Methane Clathrates in the Solar System

• Published in: Astrobiology
• Main Authors: Mousis, O., Chassefière, Eric, Holm, N.G., Bouquet, Alexis, Waite, J.H., Geppert, W. D., Picaud, S., Aikawa, Yuri, Ali Dib, Mohamad, Charlou, Jean Luc, Rousselot, Philippe
• Other Authors: Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté COMUE (UBFC)-Université Bourgogne Franche-Comté COMUE (UBFC), Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Department of Geological Sciences Stockholm, Stockholm University, The University of Texas at San Antonio (UTSA), Space Science and Engineering Division San Antonio, Southwest Research Institute San Antonio (SwRI), Department of Physics Stockholm, Stockholm University Astrobiology Centre, Department of Earth and Planetary Sciences Kobe, Kobe University, Unité Géosciences Marines (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), ANR-11-IDEX-0001,Amidex,INITIATIVE D'EXCELLENCE AIX MARSEILLE UNIVERSITE(2011)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: Methane clathrate; Protosolar nebula; Terrestrial planets; Outer Solar System; [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]; Ice; permafrost
• Online Access: https://hal.science/hal-01153201; https://hal.science/hal-01153201/document; https://hal.science/hal-01153201/file/1510.07693.pdf; https://doi.org/10.1089/ast.2014.1189

International audience We review the reservoirs of methane clathrates that may exist in the different bodies of the Solar System. Methane was formed in the interstellar medium prior to having been embedded in the protosolar nebula gas phase. This molecule was subsequently trapped in clathrates that formed from crystalline water ice during the cooling of the disk and incorporated in this form into the building blocks of comets, icy bodies, and giant planets. Methane clathrates may play an important role in the evolution of planetary atmospheres. On Earth, the production of methane in clathrates is essentially biological, and these compounds are mostly found in permafrost regions or in the sediments of continental shelves. On Mars, methane would more likely derive from hydrothermal reactions with olivine-rich material. If they do exist, martian methane clathrates would be stable only at depth in the cryosphere and sporadically release some methane into the atmosphere via mechanisms that remain to be determined. In the case of Titan, most of its methane probably originates from the protosolar nebula, where it would have been trapped in the clathrates agglomerated by the satellite's building blocks. Methane clathrates are still believed to play an important role in the present state of Titan. Their presence is invoked in the satellite's subsurface as a means of replenishing its atmosphere with methane via outgassing episodes. The internal oceans of Enceladus and Europa also provide appropriate thermodynamic conditions that allow formation of methane clathrates. In turn, these clathrates might influence the composition of these liquid reservoirs. Finally, comets and Kuiper Belt Objects might have formed from the agglomeration of clathrates and pure ices in the nebula. The methane observed in comets would then result from the destabilization of clathrate layers in the nuclei concurrent with their approach to perihelion. Thermodynamic equilibrium calculations show that methane-rich clathrate layers may exist on Pluto ...