Ammonium Sulfate Volcanism on Titan

Primordial ammonia accreted into Titan is unlikely to remain chemically stable in aqueous solution, most likely reacting with sulfate brines leached out of the core. Pockets of ammonium sulfate brine trapped in a methane- clathrate crust as Titan formed are a likely source for cryomagmas which are apparently erupted to the surface. In rising to the surface, melts will entrain small fragments of country rock (i.e. clathrate xenoliths). These xenoliths will decompose as they undergo decompression, potentially powering explosive eruptions at the surface. We present models suggesting that vent velocities of up to 100 m/s are possible, producing 'lava' fountains several kilometers high. Cryoclastic volcanism is a possible explanation for the smaller crateriform pits observed in SAR data, and also for the global abundance of sand-size grains required to form the observed dune fields. For reasonable effusion rates, we calculate that the dune sediment reservoir could have accumulated in less than a million years.