Basaltic volcanism 'samples' the Earth's mantle to great depths, because solid-state convection transports deep material into the (shallow) melting region. The isotopic and trace-element chemistry of these basalts shows that the mantle contains several isotopically and chemically distinct components, which reflect its global evolution. This evolution is characterized by upper-mantle depletion of many trace elements, possible replenishment from the deeper, less depleted mantle, and the recycling of oceanic crust and lithosphere, but of only small amounts of continental material.

Mantle geochemistry: the message from oceanic volcanism

The Lu–Hf and Sm–Nd isotopic composition of CHUR: Constraints from unequilibrated chondrites and implications for the bulk composition of terrestrial planets

Preface.- Contributors.- List of Abbreviations.- Section 1: Basic Principles: Introduction.-Sources of Heavy Metals and Metalloids in Soils.- Chemistry of Heavy Metals and Metalloids in Soils.- Methods for the Determination of Heavy Metals and Metalloids in Soils.- Effects of Heavy Metals and Metalloids on Soil Organisms.- Soil-Plant Relationships of Heavy Metals and Metalloids.- Heavy Metals and Metalloids as Micronutrients for Plants and Animals.-Critical Loads of Heavy Metals for Soils.- Section 2: Key Heavy Metals And Metalloids: Arsenic.- Cadmium.- Chromium and Nickel.- Cobalt and Manganese.- Copper.-Lead.- Mercury.- Selenium.- Zinc.- Section 3: Other Heavy Metals And Metalloids Of Potential Environmental Significance: Antimony.- Barium.- Gold.- Molybdenum.- Silver.- Thallium.- Tin.- Tungsten.- Uranium.- Vanadium.- Glossary of Specialized Terms.- Index.

Heavy metals in soils : trace metals and metalloids in soils and their bioavailability

[1] We present an estimate for the composition of the depleted mantle (DM), the source for mid-ocean ridge basalts (MORBs). A combination of approaches is required to estimate the major and trace element abundances in DM. Absolute concentrations of few elements can be estimated directly, and the bulk of the estimates is derived using elemental ratios. The isotopic composition of MORB allows calculation of parent-daughter ratios. These estimates form the “backbone” of the abundances of the trace elements that make up the Coryell-Masuda diagram (spider diagram). The remaining elements of the Coryell-Masuda diagram are estimated through the composition of MORB. A third group of estimates is derived from the elemental and isotopic composition of peridotites. The major element composition is obtained by subtraction of a low-degree melt from a bulk silicate Earth (BSE) composition. The continental crust (CC) is thought to be complementary to the DM, and ratios that are chondritic in the CC are expected to also be chondritic in the DM. Thus some of the remaining elements are estimated using the composition of CC and chondrites. Volatile element and noble gas concentrations are estimated using constraints from the composition of MORBs and ocean island basalts (OIBs). Mass balance with BSE, CC, and DM indicates that CC and this estimate of the DM are not complementary reservoirs.

https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2003GC000597

Composition of the depleted mantle

We present new reference values for the NIST SRM 610–617 glasses following ISO guidelines and the International Association of Geoanalysts’ protocol. Uncertainties at the 95% confidence level (CL) have been determined for bulk- and micro-analytical purposes. In contrast to former compilation procedures, this approach delivers data that consider present-day requirements of data quality. New analytical data and the nearly complete data set of the GeoReM database were used for this study. Data quality was checked by the application of the Horwitz function and by a careful investigation of analytical procedures. We have determined quantitatively possible element inhomogeneities using different test portion masses of 1, 0.1 and 0.02 μg. Although avoiding the rim region of the glass wafers, we found moderate inhomogeneities of several chalcophile/siderophile elements and gross inhomogeneities of Ni, Se, Pd and Pt at small test portion masses. The extent of inhomogeneity was included in the determination of uncertainties. While the new reference values agree with the NIST certified values with the one exception of Mn in SRM 610, they typically differ by as much as 10% from the Pearce et al. (1997) values in current use. In a few cases (P, S, Cl, Ta, Re) the discrepancies are even higher.



Nous presentons des nouvelles valeurs de reference pour les verres NIST SRM 610–617 en suivant les recommandations de l’ISO et le protocole de l’IAG. Les incertitudes au niveau de confiance de 95% ont ete determinees a des fins d’analyse totale et de micro-analyse. Contrairement aux procedures de compilation precedentes, cette approche fournit des donnees qui tiennent compte des exigences actuelles dans la qualite des donnees. De nouvelles donnees analytiques et le jeu de donnees presque complet de la base de donnees GeoReM ont ete utilises pour cette etude. La qualite des donnees a ete verifiee par l’application de la fonction de Horwitz et par un examen minutieux des procedures analytiques. Nous avons determine quantitativement les possibles inhomogeneites d’element en utilisant des prises d’essai de masses differentes correspondant a 1, 0.1 et 0.02 μg. Bien que nous ayons evite les zones de bordure des disques de verre, nous avons trouve des inhomogeneites moderees pour plusieurs elements chalcophiles/siderophiles et des inhomogeneites flagrantes de Ni, Se, Pd et Pt pour les prises d’essai de petites masses. La mesure d’inhomogeneite a ete incluse dans la determination des incertitudes. Alors que les nouvelles valeurs de reference sont en accord avec les valeurs NIST certifiees a la seule exception du Mn dans SRM 610, elles sont generalement differentes, avec des ecarts de pres de 10%, des valeurs de Pearce et al. (1997) qui sont d’un usage courant. Dans quelques cas (P, S, Cl, Ta, Re), les ecarts sont encore plus eleves.

