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To allow the analysis of hydrogen in spinel-structured oxides (hereafter referred to as “spinels”) by secondary ion mass spectrometry, Relative Sensitivity Factors (RSFs), which are typically matrix-dependent, need to be determined. Matrices in natural spinels vary significantly due to the wide range of solid solutions that these nominally anhydrous minerals display. Previous work (Zellmer et al., 2025) has presented RSF values of 16O2H relative to 18O for five natural spinels of variable Al2O3 content. Using the same implanted crystals, we have here expanded this dataset with additional spinels, applying depth profiling under different conditions in a different laboratory. We provide the RSF values of 16O2H relative to 18O, which match the previously available data. We also provide the RSF values of 2H relative to 18O. This in principle allows analysis not only of the OH dimer, but also the H monomer for hydrogen analysis in spinels. However, we note that the significantly higher RSF values for 2H, here between 1.12 x 10^22 and 3.01 x 10^22 atoms per cm3, suggest dimer analysis is preferable because hydrogen monomer count rates will be low. For the RSF of 16O2H relative to 18O, our data confirm an increase with increasing Al2O3 content, here from 2.59 x 10^20 to 2.51 x 10^21 atoms per cm3. When we combine our new data and those of Zellmer et al. (2025), the increase of this RSF with Al2O3 follows a second order polynomial form: RSF = 1.52 x 10^17 Al2O3^2 + 2.12 x 10^19 Al2O3 + 2.76 x 10^20, yielding an r2 value of 0.974, where r is the correlation coefficient. The relative uncertainties in the RSF values based on repeat analyses are circa ±35% (2SE) for 2H relative to 18O and circa ±23% (2SE) for 16O2H relative to 18O, again suggesting that hydrogen analysis should target the OH dimer rather than the H monomer. One ilmenite sample gave RSF values of 3.40 x 10^22 atoms per cm3 (±39.2%, 1RSD) for 2H, and 8.11 x 10^20 atoms per cm3 (±0.5%, 1RSD) for 16O2H. This sample will, however, not be considered further here.
Accurate analyses by Secondary Ion Mass Spectrometry (SIMS) require the use of matrix-matched reference materials due to instrumental mass fractionation. The goal of this data publication is to report a first SIMS homogeneity test of experimentally produced basaltic glasses (Shishkina et al. 2010, Shishkina 2012) to evaluate their potential use as internal reference materials (RMs) for quantification of H2O and CO2 in the GFZ SIMS laboratory. These samples were originally prepared to shed light on magma storage and pre-eruptive conditions as well as degassing paths of natural basaltic systems. The GFZ SIMS laboratory has mm-size chips of 13 samples in total mounted in the centre of an epoxy disc with a diameter of 25.4 mm. All analysed basaltic glasses are relatively homogeneous at the microscale, with relative standard deviations (1RSD) of 1.9 to 15.1% for C/Si, 1.6 to 6.5% for OH/Si and 0.4 to 4.5% for SiH/Si. While the relationship of measured C/Si ratios versus nominal CO2/SiO2 concentrations is described by a linear function, the relationships of OH/Si and SiH/Si ratios versus nominal H2O/SiO2 concentrations are described by quadratic functions. Eight samples (M2, M5, M6, M30, M39, M43, M70 and N72) can be used to quantify CO2 by SIMS in basaltic glasses with concentrations up to 5943 µg/g. Nine samples (M2, M5, M22, M30, M39, M43, M49, M70 and N72) can be used to quantify H2O in basaltic glasses with concentrations up to 8.81 wt.%. We note that H2O quantifications using the measured SiH/Si ratios are less accurate than those using the OH/Si ratios, hence we recommend using the latter. Measured backgrounds in the blank glass N72 were ca. 10 µg/g for CO2 and 0.06 wt.% for H2O. The relative uncertainties on CO2 and H2O calculated values (i.e., SIMS bias) are 12 to 25% (CO2 < 1000 µg/g) and ca. 13% (H2O < 1 wt.%). At higher concentrations (CO2 > 3000 µg/g and H2O > 1 wt.%), uncertainties are lower (2 to 5% for carbon and < 6% for water). In addition to the SIMS data, we provide the synthesis conditions, chemical compositional data, and bulk H2O and CO2 contents of the investigated basaltic glasses.
