Methane clathrates in the Solar System

TL;DR

This paper reviews the presence, formation, and potential roles of methane clathrates across various bodies in the Solar System, highlighting their significance in planetary evolution and atmospheric processes.

Contribution

It provides a comprehensive overview of methane clathrates' origins, distribution, and possible impact on planetary atmospheres within the Solar System.

Findings

Methane in the Solar System originated from interstellar medium processes.

Methane clathrates formed from crystalline water ice during disk cooling.

Martian methane may result from hydrothermal reactions and be released sporadically.

Abstract

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 in 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.