultures. After setting out a methodological approach, the paper goes on to apply the same to a case study: namely the Roman conquest of north‐east Spain, comparing the demography of the ancient Iberian communities (fourth‐second centuries BCE) to the Roman colonization (first century BCE to first century CE). Roman urbanism is generally supposed to increase the population in a particular territory, but our present evidence refutes this point: a decrease in population is visible in urban or proto‐urban sites from the Iberian to Roman periods, though there is an increase in the rural densities.