Spinel-structured oxides (hereafter referred to as ‘spinels’) are a group of nominally anhydrous minerals characterized by a wide range of solid solutions. To allow the analysis of hydrogen in spinels by secondary ion mass spectrometry, Relative Sensitivity Factors (RSFs), which are typically matrix-dependent, need to be determined. Anticipating analysis of the OH- dimer rather than the H+ monomer, we present here RSF values of 16O2H relative to 18O for five natural spinels, including franklinite, Fe-bearing spinel, Mg-chromite, magnetite, and jacobsite. The Al2O3 content in the matrix of these crystals ranged from 0.09 wt% to 67.54 wt%. Our data indicate increasing RSF values with increasing Al2O3 content, from 2.76 x 10^20 to 2.72 x 10^21 atoms per cm3, with an RSD for two repeat analyses of about 4.3%. The increase of RSF with Al2O3 follows a second order polynomial form: RSF = 2.27x10^17 Al2O3^2 + 2.05 x10^19 Al2O3 + 3.02 x10^20. Further analyses at other instruments under different analytical conditions will be required to understand how robust the accuracy of these data can be considered. Expanded analyses of the here presented spinels, including depth-profiling, are reported in Zellmer et al. (2025).
Mantle xenoliths are hosted in lavas localized in the Nemby area (25°24' S, 57°32' W; Asunciòn-Sapucai-Villarrica graben, ASV, central Paraguay: Fig.1), where a small melanephelinitite plug (Cerro Nemby), with elliptical topography (800 x 500 m, about 100 m above the plain), contains very abundant mantle xenoliths (10-15% by volume of the plug) together with crustal xenoliths (Comin-Chiaramonti et al., 2001). According to Le Bas (1987), lavas consist of nephelinite and subordinately of ankaratrite (CIPW Ab < 5 wt% e Ne > 20 wt%). The average size of the mantle xenoliths (10-12 cm, max 45 cm, i.e. the largest observed in ASV) and the compositional range (lherzolite to dunite to pyroxenite) make these xenoliths particularly suitable for a study regarding metasomatic processe(s) affecting the Sub-Continental Lithospheric Mantle of central Paraguay. The dunite results to be the most abundant xenolith type in such lavas. In-situ geochemical characterization was performed on silicates and glasses from very fresh xenoliths, which document a large variety of rock types. Five samples were investigated, namely: i) dunite 3209; ii) spinel harzburgite 3284; iii) spinel lherzolite 3293; iv) olivine websterite 3253 and v) olivine clinopyroxenite 3270. The analyses were directly carried out on thin petrographic sections (30 µm thick) of the selected samples.
The Kupferschiefer districts in Central Europe contain some of the world’s highest-grade sediment-hosted stratiform Cu (SSC) deposits (see Borg et al., 2012). The high-grade sulfide mineralization in the organic matter-rich marine mudstones of the Kupferschiefer (T1), and also in the underlying continental sandstones of the uppermost Rotliegend (S1) and overlying Zechstein Limestone (Ca1), in the Saale subbasin (Eastern Germany) are dominantly formed as a replacement of calcite cement (Mohammedyasin et al., 2023). We provide carbonate major element chemistry, carbon isotope composition of organic matter, and calcite carbon and oxygen isotope microanalysis datasets of drill core samples from the Saale subbasin in Eastern Germany. The samples include the uppermost Rotliegend sandstone (S1), Kupferschiefer (T1) mudstones and lowermost Zechstein Limestone (Ca1), referred as the Kupferschiefer system, from three drill cores (Sangerhausen, Allstedt and Wallendorf). For further details, see Mohammedyasin et al. (Chemical Geology, when available).
