[Previous] | [Session 46] | [Next]
D.M. Burr (SETI Institute), J.P. Emery (NASA Ames Research Center/SETI Institute), R.D. Lorenz (LPL/University of Arizona), G. Collins (Wheaton College), P.A. Carling (University of Southampton)
Titan is thought to have a hydrocarbon-nitrogen volatile cycle. Volatile cycling on a body with a solid surface entails liquid overland flow. Data from the Cassini-Huygens mission have been interpreted as indicating fluvial channels on Titan. Fluvial channels require both channelized and sheet overland flow, and rely on the resultant sediment transport to form observable features. We present theoretical calculations for sediment transport by liquid overland flow. In this work, methane is taken as the flowing liquid for Titan, and organic material and water ice as the sediment types. For comparison, we complete the same calculations for transport of quartz by water on Earth and basalt by water on Mars. The first calculations describe the conditions for sediment entrainment through calculation of Shields threshold curve for appropriate gravity and liquid and sediment parameters. Settling velocities are then used to describe the type of sediment transport (washload, suspended load, or bedload) that would follow entrainment. These calculations allow derivation of required overland flow depths, flow velocities, and unit discharges for sediment transport over a given slope. Results indicate that material moves more easily on Titan than on Earth or Mars (Burr et al. submitted). Coarse grain transport on Titan may be further enhanced by hyperconcentration of observed organic (fine-grained) sediment (Elachi et al. 2005) during convection-driven rainstorms (Lorenz et al. 2005). Thus, significant sediment transport may occur on Titan during individual overland flow events.
Burr, D.M., J.P. Emery, R.D. Lorenz, G. Collins, P.A. Carling, Sediment transport by liquid overland flow: application to Titan. Icarus, submitted.
Elachi, C. and 34 co-authors 2005. Cassini Radar Views the Surface of Titan. Science, 308, 970-974.
Lorenz, R.D., C. A Griffith, J. I. Lunine, C. P. McKay and N. O. Renno 2005. Convective Plumes and the Scarcity of Clouds on Titan, Geophys. Res. Lett, 32, L01201.
[Previous] | [Session 46] | [Next]
Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.