Insights From Modelling How Aeolian-Fluvial Interactions Shape the Surface of Titan - SSW

INSIGHTS FROM MODELLING HOW AEOLIAN-FLUVIAL INTERACTIONS SHAPE THE SURFACE OF TITAN - ELENI BOHACEK

Fluvial and aeolian surface processes have been observed on Titan. Methane precipitation feeds fluvial landforms (FLs), 50% of which exhibit rectangular drainage patterns (a much rarer pattern on Earth typically due to conjugate faulting). We developed the Titan Aeolian Fluvial Interactions model to simulate interacting fluvial and aeolian processes on Titan. This landscape evolution model is based on a coupled implementation of the Caesar-Lisflood fluvial model, and Discrete ECogeomorphic AeolianLandscape model (DECAL) dunes model. The Caesar-Lisflood fluvial model routes water over a digital elevation model and calculates erosion and deposition from fluvial and slope processes and changes elevations accordingly. The DECAL model is based on the Werner slab model of dunes, which simulates dune field development through self-organization. We show that although Titan dunes are potentially inactive, they are so much larger relative to rivers that dunes represent major topographic obstacles to rivers. Much like on Earth, we found that the nature of duneriver interactions are dependent on the relative orientations of dune crestlines and the river channel. In some cases, where the river ran semi-parallel to dune crests, the river could be funnelled upslope along interdune corridors, forming rectangular drainage patterns. In other cases when the relative orientations were not parallel, the river would pool and then breach the lower area of a dune crest and flood deeper into the dune field, delivering sediment in the process. These findings help our understanding of FL drainage patterns, distribution, and planforms, and suggest a mechanism for fluvial sediment delivery into dune fields.