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This content will become publicly available on January 1, 2026

Title: Molecular H2 in silicate melts
A series of hydrothermal diamond anvil cell experiments was conducted to constrain the equilibrium distribution of molecular H2 between H2O-saturated sodium aluminosilicate melts and H2O at elevated temperatures (600 – 800 °C) and pressures (317 – 1265 MPa). The distribution of H2 between the silicate liquid and the aqueous fluid was achieved through real-time monitoring of the H-H stretching vibration under in situ conditions using Raman vibrational spectroscopy. Results show that the solubility of H2 in silicate melts saturated with H2O decreases as the temperature increases, with control exerted by the mole fraction of H2O in the melt. The dissolution of H2 in the hydrous silicate melts appears to follow Henrian behavior, resembling that of an inert, neutral non-polar species. The implications are extended into developing an understanding of the H partitioning between H2-rich atmospheres blanketing magma oceans in the early history of planetary bodies. For example, transferring H from primordial atmospheric envelopes to the interior of rocky exoplanets may be less efficient than previously believed, which should be considered in models of volatile retention. Experimental data also suggest that minimal amounts of solar nebula H2 are likely to dissolve in the molten surface of primitive objects in the protoplanetary disk (~10-5 to 10-9 mole faction H2 in melt), contradicting the highly reducing conditions observed in chondrule mineral compositions.  more » « less
Award ID(s):
2308386 1761388
PAR ID:
10580249
Author(s) / Creator(s):
Publisher / Repository:
Elsevier and Zenodo (https://doi.org/10.5281/zenodo.11527174)
Date Published:
Journal Name:
Geochimica et Cosmochimica Acta
Volume:
389
Issue:
C
ISSN:
0016-7037
Page Range / eLocation ID:
125 to 135
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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