Evaluation of the possible presence of clathrate hydrates in Europa's icy shell or seafloor

Prieto-Ballesteros, O.; Kargel, Jeffrey S.; Fernández-Sampedro, M.; Selsis, F.; Martínez, Eduardo Sebastián; Hogenboom, D. L.

doi:10.1016/j.icarus.2005.02.021

Cited by 68 publications

(62 citation statements)

References 97 publications

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“…Hersant et al 2008;Prieto-Ballesteros et al 2005;Kargel & Lunine 1998), sometimes extrapolated at low temperatures. In these astrophysical environnements where clathrate hydrates are possibly stable against dissociation, questioning their formation and associated kinetics should readily supersede stability curves determinations.…”

Section: Discussionmentioning

confidence: 99%

Methane clathrate hydrate FTIR spectrum

Dartois¹,

Deboffle²

2008

A&A

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Context. The physical behaviour of methane clathrate hydrate, a crystallographic ice crystal is of major importance for both the earth and the stability of gases in many astrophysical bodies (planets, comets, etc.). Aims. We provide an infrared spectroscopic identification for astrophysical methane clathrate hydrates and investigate the crystal field experienced by the trapped molecule. Methods. A methane clathrate crystal was produced in a moderate-pressure optical cell. Using FTIR spectroscopy, the ν 3 asymmetric CH-stretching mode of the entrapped methane molecule is recorded from 7 K to 80 K, then back to 7 K. Results. It is shown that the trapped methane molecules in the clathrate hydrate is a quasi rotor, displaying gaseous behaviour at low temperatures. A series of ro-vibrational specific lines is observed, shifted in frequency by the water-ice cage interactions with the trapped methane molecules. Because these transitions are unique to methane clathrate hydrate, they represent a crucial identification pattern for astrophysical icy bodies at low temperatures, such as comets and/or interstellar grains.

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Section: Discussionmentioning

confidence: 99%

Methane clathrate hydrate FTIR spectrum

Dartois¹,

Deboffle²

2008

A&A

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“…The density, ρ, of a clathrate depends on the lattice parameter, a, the mass of its water molecules, the mass of the guest molecule and the cage occupancy; it is calculated as follows (Prieto-Ballesteros et al 2005):…”

Section: Densitymentioning

confidence: 99%

“…If this is not the case then the gas concentration would need to be restored by an alternative mechanism, such as hydrothermal activity (Bouquet et al 2015). Prieto-Ballesteros et al (2005) evaluated the stability and calculated the density of several types of clathrates thought to be found in the crust and ocean of Europa using thermal models for the crust. They found SO 2 , CH 4 , H 2 S and CO 2 clathrates should all be stable in most regions of the crust.…”

Section: Introductionmentioning

confidence: 99%

Properties of CO₂clathrate hydrates formed in the presence of MgSO₄solutions with implications for icy moons

Safi

Thompson

Evans

et al. 2017

A&A

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Context. There is evidence to suggest that clathrate hydrates have a significant effect on the surface geology of icy bodies in the Solar System. However the aqueous environments believed to be present on these bodies are likely to be saline rather than pure water. Laboratory work to underpin the properties of clathrate hydrates in such environments is generally lacking. Aims. We aim to fill this gap by carrying out a laboratory investigation of the physical properties of CO 2 clathrate hydrates produced in weak aqueous solutions of MgSO 4 . Methods. We use in situ synchrotron X-ray powder diffraction to investigate clathrate hydrates formed at high CO 2 pressure in ice that has formed from aqueous solutions of MgSO 4 with varying concentrations. We measure the thermal expansion, density and dissociation properties of the clathrates under temperature conditions similar to those on icy Solar System bodies. Results. We find that the sulphate solution inhibits the formation of clathrates by lowering their dissociation temperatures. Hysteresis is found in the thermal expansion coefficients as the clathrates are cooled and heated; we attribute this to the presence of the salt in solution. We find the density derived from X-ray powder diffraction measurements is temperature and pressure dependent. When comparing the density of the CO 2 clathrates to that of the solution in which they were formed, we conclude that they should sink in the oceans in which they form. We also find that the polymorph of ice present at low temperatures is Ih rather than the expected Ic, which we tentatively attribute to the presence of the MgSO 4 . Conclusions. We (1) conclude that the density of the clathrates has implications for their behaviour in satellite oceans as their sinking and floating capabilities are temperature and pressure dependent, (2) conclude that the presence of MgSO 4 inhibits the formation of clathrates and in some cases may even affect their structure and (3) report the dominance of Ih throughout the experimental procedure despite Ic being the stable phase at low temperature.

