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| Titel |
Stability of clathrate hydrates in Martian crust |
| VerfasserIn |
Elodie Gloesener, Ozgur Karatekin, Veronique Dehant |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250087020
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| Publikation (Nr.) |
 EGU/EGU2014-985.pdf |
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| Zusammenfassung |
| Clathrate hydrates are crystalline compounds constituted by cages formed by hydrogen-bonded
water molecules inside of which guest gas molecules are trapped. These materials
are typically stable at high pressure and low temperature and are present on Earth
mainly in marine sediments and in permafrost. Moreover, clathrate hydrates are
expected to exist on celestial bodies like the icy moons Titan, Europa or Enceladus.
Current conditions in the Martian crust are favourable to the presence of clathrate
hydrates.
In this study, we focused on the stability of methane and carbon dioxide clathrates in the
Martian crust. We coupled the stability conditions of clathrates with a 1D thermal model in
order to obtain the variations of the clathrate stability zone in the crust of Mars with time and
for different crust compositions. Indeed, the type of soil directly controls the geothermal
conditions and therefore the depth of clathrates formation. Unconsolidated soil acts as a
thermal insulator and prevents the clathrates formation in the crust except on a
small part of a few tens of meters thick. In contrast, sandstone or ice-cemented soil
allows the clathrates formation with a stability zone of several kilometers. This is
explained by the fact that they evacuate heat more efficiently and thus maintain lower
temperatures. We also studied the stability zone of clathrates formed from a mixture of
methane and hydrogen sulphide as well as from a mixture of methane and nitrogen.
Contrary to the addition of N2, the addition of H2S to CH4 clathrates extends the
stability zone and thus brings it closer to the surface. Therefore, mixed clathrates
CH4-H2S will be more easily destabilized by changes in surface temperature than CH4
clathrates. |
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