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Laser ablation inductively coupled mass spectrometry trace elements analyses of Li-rich micas of Pan-African pegmatites in Mozambique

This data report presents the in-situ LA-ICP-MS trace element geochemistry of the micas of the Pan-African rare-element pegmatites of the Alto Ligonha Pegmatite District in northern Mozambique. The pegmatites contain Li-rich micas and primary Li aluminosilicates, such as spodumene. Five Alto Ligonha pegmatites, Naípa, Muiâne, Napepesso West, Nanro, and Natxepo, were investigated to better understand the fractionation of pegmatite melts leading to Li enrichment, utilizing e.g. the trace element chemistry of mica from different parts of these pegmatites. Micas collected from the wall zone, intermediate zone and core zone of the studied pegmatites show high but also highly variable concentrations of the incompatible elements like Li, Rb, Cs, Be, and Ta. Very strong pegmatite-internal fractionation is recorded by the mica chemistry of the Naípa, Muiâne and Nanro pegmatites. In these pegmatites, Li2O in white micas measured with LA-ICP-MS increases from 0.1-1.4 wt.% in the wall zone, to 0.3-1.7 wt.% in the intermediate zone, 1.5-3.8 wt.% in the core zone and up to 5.4 wt.% in the pockets. The data record extreme Li enrichment during the final crystallization stage.

Laser ablation inductively coupled mass spectrometry trace element chemistry of sulfides from the Aouli Ag-Pb-Zn-(Cu) vein system (Upper Moulouya district, Morocco)

This data report presents the in-situ LA-ICP-MS trace element composition of sphalerite, pyrite, and chalcopyrite from the Aouli Ag-Pb-Zn-(Cu) vein system in the Upper Moulouya district, Morocco. The dataset contributes to a study focused on characterizing the element concentrations in sulfides and elucidating the ore-forming processes at the Aouli deposit. Located within the Hercynian inlier of the Upper Moulouya, this deposit hosts one of Morocco’s largest argentiferous Pb-Zn ± F ± Ba vein-type deposits. The mineralization occurs within polyphase hydrothermal veins, oriented NE-SW to E-W and WNW-ESE. These veins occur as lodes, ore shoots, or discontinuous vein infill, with their emplacement largely controlled by structural intersections. The deposit hosts a complex mineralogical assemblage, including Ni-Co-Fe arsenides and sulfarsenides, Pb-Zn-Cu sulfides, and Ag-Sb-As sulfosalts occurring in the same vein structures, which are described for the first time. Consequently, the characterization of pyrite, chalcopyrite, and particularly sphalerite will help constrain the ore-forming process and determine the physicochemical conditions (T–fS2) of the mineralizing fluids.

Major Element and Trace Element Compositions of Tephra Layers Found in European Varved Lake Records

This database contains major and trace element compositions of European tephra and metadata for the datasets and lakes they were found in. It was created by collecting data from scientific literature to support the synchronisation of annually-resolved lake sediment records during the Last Glacial Interglacial Transition (25 ka BP to 8 ka BP). 49 individual tephra layers across 19 varved lake records have been included, with Lago di Grande Monticchio being the largest contributor of geochemical data with 28 layers. The Vedde Ash and Laacher See tephra are the most common layers, being found in 6 different varved records, and highlight the potential of refining the absolute age estimates for these tephra layers using varve chronologies and for synchronising regional paleoclimate archives. This project is the first stage in a 5-years plan funded by the Past Global Changes (PAGES) Data Stewardship Scholarship to incorporate a global dataset of tephra geochemical data in varved sediment records. Further stages of this project will focus on different regions and timescales.

Global cratonic lamproite-orangeite and related potassic rock compositions

Global geochemistry database for cratonic / anorogenic lamproites and related potassic rocks (compiled and screened from GEOROC in April 2020). Related key publication: Ngwenya, Ntando S.; Tappe, Sebastian (2021): Diamondiferous lamproites of the Luangwa Rift in central Africa and links to remobilized cratonic lithosphere. Chemical Geology. https://doi.org/10.1016/j.chemgeo.2020.120019

Copper isotope fractionation during prehistoric smelting of copper sulfides: experimental and analytical data

The project from which the data derived aimed to establish the first systematic study of Cu isotope fractionation during the prehistoric smelting and refining process. For this reason, an experimental approach was used to smelt sulfide copper ore according to reconstructed prehistoric smelting models. The ore was collected by E. Hanning as part of her PhD thesis work from a Bronze Age mining site, the Mitterberg region, Austria (Hanning and Pils 2011) and was made available for the experiments.All starting materials for the experiments such as the natural ore, roasted ore, construction clay, flux, dung (used for the roasting), wood and charcoal (fuel) were natural materials. All firing conditions including the amount of fuel or charging material and the temperatures in the furnaces were recorded, and the experimental procedures were documented in the very detail. In total, 30 experiments were carried out in 4 experimental series. The smelting products, both intermediate products and final products were sampled during or after the respective experiment. Slag, matte and copper metal were the major smelting products. All other materials used in and produced by the experiments were sampled, too. Materials used and produced in the two most promising experimental series with regard to potential Cu isotope fractionation were analyzed. Based on the analytical results, the potential of Cu isotopes as a tool in archaeometallurgical research was systematically evaluated and consequences for the copper isotope application as a provenance tool in archaeometry were identified.The data include the documentation of the experiments, laboratory procedures and analytical methods. An experimental outline was previously published in Rose et al. (2019). Analytical methods applied were ICP-MS (elemental analysis, 80 samples), MC-ICP-MS (copper isotopes, 98 samples), and XRD (phase analysis, 25 samples). The experiments were carried out at the Römisch-Germanisches Zentralmuseum, Labor für Experimentelle Archäologie, Mayen, Germany. Laboratories used for the analytical part of the project were the research laboratories at the Deutsches Bergbau-Museum Bochum and FIERCE (Frankfurt Isotope and Element Research Center), Goethe-University Frankfurt, both Germany. Data were processed and plots created with R (R Core Team 2019) in RStudio®. Data are provided as data tables or text files, the R scripts used to create the time-temperature plots of the smelting experiments are also included.The full description of the data and methods is provided in the data description file.

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