Estimating global fluxes of precious metals is key to understanding early monetary systems. This work adds silver (Ag) to the metals (Pb and Cu) used so far to trace the provenance of coinage through variations in isotopic abundances. Silver, copper, and lead isotopes were measured in 91 coins from the East Mediterranean Antiquity and Roman world, medieval western Europe, 16th–18th century Spain, Mexico, and the Andes and show a great potential for provenance studies. Pre-1492 European silver can be distinguished from Mexican and Andean metal. European silver dominated Spanish coinage until Philip III, but had, 80 y later after the reign of Philip V, been flushed from the monetary mass and replaced by Mexican silver.

Natural isotopic variations of metals in human blood and tissues turn out to be potent biomarkers of pathologies.

We describe a chemical separation protocol of calcium from biological materials for isotopic measurement by multiple collector inductively coupled plasma mass spectrometry (MC-ICPMS). The method was tested using elution profiles along with HCl and HNO₃ acids only, on human urine, sheep serum and red blood cells (RBC), seawater and herbaceous plants. It allows the elimination of all interfering species (including K, Sr, Mg) and the remaining matrix (including Fe, P, Na and S) beyond required levels. In order to further test this protocol and better understand the Ca isotopic signatures of mammalian fluids and organs, we purified and analyzed a wide range of materials from sheep, i.e. serum, RBC, muscle, liver, kidneys, enamel, bone, urine and feces. The data show a wide range of variations, expressed as δ, over 1‰ per amu, with a precision of 0.1‰ or better, spanning most of the variability reported so far. Red blood cells appeared to be heavier than serum by 0.3‰ per amu. This isotopic difference between serum and red blood cells was not taken into account in previous studies and it provides further information on Ca isotopic cycling in organisms. The Ca isotopic compositions of organs are correlated with concentrations, bone and RBC representing the two end-members, bone being Ca rich and ⁴⁴Ca-depleted and RBC Ca poor and ⁴⁴Ca-enriched. The trend is compatible with a distillation process by which Ca is extruded from cells along with a kinetic fractionation process favoring lighter Ca isotopes.

High quality records of stratospheric volcanic eruptions, required to model past climate variability, have been constructed by identifying synchronous (bipolar) volcanic sulfate horizons in Greenland and Antarctic ice cores. Here we present a new 2600-year chronology of stratospheric volcanic events using an independent approach that relies on isotopic signatures (Δ³³S and in some cases Δ¹⁷O) of ice core sulfate from five closely-located ice cores from Dome C, Antarctica. The Dome C stratospheric reconstruction provides independent validation of prior reconstructions. The isotopic approach documents several high-latitude stratospheric events that are not bipolar, but climatically-relevant, and diverges deeper in the record revealing tropospheric signals for some previously assigned bipolar events. Our record also displays a collapse of the Δ¹⁷O anomaly of sulfate for the largest volcanic eruptions, showing a further change in atmospheric chemistry induced by large emissions. Thus, the refinement added by considering both isotopic and bipolar correlation methods provides additional levels of insight for climate-volcano connections and improves ice core volcanic reconstructions.

This work addresses the issue of how isotope mass biases in modern Multiple-Collector Inductively Coupled Plasma Mass Spectrometers (MC-ICP-MS) changes with increasing efficiency of ion transfer through the instrument, which is known as transmission (τ). For any element, when all the ions introduced into the source are accounted for at the collector, the instrumental mass bias must vanish. With the latest cone designs, such as Thermo Finnigan jet cones, transmissions in excess of 2 percent are now obtained for heavy elements and coincide with smaller values of instrumental isotope fractionation factors. Transmission of ions across the entire mass range has been measured on a Thermo Neptune Plus equipped with standard and jet cones. It was found that transmission τ of elements above mass 40 increases linearly with the atomic weight. Comparing this relationship with the well-established linear dependence of ion energy with atomic mass indicates that high transmission is intimately related to the thermodynamic reversibility of the gas flow in the interface. Instrumental isotope fractionation obeys an exponential law with β as a coefficient. Instrumental isotopic fractionation is due to the transverse spread of the beam inherited from Ar thermal movements at the high temperatures of the plasma. It was found that, for τ > 0.002, the exponential law coefficient β ≈ −0.24 ± 0.02 ln τ in contrast to β ≈ 2 at lower transmission. The exponential mass fractionation coefficient can be approximated by the following law: β = β₀ (1 − τ^γ).