Tourmaline-cemented magmatic-hydrothermal breccias are a major host to sulphide mineralization in the supergiant Río Blanco–Los Bronces (RB–LB) porphyry Cu-Mo district in central Chile. We made an extensive study of the chemical and boron isotopic composition of tourmaline from this district to shed light on the composition and origin of mineralizing fluids and to test the utility of tourmaline as an indicator mineral by comparing compositions from mineralized and barren breccias. Río Blanco-Los Bronces is a world-class porphyry-type Cu-Mo district of late Miocene age hosted in a granodioritic batholith and related porphyry intrusions in central Chile (33°9’ S latitude, 70°17’W longitude). The porphyry intrusions and related orebodies are distributed along a structurally-controlled NW-SE zone. Mineralization comprises quartz-sulfide veins, disseminated sulfide miner-alization in altered porphyry host rocks and disseminated sulfides in hydrothermal breccias. See Toro et al. (2012) for an overview of the geology, geochronology and mineralization in the district. Descriptions of the mineralized tourmaline breccias are given by Frikken et al. (2005) and Skewes et al. (2003). The data set provided here comprises in-situ chemical analyses of tourmaline by electron microprobe (EPMA) as well as in-situ boron-isotope analyses of tourmaline in the same samples by SIMS. Tourmaline was analysed in 12 samples including 8 from mineralized breccia bodies (Sur-Sur: 4, La Americana: 4), and 2 samples each from barren breccia and nearby granite-hosted tourmaline nodules in the Diamante area. We also give results of mass balance calculations testing the hypoth-esis of a magmatic-hydrothermal origin of the boron.
The stable isotopic composition of pyrite (δ34Spyrite) and barite (δ34Sbarite, δ18Obarite) in marine sedimentary rocks provides a valuable archive for reconstructing the biogeochemical processes that link the sulfur, carbon, and iron cycles. Highly positive δ34Spyrite values that exceed coeval unmodified seawater sulfate (δ34Spyrite > δ34SSO4(SW)), have been recorded in both modern sediments and ancient sedimentary records and are interpreted to result from various biotic and abiotic processes under a range of environmental conditions. A host of processes, including basin restriction, euxinia, low seawater sulfate, dissimilatory microbial sulfate reduction, sulfide reoxidation, and sulfur disproportionation, have been suggested to account for the formation of highly positive δ34Spyrite values in marine environments. Significantly, determining which of these factors was responsible for the pyrite formation is impeded by a lack of constraints for coeval sulfate, with relatively few examples available where δ34Spyrite and proxies for δ34Ssulfate values (e.g., barite) have been paired at high resolution. In the Selwyn Basin, Canada, the Late Devonian sedimentary system is host to large, mudstone-hosted bedded barite units. These barite units have been interpreted in the past as distal expressions of SEDEX mineralization. However, recent studies on similar settings have highlighted how barite may have formed by diagenetic processes before being subsequently replaced during hydrothermal sulfide mineralization. Coincidentally, highly positive δ34Sbarite values have been recorded in such barite occurring coevally with pyrite in diagenetic redox front, where sulfate reduction is coupled to anaerobic oxidation of methane (SR-AOM) at the sulfate methane transition zone (SMTZ). The mechanisms of sulfur cycling and concurrent processes are, nevertheless, poorly constrained. Grema et al. (2021) integrate high-resolution scanning electron microscopy petrography of barite (+ associated barium phases) and pyrite, together with microscale isotopic microanalyses of δ34Spyrite, δ34Sbarite, and δ18Obarite of selected samples from the Late Devonian Canol Formation of the Selwyn Basin. Samples containing both barite and pyrite were targeted to develop paired isotopic constraints on the evolution of sulfur during diagenesis. We have focused on the precise mechanism by which highly positive δ34Spyrite values developed in the Canol Formation and discuss the implications for interpreting sulfur isotopes in similar settings. This data report comprises microscale secondary ion mass spectrometry (SIMS) analyses of the isotopic compositions of pyrite (δ34Spyrite; n= 200) and barite (δ34Sbarite; n= 485, δ18Obarite; n= 338) in nine stratigraphic sections of the Northwest Territories’ part of the Selwyn Basin. Microdrills of regions of interest (n= 54) were made on polished sections to obtain suitable subsamples, using a 4 mm diameter diamond core drill. Several representative subsamples were cast into 25 mm epoxy pucks, together with reference materials (RMs) of pyrite S0302A (δ34S V-CDT = 0.0 ± 0.2‰ (Liseroudi et al., 2021)) and barite S0327 (δ34SV-CDT = 11.0 ± 0.5 ‰; δ18OV-SMOW = 21.3 ± 0.2 ‰ (Magnall et al., 2016)). Microscale isotopic analyses were carried out using Cameca IMS1280 large-geometry secondary ion mass spectrometer (SIMS) operated in multi-collector mode at the NordSIMS laboratory, Stockholm, Sweden. External analytical reproducibility (1 σ) was typically ± 0.04‰ δ34S for pyrite, ± 0.15‰ δ34S, and ± 0.12‰ δ18O for barite. The sample identification, location, and depth are reported in the data files.
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