Silver isotope and volatile trace element systematics in galena samples from the Iberian Peninsula and the quest for silver sources of Roman coinage

Silver played a key role in the progressive monetization of early Mediterranean civilizations. We combine Pb and Ag isotopes with volatile trace elements (Bi, Sb, and As) to assess whether, during the Roman occupation of Iberia, galena constituted a significant source of silver. We find that the Pb and Ag isotopic compositions of 47 samples of galena from eight different Iberian mining provinces, many of them exploited during Roman times, are uncorrelated. This indicates that their respective isotopic variabilities depend on different petrogenetic processes. Moreover, the range of Ag isotopic abundances is approximately six times wider than that displayed worldwide by silver coins in general and Roman silver coins in particular. Although galena from the Betics provides the best fit for Pb isotopes with Roman coins, their fit with Ag isotopic compositions is at best sporadic. We suggest that, together with Sb, Bi, and As, silver is primarily derived from fluids boiled off from differentiated mantle-derived magmas. These fluids, in turn, reacted with preexisting galena and functioned as a silver trap. Lead sulfides with ε109Ag of ~0 and unusually rich in Ag, Sb, Bi, and As were the most probable sources of ancient silver, whereas samples with ε109Ag departing significantly from ~0 reflect low-temperature isotopic fractionation processes in the upper crust.

Standard Atomic Weight of Lead Revised

Following the recent publication of the IUPAC Technical Report on the variation of lead isotopic composition and atomic weight in terrestrial materials [1], the IUPAC Commission on Isotopic Abundances and Atomic Weights (CIAAW) is recommending changes to the standard atomic weight (i.e. relative atomic mass) of lead:

Supplemental Material: 40Ar/39Ar age evidence for an impact-generated hydrothermal system in the Devonian Siljan crater, Sweden

Supplemental Material 1: Item S1 (additional information on ⁴⁰Ar/³⁹Ar age spectra of biotite), and Item S2 (additional information on ⁴⁰Ar/³⁹Ar age spectra of amphibole); and Supplemental Material 2: Tables S1–S4 (Ar isotopic ratios, apparent ages, J values, Ar isotopic abundances, and Ca/K and Cl/K ratios). <br>

Supplemental Material: 40Ar/39Ar age evidence for an impact-generated hydrothermal system in the Devonian Siljan crater, Sweden

Supplemental Material 1: Item S1 (additional information on ⁴⁰Ar/³⁹Ar age spectra of biotite), and Item S2 (additional information on ⁴⁰Ar/³⁹Ar age spectra of amphibole); and Supplemental Material 2: Tables S1–S4 (Ar isotopic ratios, apparent ages, J values, Ar isotopic abundances, and Ca/K and Cl/K ratios). <br>

Hazelnut products traceability through Isotope Ratio Mass Spectrometry approach

&lt;p&gt;The geographical origin of hazelnuts products is nowadays a relevant aspect of high-quality food characterization. Isotope Ratio Mass Spectrometry (IRMS) could play a key role in origin discrimination. The present study aims to assess the geographical provenience of Italian roasted hazelnuts and paste of hazelnuts, by analysing relative isotopic ratios of carbon, nitrogen, and oxygen, through Elemental Analyzer &amp;#8211; and Thermal Conversion &amp;#8211; Isotope Ratio Mass Spectrometry. Method development is performed by evaluating test samples repeatability, considering 15 replicates measurements on the same day, reproducibility, considering 30 replicates measurements on two different days, and robustness, considering 30 replicates measurements, varying mass parameter. Preliminary outcomes highlight reproducible and robust results, having acceptable standard deviation values (from 0.07 to 0.3). One-way ANOVA test demonstrates a significant statistical difference between Italian and Georgian hazelnut test samples (ca. 1 &amp;#948; of difference). A Design of Experiment, for training and validation sets building, is prepared, taking into account factors as harvesting year, variety, processing, and percentage of the peel. A total of n=30 processed hazelnuts lots, from Italy, Turkey, Georgia, and Azerbaijan, are going to be analysed for origin evaluation. Despite further analysis are still in progress, this strategy could potentially be the election method for a lot of food chain traceability since food isotopic abundances reflect ground and climate-related features, typical of precise locations. Moreover, this approach consists of limited or even inexistent sample preparation and provides for high sensitivity.&lt;/p&gt;

Measuring the fine structure constant on a white dwarf surface; a detailed analysis of Fe V absorption in G191-B2B

