These data files represent simulations of hydrated cation vacancies in the mantle mineral forsterite (Mg2SiO4) undertaken using the CASTEP atomic scale simulation code (http://www.castep.org/). Results from these simulations allow the structure relative stability of different defect configurations to be compared. Three types of cation vacancies are considered (M1, M2 and Si) each decorated by hydrogen in order to charge balance the system. For M1 and M2 this results in multiple configurations (with hydrogen bonded to different oxygen atoms around the vacant site). For Si there is only one configuration as all four oxygen atoms are bonded to hydrogen for the charge neutral defect. For each configuration input files detail the initial atomic structure of the defect along with simulation parameters. Output files record the progress of the simulation, the final atomic structure, the energy of this structure, and various predicted properties of the structure. Only ASCII output data is included as binary data created by CASTEP is not intended to be portable, and can easily be recreated using the ASCII files.

Synchrotron X-radiography (images) and diffraction data collected to measure rheology of olivine and ringwoodite structured Co2SiO4.

Data were collected on olivine hosted melt inclusions from four Icelandic eruptions: Stapafell, Haleyjabunga, Berserkjahraun and Heilagsdalsfjall. These data were released as part of the paper "The global melt inclusion C/Ba array: Mantle variability, melting process, or degassing?", published in Geochimica et Cosmochimica Acta, with doi: 10.1016/j.gca.2020.09.030. The data collected to place new constraints on the volatile content of the Icelandic mantle source. The data include measurement of C and H by Secondary Ion Mass Spectrometry, lithophile trace elements (including Ba and Nb) by Secondary Ion Mass Spectrometry, and measurement of major element composition of the melt inclusions and their olivine hosts by Electron Probe Microanalysis. The data were collected in 2017-2018, between Edinburgh (NERC ion probe facility) and Cambridge (EPMA).

Microstructural data for rocks in the Shiant Isles Main Sill, presented as a function of stratigraphic height in the sill. The data were published: Holness et al. (2017) Contributions to Mineralogy and Petrology, 172:7. OI 10.1007/s00410-016-1325-x

The data are nanoindentation, high-angular resolution electron backscatter diffraction (HR-EBSD), and transmission electron microscopy data collected on samples of synthetic forsterite bicrystals at room temperature. The data were collected in two samples, with high- and low- angle grain boundaries (HAGB, 60°, [100]/(011) and SB, 13°, [100]/(016)). The EBSD data are the basis for the HR-EBSD calculation. The HR-EBSD results are presented as Matlab data files. The nanoindentation data are categorised as a function of sample (‘ol13’ – low-angle grain boundary; and ‘ol60’ – high-angle grain boundary), and indenter tip geometry (spherical (with a 10 or 5 micron radius) and pyramidal (Berkovich). The data are presented in .xls files. The TEM data are presented as .tif files. The TEM data were collected in specific indents with various distances from the interfaces. These data have been published in the manuscript: : The Role of Grain Boundaries in Low-Temperature Plasticity of Olivine Revealed by Nanoindentation, with the DOI: 10.1029/2023JB026763

The mechanics of olivine deformation play a key role in long-term planetary processes, including the response of the lithosphere to tectonic loading or the response of the solid Earth to tidal forces, and in short-term processes, such as post-seismic creep within the upper mantle. Previous studies have emphasized the importance of grain-size effects in the deformation of olivine. Most of our understanding of the role of grain boundaries in the deformation of olivine is inferred from comparison of experiments on single crystals to experiments on polycrystalline samples, as there are no direct studies of the mechanical properties of individual grain boundaries in olivine. In this study, we use high-precision mechanical testing of synthetic forsterite bicrystals with well characterized interfaces to directly observe and quantify the mechanical properties of olivine grain boundaries. We conduct in-situ micropillar compression tests at high-temperature (700°C) on bicrystals containing low-angle (4• tilt about [100] on (014)) and high-angle (60• tilt about [100] on (011)) boundaries. During the in-situ tests, we observe differences in deformation style between the pillars containing the grain boundary and the pillars in the crystal interior. In the pillars containing the grain boundary, the interface is oriented at ∼ 45° to the loading direction to promote shear. In-situ observations and analysis of the mechanical data indicate that pillars containing the grain boundary consistently support elastic loading to higher stresses than the pillars without a grain boundary. Moreover, the pillars without the grain boundary sustain larger plastic strain. Post-deformation microstructural characterization confirms that under the conditions of these deformation experiments, sliding did not occur along the grain boundary. These observations support the hypothesis that grain boundaries are stronger relative to the crystal interior at these conditions. This data set is associated with the pre-print manuscript with the DOI: 10.22541/essoar.167979601.17867144/v1

