Otoliths as indicators for fish behaviour and procurement strategies of hunter-gatherers in north Patagonia

This study evaluates the potential use of archaeological otoliths of Genidens barbus (Cuvier and Valenciennes) as a tool to study fish behavior and hunter-gatherers procurement strategies on the North Patagonian coast. The studied samples come from the San Antonio archaeological locality dated at ca. 1000-800 14C yr BP (Late Holocene). To assess whether exposure to fire significantly affects the otolith Sr:Ca and Ba:Ca ratios, burned and unburned modern lapilli otoliths have been analyzed by Laser Ablation Inductively Coupled Plasma Mass Spectrometry and no statistically significant differences were found between the results of both treatments. Core-toedge chemical time series were carried out on ancient otoliths (ca. 1000 14C yr BP) in order to study the fish life history. Three amphidromous patterns were found for ancient samples. The capture environments and seasons inferred by the otolith edge chemistry and marginal increase, respectively, suggest a location in high salinity water (estuary and sea) in summer. Finally, to estimate the size of archaeological fish, a linear regression between total length and otolith length was constructed using 70 modern catfish otoliths. The size variability (358–610 mm) might indicate the use of non-selective capture techniques, probably nets, by hunter-gatherer groups.Fil: Avigliano, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; ArgentinaFil: Martinez, Gustavo Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano. Universidad Nacional del Centro de la Provincia de Buenos Aires. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano; ArgentinaFil: Stoessel, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano. Universidad Nacional del Centro de la Provincia de Buenos Aires. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano; ArgentinaFil: Méndez, Ana. Universidad de Oviedo; EspañaFil: Bordel, Nerea. Universidad de Oviedo; EspañaFil: Pisonero, Jorge. Universidad de Oviedo; EspañaFil: Volpedo, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; Argentin

Elucidation of the chemical role of the pyroclastic materials on the state of conservation of mural paintings from Pompeii

Pyroclastic strata have always been thought to protect the archaeological remains of the Vesuvian area (Italy), hence allowing their conservation throughout the centuries. In this work, we demonstrate that they constitute a potential threat for the conservation state of the mural paintings of Pompeii. The ions that could be leached from them and the ion‐rich groundwater coming from the volcanic soil/rocks may contribute to salt crystallisation. Thermodynamic modelling not only allowed to predict which salts can precipitate from such leaching events but also assisted the identification of additional sources of sulfates and alkali metals to explain the formation of the sulfates identified in efflorescences from the mural paintings of Pompeii. For the future, fluorine, mainly related to a volcanic origin, can be proposed as a marker to monitor the extent of the impact in the mural paintings of Pompeii in situ

Elucidation of the Chemical Role of the Pyroclastic Materials on the State of Conservation of Mural Paintings from Pompeii

Pyroclastic strata have always been thought to protect the archaeological remains of the Vesuvian area (Italy), hence allowing their conservation throughout the centuries. In this work, we demonstrate that they constitute a potential threat for the conservation state of the mural paintings of Pompeii. The ions that could be leached from them and the ion‐rich groundwater coming from the volcanic soil/rocks, may contribute to salt crystallisation. Thermodynamic modelling not only allowed to predict which salts can precipitate from such leaching events, but also assisted the identification of additional sources of sulfates and alkali metals, to explain the formation of the sulfates identified in efflorescences from the mural paintings of Pompeii. For the future, fluorine, mainly related to a volcanic origin, can be proposed as a marker to monitor in situ the extent of the impact in the mural paintings of Pompeii.The research leading to these results has received funding from “la Caixa” Foundation (Silvia Pérez-Diez, ID 100010434, Fellowship code LCF/BQ/ES18/11670017). This work has been supported by the projects MADyLIN (Ministry of Economy, Industry and Competitiveness from Spain, Grant No. BIA2017‐87063‐P) funded by the Spanish Agency for Research AEI (MINECO-FEDER/UE) and MINECO-17-CTQ2016-77887-C2-1-R

Chemometrics and elemental mapping by portable LIBS to identify the impact of volcanogenic and non-volcanogenic degradation sources on the mural paintings of Pompeii