The gravitational potential φ = GM/Rc2 at the surface of the white dwarf G191-B2B is 10,000 times stronger than that at the Earth’s surface. Numerous photospheric absorption features are detected, making this a suitable environment to test theories in which the fundamental constants depend on gravity. We have measured the fine structure constant, α, at the white dwarf surface, used a newly calibrated Hubble Space Telescope STIS spectrum of G191-B2B, two new independent sets of laboratory Fe V wavelengths, and new atomic calculations of the sensitivity parameters that quantify Fe V wavelength dependency on α. The two results obtained are: Δα/α0 = (6.36 ± 0.35stat ± 1.84sys) × 10−5 and Δα/α0 = (4.21 ± 0.48stat ± 2.25sys) × 10−5. The measurements hint that the fine structure constant increases slightly in the presence of strong gravitational fields. A comprehensive search for systematic errors is summarised, including possible effects from line misidentifications, line blending, stratification of the white dwarf atmosphere, the quadratic Zeeman effect and electric field effects, photospheric velocity flows, long-range wavelength distortions in the HST spectrum, and variations in the relative Fe isotopic abundances. None fully account for the observed deviation but the systematic uncertainties are heavily dominated by laboratory wavelength measurement precision.

Analysis of the TiO isotopologues in stellar optical spectra

Context. We used the new ExoMol TiO rovibronic line lists to identify and model TiO isotopologue features in spectra of M dwarfs. Aims. We investigate problems involving the computation of electronic bands for different isotopologues of TiO by modelling optical spectra of late-type stars. Based on this, we determine their Ti isotopic abundances and compare the TiO isotopologue spectra computed using line lists by different authors. Methods. We fitted theoretical synthetic spectra to the observed stellar molecular bands of TiO. We modelled spectra of two M dwarfs, GJ 15A (M1V) and GJ 15B (M3 V), to determine Ti isotopic ratios in their atmospheres. Results. We demonstrate the accuracy of the ExoMol TOTO line list for different isotopologues of TiO and the possibility of determining accurate Ti isotope abundances in a number of spectral ranges. The 7580–7594 Å spectral range seems particularly useful, with two atomic lines of Fe I and molecular band heads of 50Ti O, 49Ti O, 48Ti O, and 47Ti O clearly observable in our two M-dwarf spectra. We determine non-solar Ti isotopic ratios of 46Ti, 47Ti, 48Ti, 49Ti, and 50Ti of 7.9, 5.2, 72.8, 7.9, and 6.2 for GJ 15A and 7.4, 4.2, 76.6, 5.8, and 6.0 for GJ 15B with an accuracy of ±0.2. [Ti] = 0.040 and 0.199 and within an accuracy of ±0.10 were also determined for GJ 15A and GJ 15B, respectively. Conclusions. We find that the ExoMol TOTO TiO line list (a) describes the fine details in line position and intensity of the M-dwarf spectra better than other available TiO line lists, (b) correctly reproduces the positions and intensities of the TiO isotopologue band heads observed in M-dwarf spectra, and (c) can be used to determine Ti isotope abundances in atmospheres of M stars.

The universal sample holders of microanalytical instruments of FIB, TEM, NanoSIMS, and STXM-NEXAFS for the coordinated analysis of extraterrestrial materials

We developed universal sample holders [the Kochi grid, Kochi clamp, and Okazaki cell) and a transfer vessel (facility-to-facility transfer container (FFTC)] to analyze sensitive and fragile samples, such as extremely small extraterrestrial materials. The holders and container prevent degradation, contamination due to the terrestrial atmosphere (water vapor and oxygen gas) and small particles, as well as mechanical sample damage. The FFTC can isolate the samples from the effects of the atmosphere for more than a week. The Kochi grid and clamp were made for a coordinated micro/nano-analysis that utilizes a focused-ion beam apparatus, transmission electron microscope, and nanoscale secondary ion mass spectrometry. The Okazaki cell was developed as an additional attachment for a scanning transmission X-ray microscope that uses near-edge X-ray absorption fine structure (NEXAFS). These new apparatuses help to minimize possible alterations from the exposure of the samples to air. The coordinated analysis involving these holders was successfully carried out without any sample damage or loss, thereby enabling us to obtain sufficient analytical datasets of textures, crystallography, elemental/isotopic abundances, and molecular functional groups for µm-sized minerals and organics in both the Antarctic micrometeorite and a carbonaceous chondrite. We will apply the coordinated analysis to acquire the complex characteristics in samples obtained by the future spacecraft sample return mission.