Titan : Sedimentology on a World of Hydrocarbons

Lorenz, Ralph¹ (1) Johns Hopkins University Applied Physics Laboratory, Laurel, MD

Saturn's giant moon Titan ranks with Mars as an exciting target for exploration and a place to learn from. Its thick nitrogen/methane atmosphere gives it geological and meteorological processes that yield a diverse and remarkably familiar landscape, albeit one made from exotic materials.

The NASA/ESA Cassini mission is yielding a torrent of remote-sensing data about this bizzare world, following up on the in-situ exploration by the Huygens probe which landed on Titan in early 2005. A picture is emerging of a world where ice boulders are rounded in violent flash-flood streams of liquid methane; where seas of organic-rich sand form giant longitudinal dunes, sculpted by tidally driven winds; and where high latitudes are dotted with lakes of ethane. Our maps of Titan are growing in detail, and are becoming populated with features that are named and understood - the mountains of Xanadu, the sand seas of Belet and Shangri-La.

Titan is literally covered in organics (over 20 different compounds have been identified) - even in the upper atmosphere, 1000km above the surface, benzene and heavier hydrocarbons have been detected. The formation of hydrocarbons and nitriles is driven by photochemical destruction of methane in the atmosphere - the methane in turn may be released via cryo-volcanos from an internal reservoir of methane clathrate.

This talk will summarize the latest findings from Cassini, and our rapidly-evolving understanding of the sedimentological and other processes shaping Titan's surface. Plans for future exploration of Titan, perhaps by balloon, will also be discussed.