Detailed analysis of the lamination and the geochemical varibility of the speleothem Zerolin to study the paleoclimate of SE Spain

This work reports an exhaustive analysis of geochemistry and lamination in the paleoclimate study of Málaga using an actively stalagmite called Zerolín, collected in 2007 in the Cave of Ardales. U-Th dates indicate that the speleothem began forming 1000 years ago. The older portion of the stalagmite presents a very marked lamination with an alternation of white and porous layers and denser dark layers. Lamination is absent in the younger portion of the stalagmite, which features darker calcite and slower growth rates. In the laminated part of the speleothem, a comparison of layer counting and U/Th dates indicates that light and dark couplets are annual. A detailed age model was then produced for the laminated part of the stalagmite based on layer counting anchored to a precise U/Th age. For the non-laminated portion of the stalagmite, U/Th dates were used in Bchron software to produce an age model. Periods of higher growth rate coincide with a greater thickness of white layers. In nonlaminated sections, U/Th dates confirm important depositional gaps. In the geochemical analysis it was discovered that the relationship and behavior of trace elements and stable isotopes is different in the upper zone than in the lower annually laminated zone. Over annual laminae cycles, trace elements such as Sr and d13C covary and may be driven by prior calcite precipitation, however Mg is out of phase with Sr. In nonlaminated segments, the correlations are not as systematic. The trace element and d13C indicate two periods of drier conditions in the stalagmite (1100-1200/1600-1800 AD) .These coincide with periods when there was an increase in the frequency of prayers for rainfall in historical documents from the Toledo Cathedral (F.Dominguez Castro et.al 2008), suggesting that the stalagmite is reflecting regionally significant humidity changes.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Laser ablation inductively coupled plasma mass spectrometry for direct analysis of the spatial distribution of trace elements in metallurgical-grade silicon

The spatial distribution and concentration of impurities in metallurgical-grade silicon (MG-Si) samples (97-99% w/w Si) were investigated by use of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The spatial resolution (120μm) and low limits of detection (mg kg−1) for quality assurance of such materials were studied in detail. The volume-dependent precision and accuracy of non-matrix-matched calibration for quantification of minor elements, using NIST SRM 610 (silicate standard), indicates that LA-ICP-MS is well suited to rapid process control of such materials. Quantitative results from LA-ICP-MS were compared with previously reported literature data obtained by use of ICP-OES and rf-GD-OES. In particular, the distribution of element impurities and their relationship to their different segregation coefficients in silicon is demonstrate

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

Atomic spectrometry update: review of advances in atomic spectrometry and related techniques

This review covers developments in ‘Atomic Spectrometry’. It covers atomic emission, absorption, fluorescence and mass spectrometry, but excludes material on speciation and coupled techniques which is included in a separate review. It should be read in conjunction with the previous review1 and the other related reviews in the series.2–6 A critical approach to the selection of material has been adopted, with only novel developments in instrumentation, techniques and methodology being included. One of the major developments which has gained traction over the past few years is the use of elemental tagging for the relative and absolute quantification of biological molecules using ICP-MS. This has advanced to the stage where it is now routinely used as an assay technique. A number of variations on this approach have also been developed in order to improve sensitivity by amplification of the signal, particularly for polynucleotide analysis. Single particle analysis by ICP-MS and ICP-AES has been used to gain some valuable insights into the atomisation and ionisation processes occurring in the ICP, as well as providing a means of quantification of nanoparticles. The dielectric barrier discharge (DBD) has attracted interest as a compact, low-power, microplasma source for MS and AES, following the trend for all things miniature, as well as for direct analysis of liquids. The use of MC-ICP-MS is the driver behind advances in the isotope ratio analysis of natural stable isotopes of metallic elements. Double spiking is an expanding method to neutralise instrumental and procedural mass-dependent fractionation in both stable and radiogenic isotope systems. An overlap is emerging between the measurement of uranium isotope variation in natural systems and the U isotope determination for the nuclear forensic or monitoring/safeguarding fields. Coincident analytical techniques between these fields is likely to produce useful advances in the analysis of nuclear materials

