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| Titel |
Geomorphology and surface age of Titan‘s Xanadu Region |
| VerfasserIn |
M. Langhans, J. I. Lunine, G. Mitri |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250067407
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| Zusammenfassung |
| Titan's Xanadu region reveals a multitude of geologic features such as fluvial channels, mountains, and lake-like features; the confluence of all these makes Xanadu special. Nevertheless, the geologic history and interplay of geologic processes remains largely unexplained. Recent studies conclude the region as a whole is ancient (e.g. Wood et al. 2010) based on Xanadu‘s higher crater density with respect to the remaining terrains of Titan. In contrast to that, dense fluvial networks that cover a substantial part of western Xanadu argue for a rather young age of Xanadu. A way to reconcile the two comes from noting that all of Xanadu‘s (seven) craters are located close to the easternmost boundary of the region. While it is reasonable to conclude that eastern Xanadu region is old, it is not justifiable to extend that interpretation to the entire Xanadu region. In fact, Xanadu‘s central and western parts are free of craters based on the radar data. Further, channels of the western Xanadu region have a balanced distribution of azimuths, i.e. the distribution of flow directions of the channel segments in a rose diagram is not uni- or bimodal, as one would expect for a resistant bedrock or a relatively short epoch of fluvial erosion. Thus, although the channels are certainly not filled with liquids today, inferred from their radar-bright tone, Xanadu‘s western regions evidently experienced fluvial incision for a relatively long time. Taken together with the absence of craters, the surface age of the Xanadu‘s western district is in fact quite young. In contrast, Xanadu‘s easternmost parts reveal a substantial number of craters. Some channels which are interspersed in that region show a more directional behavior, with dominant flow directions from east to west and NW to SE, implying a higher degree of tectonic control and thus likely a shorter period of fluvial incision. Xanadu‘s central area is rugged and mountainous, neither exhibiting crater nor features unequivocally identified as fluvial channels. Due to the absence of craters in Xanadu‘s central district and owing to its eroded and degraded appearance (e.g. Radebaugh et al. 2011) it seems reasonable to estimate the relative surface age of this region as relatively young. All in all, the major part of Xanadu appears to be young while a high density of craters argues for an old surface limited to only a small part of Xanadu‘s eastern district. What we interpret as a single geologic province may in fact be a composite of (at least) two separate types of terrains formed at different times, or the evolution of Xanadu has extended over a large part of Titan’s history. |
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