On the Probability of Cryogenic Mud Volcanism on Titan

摘要

Juxtaposing images of the surface of Titan made by the Huygens probe and photos of the mud volcano region on Earth (the Taman peninsula, the Caucasus) reveals similar geomorphologic features. This has led us to suggest the existence of cryogenic mud-volcanic activity on Titan. The role of liquid methane in supporting this process on Titan can be the same as that of gaseous methane on Earth. For Titan, gas hydrates (hydrates of hydrocarbon gases) and water ice are analogs of terrestrial clay breccia. Note that gas hydrates are stable at P-T conditions typical of Titan. Assuming the existence of mud-volcanic activity on Titan allows us to explain: (i) the general view of the landscape near the Huygens probe landing site, (ii) the chains of bright "islets" noticed during the probe descent, which may be a marker of a tectonic fault line, (iii) the conic shape of the hill in the foreground of the image taken from an altitude of 8 km, (iv) the rounded pebble-like shape of the small solid blocks on the surface of Titan, and (v) the presence of long white strips, each of which seems to diverge at one of the ends (such a picture can be produced by methane wind carrying away the ejecta of a gaseous volcano from its crater).