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“…Pure Ar clathrates may be less dense in the case of partial occupancies, but unless large amounts of Ar are present, these clathrate hydrates should not be stable within icy satellites. If one considers a mixed gas-water system, it appears that clathrate hydrates containing large amounts of methane will tend to be less dense than the liquid layer and thus float beneath the outer ice layer, as may have happened on Titan (Tobie et al 2006;), whereas CH 4 -poor clathrates will tend to sink to the bottom of the liquid layer and thicken the solid layer (Prieto-Ballesteros et al 2005).…”

Section: Density and Segregation Of Materialsmentioning

confidence: 99%

“…Dense hydrated salts and CH 4 -poor clathrate hydrates (see Sect. 3) may form at those conditions and gather as a solid layer at the interface (Kargel et al 2000;Prieto-Ballesteros et al 2005). Such a barrier would have an insulating effect on the silicate portion of the interior, because of the low thermal conductivity of these materials (ranging between 0.5 and 2.5 W m −1 K −1 for clathrates and salt hydrates, respectively).…”

Section: Europa: Sulfates Sulfides and Prolonged Water-rock Interacmentioning

confidence: 99%

Subsurface Water Oceans on Icy Satellites: Chemical Composition and Exchange Processes

et al. 2010

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The state of knowledge about the structure and composition of icy satellite interiors has been significantly extended by combining direct measurements from spacecraft, laboratory experiments, and theoretical modeling. The existence of potentially habitable liquid water reservoirs on icy satellites is dependent on the radiogenic heating of the rock component, additional contributions such as the dissipation of tidal energy, the efficiency of heat transfer to the surface, and the presence of substances that deplete the freezing point of liquid water. This review summarizes the chemical evolution of subsurface liquid water oceans, taking into account a number of chemical processes occuring in aqueous environments and partly related to material exchange with the deep interior. Of interest are processes occuring at the transitions from the liquid water layer to the ice layers above and below, involving the possible formation of clathrate hydrates and high-pressure ices on large icy satellites. In contrast, water-rock exchange is important for the chemical evolution of the liquid water layer if the latter is in contact with ocean floor rock on small satellites. The composition of oceanic floor deposits depends on ambient physical conditions and ocean chemistry, and their evolutions through time. In turn, physical properties of the ocean floor affect the circulation of oceanic water and related thermal effects due to tidally-induced porous flow and aqueous alteration of ocean floor rock.

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Evaluation of the possible presence of clathrate hydrates in Europa's icy shell or seafloor

Cited by 68 publications

References 97 publications

Methane clathrate hydrate FTIR spectrum

Methane clathrate hydrate FTIR spectrum

Properties of CO₂clathrate hydrates formed in the presence of MgSO₄solutions with implications for icy moons

Subsurface Water Oceans on Icy Satellites: Chemical Composition and Exchange Processes

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Evaluation of the possible presence of clathrate hydrates in Europa's icy shell or seafloor

Cited by 68 publications

References 97 publications

Methane clathrate hydrate FTIR spectrum

Methane clathrate hydrate FTIR spectrum

Properties of CO2clathrate hydrates formed in the presence of MgSO4solutions with implications for icy moons

Subsurface Water Oceans on Icy Satellites: Chemical Composition and Exchange Processes

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Properties of CO₂clathrate hydrates formed in the presence of MgSO₄solutions with implications for icy moons