Geological analysis of Monad Regio, Triton: Possible evidence of endogenic and exogenic processes

Abstract

The surface morphology of Triton is believed to be predominantly influenced by endogenic processes, such as tectonism, volcanism, diapirism and geyser-like eruptions. To understand how some of these processes have reshaped the surface of the satellite during its evolutionary history, we performed a geological analysis of an extended area located in Monad Regio, where several of these endogenic processes may have taken place. We produced a geomorphological map at 1:1,000,000 scale derived from the joint analysis of the Voyager images, a digital elevation model and a roughness map of the study area. Such approach allowed us to delimit with higher accuracy the geomorphological units already known in literature, as planitiae, cantaloupe and smooth terraced terrains, paterae, knobby, and smooth terraced terrains, but it also enabled us to identify new ones (hummocky terrain, inner planitia, inner patera). We reconstructed the relative ages between such terrains, and we found that after an endogenic phase, an exogenic phase could have followed, during which several geological events reshaped the area. These comprise depositional and erosional processes, including the movement of ice and the subglacial flowing of liquid nitrogen. Such observations imply that Monad Regio could be strongly influenced by exogenic processes, perhaps still active today.