/* DATA DESCRIPTION:
Citation:	Hansen, Christian T; Lissenberg, C Johan; Kahl, Wolf-Achim; Bach, Wolfgang (2022): Geochemical data from batch experiments simulating hydrothermal troctolite alteration at 300 and 400°C (40 MPa) [dataset bundled publication]. PANGAEA, https://doi.org/10.1594/PANGAEA.949080
Abstract:	Troctolites represent a close analogue to komatiites, a type of rock assumed to have been common on ancient earth and thus associated water-rock reactions likely have been important in buffering ancient ocean chemistry including the earliest environments linked to the emergence of life. Hydrothermal alteration of olivine-rich troctolite was investigated in two laboratory experiments (300°C and 400°C, 40 MPa, 1800 hrs). Forsteritic olivine (Fo91) and anorthite-rich plagioclase (An95) at a mass ratio of 3.5 were reacted with a sodium-chlorite solution (3.2 wt.-% NaCl) at a water-rock ratio between 3.3 and 2.4. Reaction progress and the nature of the occurring alteration was evaluated based on concomitant fluid samples. Major elemental loads (magnesium, aluminum, silica, calcium, sodium via Inductively Coupled Plasma Optical Emission Spectroscopy) were analyzed alongside pH, salinity and concentrations of dissolved gases hydrogen and methane (gas chromatography). In-situ pH at reaction conditions was reconstructed via EQ3/6 thermodynamic modeling based on fluid chemistry. Following an initial spike, magnesium is increasingly buffered at low levels in both experiments. Calcium experiences an even higher initial spike but is eventually leveling at high levels. Silica is buffered at exceptionally low levels at 300°C but at comparably high level at 400°C. Simultaneously, pH during the reaction is alkaline at 300°C but neutral or slightly acidic at 400°C. Both experiments produce mmol/L concentrations of hydrogen (H2), but considerably more H2 is formed at 300°C. Methane (CH4) formation is very limited but considerably higher at 400°C and at the higher temperature, both, H2 and CH4 levels decrease towards the termination of the experiments.
Keyword(s):	experimental data; fluid-rock interaction; hydrogen; hydrothermal systems; Methane; troctolite alteration
Supplement to:	Hansen, Christian T; Lissenberg, C Johan; Kahl, Wolf-Achim; Bach, Wolfgang (2022): Hydrothermal troctolite alteration at 300 and 400 °C: Insights from flexible Au-reaction cell batch experimental investigations. American Mineralogist, 107(6), 1100-1115, https://doi.org/10.2138/am-2021-7832
Project(s):	Center for Marine Environmental Sciences (MARUM) (URI: https://www.marum.de/en/)
Funding:	German Research Foundation (DFG) (URI: http://www.dfg.de/en/), grant/award no. 222826231: DFG Koselleck project grant BA 1605/10-1 (URI: https://gepris.dfg.de/gepris/projekt/222826231)
	German Research Foundation (DFG) (URI: http://www.dfg.de/en/), grant/award no. 390741603: EXC 2077: The Ocean Floor – Earth's Uncharted Interface (URI: https://gepris.dfg.de/gepris/projekt/390741603)
License:	Creative Commons Attribution 4.0 International (CC-BY-4.0) (URI: https://creativecommons.org/licenses/by/4.0/)
Size:	5 datasets
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/* TABULAR SUMMARY OF DATASETS LISTED IN THIS COLLECTION: */
Filename	Citation of child dataset
Hansen-etal_2022_Table_1.tab	Hansen, Christian T; Lissenberg, C Johan; Kahl, Wolf-Achim; Bach, Wolfgang (2022): Fluid geochemical data from batch experiments simulating hydrothermal troctolite alteration at 300 and 400°C (40 MPa). https://doi.org/10.1594/PANGAEA.949041
Hansen-etal_2022_Table_3.tab	Hansen, Christian T; Lissenberg, C Johan; Kahl, Wolf-Achim; Bach, Wolfgang (2022): Mineral chemistry data from batch experiments simulating hydrothermal troctolite alteration at 400°C (40 MPa). https://doi.org/10.1594/PANGAEA.949054
Hansen-etal_2022_Table_4.tab	Hansen, Christian T; Lissenberg, C Johan; Kahl, Wolf-Achim; Bach, Wolfgang (2022): Mass balance and comparative thermodynamic reaction path data for batch experiments simulating hydrothermal troctolite alteration at 300 and 400°C (40 MPa). https://doi.org/10.1594/PANGAEA.949079
Hansen-etal_2022_Table_S1.tab	Hansen, Christian T; Lissenberg, C Johan; Kahl, Wolf-Achim; Bach, Wolfgang (2022): Detailed mineral proportion reconstruction for batch experiments simulating hydrothermal troctolite alteration at 300 and 400°C (40 MPa). https://doi.org/10.1594/PANGAEA.949074
Hansen-etal_Table_2.tab	Hansen, Christian T; Lissenberg, C Johan; Kahl, Wolf-Achim; Bach, Wolfgang (2022): Mineral chemistry data from batch experiments simulating hydrothermal troctolite alteration at 300°C (40 MPa). https://doi.org/10.1594/PANGAEA.949046