B content and Si/C ratios from cultured diatoms (Thalassiosira pseudonana and Thalassiosira weissflogii): Relationship to seawater pH and diatom carbon acquisition

AbstractDespite the importance of diatoms in regulating climate and the existence of large opal-containing sediments in key air-ocean exchange areas, most geochemical proxy records are based on carbonates. Among them, Boron (B) content and isotopic composition have been widely used to reconstruct pH from foraminifera and coral fossils. We assessed the possibility of a pH/CO2 seawater concentration control on B content in diatom opal to determine whether or not frustule B concentrations could be used as a pH proxy or to clarify algae physiological responses to acidifying pH. We cultured two well-studied diatom species, Thalassiosira pseudonana and Thalassiosira weissflogii at varying pH conditions and determined Si and C quotas. Frustule B content was measured by both laser-ablation inductively coupled mass spectrometry (LA-ICPMS) and secondary ion mass spectrometry (SIMS/ion probe). For both species, frustules grown at higher pH have higher B contents and higher Si requirements per fixed C. If this trend is representative of diatom silicification in a future more acidic ocean, it could contribute to changes in the efficiency of diatom ballasting and C export, as well as changes in the contribution of diatoms relative to other phytoplankton groups in Si-limited regions. If B enters the cell through the same transporter employed for HCO3− uptake, an increased HCO3− requirement with decreasing CO2 concentrations (higher pH), and higher B(OH)4/HCO3− ratios would explain the observed increase in frustule B content with increasing pH. The mechanism of B transport from the site of uptake to the site of silica deposition is unknown, but may occur via silicon transport vesicles, in which B(OH)4− may be imported for B detoxification and/or as part of a pH regulation strategy either though Na-dependent B(OH)4−/Cl− antiport or B(OH)4−/H+ antiport. B deposition in the silica matrix may occur via substitution of a B(OH)4− for a negatively charged SiO− formed during silicification. With the current analytical precision, B content of frustules is unlikely to resolve ocean pH with a precision of paleoceanographic interest. However, if frustule B content was controlled mainly by HCO3− uptake for photosynthesis, which appears to show a threshold behavior, then measurements of B content might reveal the varying importance of active HCO3− acquisition mechanisms of diatoms in the past

Step heating thermography supported by machine learning and simulation for internal defect size measurement in additive manufacturing

A methodology based on step-heating thermography for predicting the length dimension of small defects in additive manufacturing from temperature data measured on thermal images is proposed. Regression learners were applied with different configurations to predict the length of the defects. These algorithms were trained using large datasets generated with Finite Element Method simulations. The different predictive methods obtained were optimized using Bayesian inference. Using predictive methods generated and based on intrinsic performance results, knowing the material characteristics, the defect length can be predicted from single temperature data in defect and non-defect zone. Thus, the developed algorithms were implemented in a laboratory set-up carried out on ad-hoc manufactured parts of Nylon and polylactic acid which include induced defects with different sizes and thicknesses. Using the trained algorithm, the deviation of the predicted results for the defect size varied between 13% and 37% for PLA and between 13% and 36% for Nylon.This research has been funded by Ministry of Science and Innovation (Government of Spain) through the research project titled Fusion of nondestructive technologies and numerical simulation methods for the inspection and monitoring of joints in new materials and additive manufacturing processes (FaTIMA) with code RTI2018-099850-B-I00

Reconstrucción de la precipitación en el noroeste de la península ibérica durante los últimos 500 años usando un espeleotema de cueva fría, España

Ponencia presentada en: XXXV Jornadas Científicas de la AME y el XIX Encuentro Hispano Luso de Meteorología celebrado en León, del 5 al 7 de marzo de 2018.Aquí presentamos un registro de alta resolución de una estalagmita de una cueva ubicada en el centro de la Cordillera Cantábrica sin ninguna influencia antropogénica y sin variabilidad estacional de CO2. Esta estalagmita de 500 años, con una cronología elaborada con el método U / Th y con una tasa de crecimiento que varía entre 100 y 200 μm / año, calculada con el modelo Bchron, nos proporciona información precisa de las condiciones climáticas cercanas a la cueva a la que pertenece

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