Channel morphometry, sediment transport, and implications for tectonic activity and surficial ages of Titan basins

Abstract

Fluvial features on Titan and drainage basins on Earth are remarkably similar despite differences in gravity and surface composition. We determined network bifurcation ( R _b) ratios for five Titan and three terrestrial analog basins. Tectonically-modified Earth basins have R _b values greater than the expected range (3.0-5.0) for dendritic networks; comparisons with R _b values determined for Titan basins, in conjunction with similarities in network patterns, suggest that portions of Titan's north polar region are modified by tectonic forces. Sufficient elevation data existed to calculate bed slope and potential fluvial sediment transport rates in at least one Titan basin, indicating that 75 mm water ice grains (observed at the Huygens landing site) should be readily entrained given sufficient flow depths of liquid hydrocarbons. Volumetric sediment transport estimates suggest that ∼6700-10,000 Titan years (∼2.0-3.0 × 10 ⁵ Earth years) are required to erode this basin to its minimum relief (assuming constant 1 m and 1.5 m flows); these lowering rates increase to ∼27,000-41,000 Titan years (∼8.0-12.0 × 10 ⁵ Earth years) when flows in the north polar region are restricted to summer months.