MODELLING OF VOLCANIC ERUPTIONS ON TITAN

Résumé 0

Observations by the Visual Infrared Spectrometer instrument (VIMS) aboard the Cassini mission haveindicated the possible presence of CO2 ice on the surface on Titan, in areas which exhibit highreflectance in specific spectral windows (McCord et al., 2008). Two of the bright spots of significanceare located within the Xanadu region – Tui Regio (located at 20°S, 130°W) and Hotei Regio (locatedat 26°S, 78°W), and there is a further spot situated in proximity to Omacatl Macula (Hayne et al.,2008). Explosive volcanic eruptions of a cryomagma containing H2O and CO2 are modelled forseveral potential scenarios regarding entrained CO2 clathrates. The model yielded a range of valuescorresponding to the fragmentation pressure in the lava conduit, the velocity of the explodingcryomagma, the height of the associated lava fountain and the potential distance covered by ejecta.The results show that a single vent source does not possess the force required to cover an arearesembling Hotei Regio or Tui Regio. Therefore, we consider alternative origins: the area may havebeen resurfaced by small CO2 grains resulting from multiple explosive eruptions emanating from azone of weakness (Hayne et al., 2008); the characteristics of the area are consequential of an eruptionof cryomagma with CO2 and NH3 components (McCord et al., 2008); or finally, long term seasonalwinds transferred small CO2 grains and distributed them within the limits of Tui Regio area.