Determination of Reference Values for NIST SRM 610–617 Glasses Following ISO Guidelines

Osmium isotopic compositions of mantle xenoliths: A global perspective

THE elevated abundances of highly siderophile elements in the Earth's mantle, relative to what would be predicted from metal–silicate equilibrium, have often been cited as evidence for the accretion to the Earth of a 'late veneer' of chondritic material following core formation1. As rhenium and its decay-product osmium are both highly siderophile, the evolution of the Re–Os isotope system in a terrestrial reservoir provides a robust, time-averaged constraint on the siderophile abundances of the reservoir; thus, the broadly chondritic evolution of Os isotopes in the oceanic upper mantle provides strong support for the late accretion model2,3. But the Re–Os composition of the late veneer is still poorly defined, because the mantle has differentiated into 187Os-enriched and -depleted reservoirs4–7. Here we report a value for the Os isotopic composition of the modern 'primitive upper mantle' (PUM), a hypothetical undifferentiated upper-mantle reservoir. From suites of variably melt-depleted mantle xenoliths from three continents, we derive a minimum 187Os/188Os ratio for PUM of 0.1290 ± 0.0009, by using a correlation between 187Os/188Os and geochemical indices of 'fertility' to extrapolate to the Os isotope ratio of undepleted mantle. Comparing this value to the 187Os/188Os ratios measured in different classes of chrondritic meteorite, we infer that the late veneer had siderophile element abundances similar to those of enstatite or ordinary chondrites (187Os/188Os = 0.1286 ± 0.0010), rather than carbonaceous chondrites (0.1258 ± 0.0005).

The osmium isotopic composition of the Earth's primitive upper mantle

Evidence for a gradual rise of oxygen between 2.6 and 2.5 Ga from Mo isotopes and Re-PGE signatures in shales

Reference materials for geochemical PGE analysis: new analytical data for Ru, Rh, Pd, Os, Ir, Pt and Re by isotope dilution ICP-MS in 11 geological reference materials

A simple and highly selective analytical procedure is presented here for the concentration determination of Ru, Rh, Pd, Re, Os, Ir and Pt via isotope dilution, which is suitable for the investigation of geological and environmental materials. Sample preparation consists of a sample digestion step in a high pressure asher (HPA-S) with concentrated HNO3 and HCl and drying down of the sample solution after the Os concentration was determined via sparging OsO4 into an ICP-MS. After drying and redissolution of the remaining solution the other PGEs are separated on-line from their matrix in a simple cation-exchange column that is coupled to a quadrupole ICP-MS. Through this technique it is possible to monitor in every sample the isotopes of the analytes as well as of those elements that cause isobaric interferences or that potentially cause interferences through molecular species. Concentrations of the two or more isotopic elements can be calculated through isotope ratios, whereas Rh is calculated via the peak area. Data for ultramafic reference materials UB-N and GP13 with concentrations lower than 8 ng g−1 show excellent reproducibilities (n
= 9) for Re, Pd and Pt (2.5–3.9% RSD) and Pt, Ru, Rh, Os and Ir (4.5–7% RSD). It can be demonstrated that a large portion of the higher standard deviations is caused by sample heterogeneity. Road dust (BCR-723) was included to demonstrate the strength of this procedure for the determination of environmental samples. Reproducibilities (n
= 5) for Re, Pt and Os were between 1.2 and 2.3% RSD, 5.2% RSD for Pd and 11% RSD for Rh. Data for Ru and Ir are presented for the first time.

A simple procedure for the determination of platinum group elements and rhenium (Ru, Rh, Pd, Re, Os, Ir and Pt) using ID-ICP-MS with an inexpensive on-line matrix separation in geological and environmental materials

Thomas Meisel

Papers

Osmium isotopic compositions of mantle xenoliths: A global perspective

The osmium isotopic composition of the Earth's primitive upper mantle

Evidence for a gradual rise of oxygen between 2.6 and 2.5 Ga from Mo isotopes and Re-PGE signatures in shales

Reference materials for geochemical PGE analysis: new analytical data for Ru, Rh, Pd, Os, Ir, Pt and Re by isotope dilution ICP-MS in 11 geological reference materials

A simple procedure for the determination of platinum group elements and rhenium (Ru, Rh, Pd, Re, Os, Ir and Pt) using ID-ICP-MS with an inexpensive on-line matrix separation in geological and environmental materials