ALBERT

Description: Water is a key parameter in magma genesis, magma evolution, and resulting eruption styles, because it controls the density, the viscosity, as well as the melting and crystallization behavior of a melt. The parental water content of a magma is usually measured through melt inclusions in minerals such as olivine, a method which may be hampered, however, by the lack of melt inclusions suitable for analysis, or post-entrapment changes in their water content. An alternative way to reconstruct the water content of a magma is to use nominally anhydrous minerals (NAMs), such as pyroxene, which take up low concentrations of hydrogen as a function of the magma's water content. During magma degassing and eruption, however, NAMs may dehydrate. We therefore tested a method to reconstruct the water contents of dehydrated clinopyroxene phenocrysts from the Western Canary islands (n=28) through re-hydration experiments followed by infrared and Mössbauer spectroscopy. Employing currently available crystal/melt partitioning data, the results of the experiments were used to calculate parental water contents of 0.71 ±0.07 to 1.49 ±0.15 wt. % H 2 O for Western Canary magmas during clinopyroxene crystallization at upper mantle conditions. This H 2 O range is in agreement with calculated water contents using plagioclase-liquid-hygrometry, and with previously published data for mafic lavas from the Canary Islands and comparable ocean island systems elsewhere. Utilizing NAMs in combination with hydrogen treatment can therefore serve as a proxy for pre-eruptive H 2 O contents, which we anticipate becoming a useful method applicable to mafic rocks where pyroxene is the main phenocryst phase. This article is protected by copyright. All rights reserved.

Description: Global warming will jeopardize the persistence and genetic diversity of many species. Assisted colonization, or the movement of species beyond their current range boundary, is a conservation strategy proposed for species with limited dispersal abilities or adaptive potential. However, species that rely on photoperiodic and thermal cues for development may experience conflicting signals if transported across latitudes. Relocating multiple, distinct populations may remedy this quandary by expanding genetic variation and promoting evolutionary responses in the receiving habitat - a strategy known as assisted gene flow. In order to better inform these policies, we planted seeds from latitudinally distinct populations of the annual legume, Chamaecrista fasciculata , in a potential future colonization site north of its current range boundary. Plants were exposed to ambient or elevated temperatures via infrared heating. We monitored several life history traits and estimated patterns of natural selection in order to determine the adaptive value of plastic responses. To assess the feasibility of assisted gene flow between phenologically distinct populations, we counted flowers each day and estimated the degree of temporal isolation between populations. Increased temperatures advanced each successive phenological trait more than the last, resulting in a compressed life cycle for all but the southern-most population. Warming altered patterns of selection on flowering onset and vegetative biomass. Population performance was dependent on latitude of origin, with the northern-most population performing best under ambient conditions and the southern-most performing most poorly, even under elevated temperatures. Among-population differences in flowering phenology limited the potential for genetic exchange among the northern and southern-most populations. All plastic responses to warming were neutral or adaptive, however photoperiodic constraints will likely necessitate evolutionary responses for long-term persistence, especially when involving populations from disparate latitudes. With strategic planning, our results suggest that assisted colonization and assisted gene flow may be feasible options for preservation. This article is protected by copyright. All rights reserved.

Description: We present new reference values for nineteen USGS, GSJ, and GIT-IWG rock reference materials that belong to the most accessed samples of the GeoReM database. The determination of the reference values and their uncertainties at the 95% confidence level follows as closely as possible ISO guidelines and the Certification Protocol of the International Association of Geoanalysts. We used analytical data obtained by state-of-the-art techniques published mainly in the last 20 years and available in GeoReM. The data are grouped into four categories of different levels of metrological confidence, starting with isotope dilution mass spectrometry as a primary method. Data quality was checked by careful investigation of analytical procedures and by the application of the Horwitz function. As a result, we assign a new and more reliable set of reference values and respective uncertainties for major, minor and a large group of trace elements of the nineteen investigated rock reference materials. This article is protected by copyright. All rights reserved.

Description: Controlling the accuracy and precision of geochemical analyses requires the use of characterized reference materials with matrices similar to those of the unknown samples being analyzed. We report a comprehensive Pb-Sr-Nd-Hf isotopic and trace element concentration dataset, combined with quantitative phase analysis by XRD Rietveld refinement, for a wide range of mafic to ultramafic rock reference materials analyzed at the Pacific Centre for Isotopic and Geochemical Research, University of British Columbia. The samples include a pyroxenite (NIM-P), five basalts (BHVO-2, BIR-1a, JB-3, BE-N, GSR-3), a diabase (W-2), a dolerite (DNC-1), a norite (NIM-N), and an anorthosite (AN-G); results from a leucogabbro (Stillwater) are also reported. Individual isotopic ratios determined by MC-ICP-MS and TIMS, and multi-element analyses by HR-ICP-MS are reported with 4-12 complete analytical duplicates for each sample. The basaltic reference materials have coherent Sr and Nd isotopic ratios with external precision below 50 ppm (2SD) and below 100 ppm for Hf isotopes (except BIR-1a). For Pb isotopic reproducibility, several of the basalts (JB-3, BHVO-2) require acid leaching prior to dissolution. The plutonic reference materials also have coherent Sr and Nd isotopic ratios (〈50 ppm), however, obtaining good reproducibility for Pb and Hf isotopic ratios is more challenging for NIM-P, NIM-N, and AN-G due to a variety of factors, including post-crystallization Pb mobility and the presence of accessory zircon. Collectively, these results form a comprehensive new database that can be used by the geochemical community for evaluating the radiogenic isotope and trace element compositions of volcanic and plutonic mafic-ultramafic rocks. This article is protected by copyright. All rights reserved.

