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| Titel |
Global distribution of fluvial channels on Titan |
| VerfasserIn |
M. Langhans, R. Jaumann  , K. Stephan, R. H. Brown, B. J. Buratti, R. Clark, K. H. Baines, P. D. Nicholson, R. D. Lorenz |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250026655
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| Zusammenfassung |
| The presence of fluvial erosion on Titan’s surface is an obvious analogy to Earth. This study
investigates the global distribution of fluvial valley systems on Titan. Based on
Cassini-RADAR-data we mapped the allocation of channels, their appropriate flow
direction and morphological properties. A great variety of morphological valley
types ranges from dendritic valleys that certainly developed from precipitation
to a more canyon-like valley type whose development is possibly supported by
groundwater release. Another type of fluvial valleys resembles terrestrial wadis
that evolved as a result of precipitation separated by long-term intervals of dry
periods.
Furthermore, based on a global Cassini-VIMS-mosaic the allocation of fluvial channels
was determined with respect to spectral units. Based on the spectral signature in the infrared
methane windows – expressed as VIMS wavelength ratios composed to a color image (RGB)
– three major units can be distinguished: whitish material which is mainly distributed in the
topographically high areas indicating equal reflectivity in all atmospheric windows; bluish
material that exhibits a higher reflectivity at shorter atmospheric wavelength windows
implying a clear spectral separation from the whitish material, and brownish material
characterized by a higher reflectivity in the longer wavelength atmospheric windows that
correlates with dunes. The majority of channels are exposed on the bright surface unit
while just a few percent of channels are located on the blue and brown surface unit,
respectively.
Fluvial incision has shaped Titan’s surface globally. Nevertheless, from a morphological
point of view as well as concerning the associated VIMS-unit fluvial shaping is not uniform.
The global distribution of channels provides unique information about environmental
conditions and processes forming Titan’s surface. However, to date just 20% of Titans surface
are covered with high resolution data, thus, the current results can only give a first impression
of Titan’s surface erosion. |
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