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The GEOROC database includes helpful compilations of mineral compositions aggregated from measurements reported in decades worth of publications, but it can be challenging to consistently filter mislabeled, inaccurate, or incomplete mineral compositions. MIST (Mineral Identification by Stoichiometry) is a stoichiometry-based computational algorithm that identifies geochemical observations with normalized elemental ratios matching natural minerals. The stoichiometric filters that were manually coded in MIST for over 240 mineral species are based on reported mineral formulas and well-documented examples of mineral chemistry reported in RRUFF and associated databases, typically including a ~5-10% tolerance in stoichiometric ratios based on measurement errors, vacancies, and substitutions. The MIST model can therefore efficiently filter the GEOROC mineral compilation files to recognize compositions whose normalized oxides match the labeled mineral stoichiometry. Furthermore, the MIST output includes results of intermediate data manipulation steps, a detailed stoichiometric formula for each input composition, and consistently calculated mineral endmembers such as Fo, En, Ws, and Fs. MIST is agnostic to the instrument used to collect oxide data. Because MIST uses normalized oxides, it cannot distinguish between some mineral species, where applicable, they are reported as a group (e.g., gypsum/bassanite/anhydrite). MIST can only recognize minerals encoded in the algorithm, so other real but less common minerals will not be recognized. The full list of minerals MIST can recognize, along with more details of the algorithm and results pages, are published in Siebach et al. (https://doi.org/10.1016/j.cageo.2025.106021). This dataset includes fifteen of the Compiled Mineral files published by GEOROC in 12-2024 including the MIST results (whether or not a species was confirmed by MIST). Prior to running the data through MIST, all files were filtered to only include mineral compositions that included major oxides (e.g., silicate mineral compositions where SiO2 > 0 wt%). Furthermore, all variations of reported Fe were collapsed into a single column representing FeOT. Metadata is preserved from the original compiled GEOROC files, so users may add additional filters as appropriate for different purposes. Results have not been filtered for reported sum of total oxides, but doing so can help identify particular mineral species (e.g., separate gypsum from bassanite). An additional file preserves the full reference information for each mineral compilation. We suggest using the compositions that MIST identifies as stoichiometrically consistent with a mineral species as a standardized filter on the GEOROC datasets prior to utilizing the data in machine learning models or similar applications. These may also be helpful any time a user would like standardized formulas or mineral endmember information for these mineral compilations.
The data were generated in two labotories of the Dalhousie University in Halifax during a series of experiments to determine the solubility of chromite in komatiite mixed with different crustal contaminants. The experiments were designed to determine the solubility of the mineral chromite in silicate melt, with the dominant variable being the silica and iron content of the melt. After equilibrating chromite with melt at 1192-1430 degrees Celcius, samples were quenched and the composition of the chromite, quenched melt (now glass), and olivine run-products were measured for major and minor elements by electron microprobe, and the chromium concentration in the glass was measured by laser ablation ICP-MS. Analytical procedures are included in the associated data description file. The data are provided in a series of Excel worksheets containing five data tables. Table 1 is a summary of the composition of the starting materials used in experiments. Table 2 is a summary of the conditions of temperature, oxygen fugacity, experiment duration and initial sample composition. Table 3 is a summary of the major and minor element composition of the glass measured by electron microprobe and laser ablation ICP-MS. Tables 4 and 5 are summaries of the major and minor element composition of the olivine and chromite, respectively, measured by electron microprobe.
Carbonate minerals of the dolomite-ankerite and magnesite-siderite series are often found in sedimentary basins associated with economically viable ore deposits and as alteration product of Ca-Mg-Fe-silicates in igneous and metamorphic rocks. Analysis of oxygen and carbon isotopes in such carbonates gives important information, among others, on their evolution and spatial distribution during sediment burial and diagenesis, crystallization temperature during sedimentation, diagenesis and hydrothermal alteration, fluid and carbon sources, mechanisms of CO2 sequestration (e.g., (Śliwiński et al., 2016, 2018 and references therein). Because of their common chemical zoning at the microscale, in-situ techniques such as Secondary Ion Mass Spectrometry (SIMS) are fundamental to unravel intragrain and intergrain isotopic heterogeneities at scales < 50 µm. Due to instrumental artifacts, SIMS analyses need to be calibrated with matrix-matched reference materials to be accurate. This dataset describes a newly compiled set of Ca-Mg-Fe carbonates that were characterized for their mineralogical (XRD), major and minor element chemical composition (EPMA), oxygen and carbon isotopic composition by acid digestion gas-source isotope ratio mass spectrometry (GS-IRMS), and oxygen and carbon isotopic homogeneity at the microscale (SIMS). Three dolomites and one ankerite with Fe# (molar Fe/(Fe+Mg)) ranging from 0.0004 to 0.3429, one magnesite (Fe# = 0.0099) and one siderite (Fe# = 0.6152) are now available for the global SIMS community.
The island of Holsnøy is located in southwestern Norway. It is composed of metastable granulite facies lower crust that was subducted at 430 Ma when fluid infiltrated the region and reacted with large portions of the area to form eclogite facies shear zones. The eclogite facies assemblages contain garnet with granulite facies cores and eclogite facies fractures and rims. This dataset contains quantitative electron microprobe transects from garnets from four different eclogite facies samples. They are divided into two groups: rim profiles that run from the garnet rims toward the cores, and fracture profiles that run perpendicular to eclogite facies fractures. Some profiles have 5–10 µm spacing and were collected at 15 kV accelerating voltage whereas others have 1 µm spacing and were collected at 10 kV which reduced analytical convolution and facilitated higher spatial resolution of the profiles.
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.
This data publication contains mineralogical, geochemical and magnetic susceptibility data of an 87.2 m deep profile of hydrothermally altered plutonic rock in a semi-arid region of the Chilean Coastal Cordillera (Santa Gracia). The profile was recovered during a drilling campaign (March and April 2019) as part of the German Science Foundation (DFG) priority research program SPP-1803 “EarthShape: Earth Surface Shaping by Biota” which aims at understanding weathering of plutonic rock in dependency on different climatic conditions. The goal of the drilling campaign was to recover the entire weathering profile spanning from the surface to the weathering front and to investigate the weathering processes at depth. To this end, we used rock samples obtained by drilling and soil/saprolite samples from a manually dug 2 m deep soil pit next to the borehole. To elucidate the role of iron-bearing minerals for the weathering, we measured the magnetic susceptibility, determined the mineral content and analysed the geochemistry as well as the composition of Fe-bearing minerals (Mössbauer spectroscopy) in selected samples.
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.
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