Description: Abstract For ~82 million years, the Hawaiian‐Emperor chain volcanoes have sampled the Pacific mantle via the Hawaiian mantle plume, providing evidence that its composition varies on a range of temporal and spatial scales. Hawaiian volcanoes from 0 to 2 Ma are divided into southwestern (Loa) and northeastern (Kea) geographic and geochemical trends that are interpreted to reflect the bilateral chemical structure of the underlying plume and its corresponding deep mantle sources. Older Hawaiian volcanoes that formed between 8 and 3 Ma record a geochemical transition between the Kea‐dominated Northwest Hawaiian Ridge (8 to 49 Ma) and the bilateral trends of the younger Hawaiian Islands. High‐precision Pb isotopic analyses conducted on 55 new shield‐stage samples from two of these key volcanoes, Kauaʻi and Waiʻanae, show that Loa‐like Pb isotopic ratios (e.g., elevated 208Pb*/206Pb*) gradually increase with decreasing age among the northern Hawaiian volcanoes and dominate for over two million years prior to the onset of the bilateral Loa and Kea geochemical trends. Distinct isotopic groups are observed across Kauaʻi and the distribution of Loa and Kea isotopic compositions is rotated relative to that observed on the younger Hawaiian Islands. Protracted Loa compositions and the atypical Loa‐Kea trend on Kauaʻi are accounted for by: 1) the arrival of a voluminous, Loa mantle heterogeneity possibly associated with anchoring of the Hawaiian plume to the Pacific Large Low Shear Velocity Province, and 2) a different orientation of the Pacific plate relative to the Loa‐Kea compositional boundary prior to 2 Ma.

Description: Key Points Literature review for 2017 of 8700 geoanalytical publications. Geochemical and environmental reference materials. A total of 752 selected articles with summaries of target analytes, and relevant reference materials and producers.

Description: Manganese- and iron-rich materials are of major scientific and economic interest in geosciences. Many of them contain microscopic features that provide valuable information. To obtain accurate results, a homogeneous microanalytical reference material for calibration is needed. Several researchers used the Mn-and Fe-rich RMs, JMn-1, NOD-A-1, NOD-P-1 and FeMn-1, for this purpose; therefore they were tested in this study to determine their suitability for microanalyses. Their homogeneity was investigated by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) with two different types of lasers (nano- and femtosecond), with spot and line scan analyses and with different operating parameters, such as spot size, pulse repetition rate and fluence. Since the established manganese nodule RMs revealed inhomogeneities for pg to μg test portions, we also investigated the new synthetic Fe-and Mn-rich RM, FeMnOx-1. The FeMnOx-1 was found to be homogeneous for large (ø 40 μm: 2% RSD repeatability) and small (ø 8–10 μm: 10% RSD repeatability) spot sizes. This homogeneity is in the range of the homogeneous NIST SRM 610 and GSE-1G reference glasses. Furthermore, FeMnOx-1 revealed a large-scale homogeneity within uncertainties of a few per cent, using test portions in the ng range, when measuring four individual mounts of this material. This article is protected by copyright. All rights reserved.

Description: To provide a better understanding of the recently published pure metalorganic NiI species, [Ni(cod)2][Al(ORF)4] (1, cod = 1,5-cyclooctadiene, RF = C(CF3)3), further characterisations were performed and analysed. Thus, the solvation of 1 in THF was examined via EPR, surprisingly disclosing the initiation to a disproportionation reaction to [NiII(THF)6][Al(ORF)4]2 (3) and Ni0. Further studies concerning the ability of 1 to activate small molecules exhibit the formation of a remarkable [Ni3S2(cod)3]2+ cluster (5) in an oxidation reaction with S8, while EPR measurements of the resulting product in a reaction with oxygen indicate a possible coordination of O2. Single crystal X-ray structures as well as extensive spectroscopic analyses of 3 and 5 are described.

Description: This bibliographic review covers the research contained in twenty-one scientific journals with important contributions to geoanalysis and related scientific fields (Table 1, Figure 1). The relevance of well characterised reference materials (RMs) used as calibration materials or quality control samples for precise and accurate analyses is widely known and has often been described, for example, by Jochum and Enzweiler (2014). This article is protected by copyright. All rights reserved.