Evans, A, Thompson, S, Kennedy, H, Butler, B, Day, S and Safi, E (2021) Laboratory exploration of mineral precipitates from Europa’s subsurface ocean. Journal of Applied Crystallography, 54 (5). pp. 1455-1479. ISSN 0021-8898

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The precipitation of hydrated phases from a chondritic-like Na-Mg-Ca-SO4-Cl solution is studied using in situ synchrotron X-ray powder diffraction, under rapid (360
K hour−1, T = 250-80 K, t = 3 hours) and ultra-slow (0.3 K day−1, T= 273-245K, t = 242 days) freezing conditions. The precipitation sequence under slow cooling initially follows the predictions of equilibrium thermodynamics models, however after ∼ 50 days at 245 K, the formation of the highly hydrated sulphate phase Na2Mg(SO4)2·16H2O, a relatively recent discovery in the Na2Mg(SO4)2-H2O system, was observed. Rapid freezing, on the other hand, produced an assemblage of multiple phases which formed within a very short timescale (≤4 minutes, ∆T = 2 K) and, although remaining present throughout, varied in their relative proportions with
decreasing temperature. Mirabilite and meridianiite were the major phases, with pentahydrite, epsomite, hydrohalite, gypsum, bl¨odite, konyaite and loweite also observed. Na2Mg(SO4)2·16H2O was again found to be present and increased in proportion relative to other phases as the temperature decreased. Results are discussed in relation to possible implications for life on Europa and application to other icy ocean worlds.

Item Type: Article
Additional Information: This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
Uncontrolled Keywords: Europa, icy moons, low-temperature mineral precipitation, ocean worlds, long-duration studies
Subjects: Q Science > Q Science (General)
Q Science > QD Chemistry
Q Science > QE Geology
Divisions: Faculty of Natural Sciences > School of Chemical and Physical Sciences
Depositing User: Symplectic
Date Deposited: 10 Sep 2021 14:14
Last Modified: 10 Feb 2022 15:20
URI: https://eprints.keele.ac.uk/id/eprint/9935

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