Electron backscatter diffraction was used to quantify grain boundary misorientations in experimental samples doped with deuterium-enriched water. The same samples were subsequently studied with nanoSIMS to look for boundary enrichment of D2O. Grain boundary misorientation data were collected using EBSD to test the possibility of misorientation angle dependence on measured D2O concentrations. No clear misorientation dependence was observed. Folders names include the name of the PDRA who collected the data. Data are images, text files (ctf), and other file formats that can be opened using Oxford Instruments EBSD software. Supporting EDS files are available on request

This is supporting data for the manuscript entitled 'DFENS: Diffusion chronometry using Finite Elements and Nested Sampling' by E. J. F. Mutch, J. Maclennan, O. Shorttle, J. F. Rudge and D. Neave. Preprint here: https://doi.org/10.1002/essoar.10503709.1 Data Set S1. ds01.csv Electron probe microanalysis (EPMA) profile data of olivine crystals used in this study. Standard deviations are averaged values of standard deviations from counting statistics and repeat measurements of secondary standards. Data Set S2. ds02.csv Plagioclase compositional profiles used in this study, including SIMS, EPMA and step scan data. Standard deviations for EPMA analyses are averaged values of standard deviations from counting statistics and repeat measurements of secondary standards. Standard deviations for SIMS and step scan analyses are based on analytical precision of secondary standards. Data Set S3. ds03.csv Angles between the EPMA profile and the main olivine crystallographic axes measured by electron backscatter diffraction (EBSD). 'angle100X' is the angle between the [100] crystallographic axis and the x direction of the EBSD map, 'angle100Y' is the angle between [100] crystallographic axis and the y direction of the EBSD map, and 'angle100Z' is the angle between the [100] crystallographic axis and the z direction in the EBSD map etc. 'angle100P' is the angle between the EPMA profile and the [100] crystallographic axis, 'angle010P' is the angle between the EPMA profile and the [010] crystallographic axis, and 'angle100P' is the angle between the EPMA profile and the [001] crystallographic axis. All angles are in degrees. Data Set S4. ds04.csv Median timescales and 1 sigma errors from the olivine crystals of this study. The +1 sigma (days) is the quantile value calculated at 0.841 (i.e. 0.5 + (0.6826 / 2)). The -1 sigma (days) is therefore the quantile calculated at approximately 0.158 (which is 1 - 0.841). The 2 sigma is basically the same but it is 0.5 + (0.95/2). The value quoted as the +1 sigma (error) is the difference between the upper 1 sigma quantile and the median. Likewise the -1 sigma (error) is the difference between the median and the lower 1 sigma quantile. Data Set S5. ds05.xlsx Median timescales and 1 sigma errors from the plagioclase crystals of this study. Results from each of the parameterisations of the Mg-in-plagioclase diffusion data are included: Faak et al, (2013), Van Orman et al., (2014) and a combined expression. Data Set S6. ds06.xlsx Spreadsheet containing the regression parameters and covariance matrices used in this study and in Mutch et al. (2019). Additional versions of the olivine regressions where the ln fO2 is expressed in Pa have been made for completeness. We recommend using the versions where ln fO2 is expressed in its native form (bars).

The dataset consists of elemental compositions determined for olivine and spinel from 13 ocean islands, including Azores, Balleny, Cook-Austral, Crozet, Cape Verde, Fernando de Noronha, Galapagos, Juan Fernandez, Marquesas, Society, Tristan-Gough, Tahiti, and Trindade). These samples were loaned from Sedgwick Museum, University of Cambridge and National History Museum, London, except the Galapagos samples provided by D. Geist. Elemental compositions determined for three secondary standards (San Carlos olivine, MongOl olivine, and NHNM164905 augite) are also included in the dataset. The data were acquired using a Cameca SX100 electron microscope at the Department of Earth Sciences, University of Cambridge, in June, July, August and November 2021. The elements analysed include Mg, Si, Fe, Al, Ca, P, Cr, Mn, and Ni in olivine, and Mg, Si, Fe, Al, Ca, Cr, Mn, and Ti in spinel. Data acquired from each analysis were saved in four txt files, which are for oxide concentrations, elemental concentrations, standard deviation, and detection limit, respectively. The data for ocean island samples were used to calculate olivine crystallisation temperature and mantle potential temperature based on an aluminium-in-olivine thermometer and modelling of mantle melting. All data collected within the project duration are in this dataset.

Mechanical datasets of a creep rig experiment which quantified grain boundary sliding in an olivine bicrystal sample. A single test was performed for 4 x 104 s at a maximum temperature of 1400 °C. The data from the experiment are presented in a spreadsheet of mechanical data (piston force and linear displacement per time and furnace temperature). A picture of the experimental geometry used and electron backscatter and graphs obtained from the mechanical data are included. The results showed that it is possible to simulate boundary sliding along bicrystal surfaces in a creep rig