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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.
The datasets include the results of microcosm experiments documenting the generation of hydrogen gas, hydrogen peroxide and dissolved iron from silicate rocks and pyrite at zero deg C after they have been 'flash heated' to different temperatures. The data is in excel format. This data is from an upcoming publication, Flash Heating Boosts the Potential for Mechanochemical Energy Sources for Subglacial Ecosystems' Stone, Jordan., Edgar, John O., Rutherford, Johnny., Gill-Olivas, Beatriz, Tranter, Martyn., Gould, Jamie A., Xavier, Cijo M. & Telling, Jon. Submitted to Frontiers in Geochemistry.
H2 adsorption data on sub-bituminous coal as a function of pressure. Hydrogen flooding of a coal core. Micro CT imaging of the effect on coal swelling after hydrogen injection. Hydrogen is trapped, and no swelling is observed indicating that coal might be a good candidate for the storage of hydrogen.
The data was generated from a range of laboratory experiments where a range of silicate rocks (granite, basalt, peridotite) were crushed in oxygen-free conditions, deoxygenated water added, and the generation of hydrogen gas and hydrogen peroxide followed over a week. Results were compared to rock-free controls. The data was collected to provide insight into the production of oxidants (such as hydrogen peroxide) along tectonically active regions of the subsurface, and how the oxidants might influence subsurface microbiology.
This dataset comprises raw carbon, oxygen and hydrogen stable isotope data on water (precipitation and terrestrial) and plant cellulose from Empodisma-dominated peatlands throughout New Zealand. This data has been published in two open access papers: Amesbury, M. J., Charman, D. J., Newnham, R. M., Loader, N. J., Goodrich, J. P., Royles, J., Campbell, D. I., Roland, T. P. and Gallego-Sala, A. V. 2015. Carbon stable isotopes as a palaeoclimate proxy in vascular plant dominated peatlands. Geochimica et Cosmochimica Acta 164, 161-174. Amesbury, M. J., Charman, D. J., Newnham, R. M., Loader, N. J., Goodrich, J. P., Royles, J., Campbell, D. I., Keller, E. D., Baisden, W. T., Roland, T. P. and Gallego-Sala, A. V. 2015. Can oxygen stable isotopes be used to track precipitation moisture source in vascular plant dominated peatlands? Earth and Planetary Science Letters 430, 149-159.
The dataset gather data from a dual experiment conducted to the study (i) the stress dependence of ultrasonic (elastic) waves and permeability of salt rocks, and (ii) the monitoring of controlled dissolution in an intact halite sample and a cracked (fractured) one. The tests were run in the high-pressure room-temperature (20°C) experimental setup for flow-through tests at the National Oceanography Centre, Southampton (NOCS) (Falcon et al. 2016). The rig consists of a triaxial vessel equipped with (i) ultrasonic sensors that allow measuring P- and S-wave velocities and their attenuation factors using the pulse echo method (McCann and Sothcott, 1992), and (ii) two rigs of electrodes embedded into the rubber sleeve of the pressure vessel for collecting electrical resistivity data that can be used to build up an electrical tomography of the sample (North el al. 2013). The rig has automatic control of both confining and pore pressure (ISCO EX-100D system). For the operating conditions and in homogeneous samples, the bulk electrical resistivity error is <1% for bulk resistivities <100 Ω m, increasing up to 5% with the degree of heterogeneity and above this resistivity value, at frequencies 1–500 Hz (North et al., 2013). Regarding the ultrasonic data, the technique and instrumentation used in this experiment provide velocity precision of ± 0.1% and accuracy of ± 0.3% (95% confidence), and attenuation accuracy of ± 0.1 dB cm-1 within the frequency range 300-1000 kHz (Best, 1992). The dataset presented here show the ultrasonic data at a single frequency of 600 kHz, obtained from Fourier analysis of broadband signals. Permeability to water and to N2 can be both determined with the aid of integrated flowmeters and pore pressure sensors both up- and downstream of the rock sample. The rock samples include: Pre-Cambrian salt (unknown well, Pakistan (source: www.likit.co.uk/)), Cambrian salt (unknown well, Tunguska Basin, Russia), Triassic salt (Arm Hill #1 well, NW Lancashire, UK), and Messinian salt (3A GN3 S02 well, core # 19, near Marianopoli, Sicily). 2.5 cm length, 5 cm diameter core plugs were extracted from precursor rocks, composition estimated by X-ray diffraction analysis, and connected porosity by He-pycnometry. Falcon-Suarez, I., North, L., Amalokwu, K., Best, A., 2016. Integrated geophysical and hydromechanical assessment for CO2 storage: shallow low permeable reservoir sandstones. Geophysical Prospecting 64, 828-847, http://doi.org/10.1111/1365-2478.12396. McCann, C., Sothcott, J., 1992. Laboratory measurements of the seismic properties of sedimentary rocks. Geological Society, London, Special Publications 65, 285-297, https://doi.org/10.1144/gsl.sp.1992.065.01.22. North, L., Best, A.I., Sothcott, J., MacGregor, L., 2013. Laboratory determination of the full electrical resistivity tensor of heterogeneous carbonate rocks at elevated pressures. Geophysical Prospecting 61, 458-470, https://doi.org/10.1111/j.1365-2478.2012.01113.x.