Crystallization of soluble salts is a common degradation phenomenon that threatens the mural paintings of Pompeii. There are many elements that contribute to the crystallization of salts on the walls of this archaeological site. Notably, the leachates of the pyroclastic materials ejected in 79 AD by Mount Vesuvius and local groundwater, rich in ions from the erosion of volcanic rocks. Both sources could contribute to increase the concentration of halides (fluorides and chlorides) and other salts in these walls. The distribution of volcanogenic salts and their impact on the conservation of Pompeian mural paintings have however not yet been fully disclosed. In this work, an analytical methodology useful to determine the impact of the main sources of degradation affecting the mural paintings of Pompeii is presented. This methodology combines the creation of qualitative distribution maps of the halogens (CaF and CaCl) and related alkali metals (Na and K) by portable Laser Induced Breakdown Spectroscopy (LIBS) and a subsequent Principal Component Analysis of these data. Such maps, together with the in-situ identification of sulfate salts by portable Raman spectroscopy, provided information about the migration and distribution of volcanogenic halides and the influence of ions coming from additional sources (marine aerosol and modern consolidation mortars). Additionally, the thermodynamic modeling developed using the experimentally determined ionic content of Pompeian rain- and groundwater allowed to determine their specific role in the formation of soluble salts in the mural paintings of Pompeii.The research leading to these results has received funding from “la Caixa” Foundation (Silvia P erez-Diez, ID 100010434, Fellowship code LCF/BQ/ES18/11670017). This work has been supported by the Spanish Agency for Research AEI (MINECO- FEDER /UE) through the projects MADyLIN (BIA2017-87063-P) and MINECO-17-CTQ2016-77887-C2-1-R, and the Government of the Principality of Asturias (GRUPIN IDI/2018/000186). The authors thank for technical and human support provided by the laboratory Raman-LASPEA of SGIker (UPV/EHU/ ERDF, EU)

Comparison of Mg/Ca concentration series from Patella depressa limpet shells using CF-LIBS and LA-ICP-MS

The elemental composition of marine mollusk shells can offer valuable information about environmental conditions experienced by a mollusk during its lifespan. Previous studies have shown significant correlations between Mg/Ca concentration ratios measured on biogenic carbonate of mollusk shells and sea surface temperature (SST). Here we propose the use of Laser-Induced Breakdown Spectroscopy (LIBS) and the validation of the Calibration-Free LIBS (CF-LIBS) approach for the rapid measurement and estimation of Mg/Ca molar concentration profiles within Patella depressa Pennant, 1777 limpet shells. To achieve these objectives, results derived from CF-LIBS methodology are compared with those obtained from an established analytical technique for this purpose, such as Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). Concentration series obtained with both methodologies show defined temporal patterns and reflect the season-of-capture in each specimen. The results evidence a significant correlation (R2 = 0.63–0.81) between CF-LIBS and LA-ICP-MS Mg/Ca molar concentration profiles within four live-collected P. depressa shells. Averaged error for the molar concentration estimated with CF-LIBS was lower than 10% in every specimen. The comparison between the results obtained from two techniques used in this study has allowed us to demonstrate for the first time that Mg/Ca molar concentration measured in biogenic carbonates were accurately inferred using CF-LIBS technique. The CF-LIBS approach validation represents great potential for the rapid and large-scale paleoenvironmental and archaeological analysis of this mollusk species, which is frequently found in archaeological sites.1. Introduction 2. Materials and methods 2.1. Sample preparation 2.2. LA-ICP-MS setup and analyses 2.3. LIBS setup and measurements 2.4. CF-LIBS application 3. Results and discussion 3.1. LA-ICP-MS concentration profiles 3.2. CF-LIBS approach results 3.3. CF-LIBS and LA-ICP-MS comparison 3.4. Implications for paleoclimatology and archaeology 4. Conclusion

Mixed-stock and discriminant models use for assessing recruitment sources of estuarine fish populations in la Plata Basin (South America)

The objective of this study was to identify potential recruitment sources of Prochilodus lineatus from freshwater areas (Paraná and Uruguay rivers) to estuarine population of the Río de la Plata Estuary (La Plata Basin, South America), considering young (age-1) and adult (age-7) fish. LA-ICP-MS chemical analysis of the otolith core (nine element:Ca ratios) of an unknown mixed sample from Río de la Plata Estuary (2011 and 2017) was compared with a young-of-year baseline data set (same cohort) and classified into freshwater nurseries (Paraná or Uruguay river) by using maximum classification-likelihood models (MLE and MCL) and quadratic discriminant analysis (QDA). Considering the three models used, the Uruguay River was the most important contributor for both young and adult populations. The young population (2011) was highly mixed with contributions between 31.7 to 68.3%, while the degree of mixing was found to decrease in 2017 (adult fish) from 97.1 to 100% contributions. The three employed methods showed comparable estimates, however, the QDA showed a high similarity with the MCL model, suggesting sensitivity to evaluate small contributions, unlike the MLE method. Our results show the potential application of maximum likelihood mixture models and QDA for determining the relative importance of recruitment sources of fish in estuarine waters of the La Plata Basin.Fil: Avigliano, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; ArgentinaFil: Pisonero, Jorge. Universidad de Oviedo; EspañaFil: Bordel, Nerea. Universidad de Oviedo; EspañaFil: Dománico, Alejandro. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Volpedo, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; Argentin