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| Titel |
Overland flow erosion inferred from Martian channel network geometry |
| VerfasserIn |
Hansjörg Seybold, James Kirchner |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250127732
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| Publikation (Nr.) |
 EGU/EGU2016-7637.pdf |
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| Zusammenfassung |
| The controversy about the origin of Mars’ channel networks is almost as old as
their discovery 150 years ago. Over the last few decades, new Mars probes have
revealed more detailed structures in Martian The controversy about the origin of Mars’
channel networks is almost as old as their discovery 150 years ago. Over the last few
decades, new Mars probes have revealed more detailed structures in Martian drainage
networks, and new studies suggest that Mars once had large volumes of surface water.
But how this water flowed, and how it could have carved the channels, remains
unclear.
Simple scaling arguments show that networks formed by similar mechanisms
should have similar branching angles on Earth and Mars, suggesting that Earth
analogues can be informative here. A recent analysis of high-resolution data for
the continental United States shows that climate leaves a characteristic imprint in
the branching geometry of stream networks. Networks growing in humid regions
have an average branching angle of α = 2π∕5 = 72∘ [1], which is characteristic of
network growth by groundwater sapping [2]. Networks in arid regions, where overland
flow erosion is more dominant, show much smaller branching angles. Here we
show that the channel networks on Mars have branching angles that resemble those
created by surficial flows on Earth. This result implies that the growth of Martian
channel networks was dominated by near-surface flow, and suggests that deeper
infiltration was inhibited, potentially by permafrost or by impermeable weathered
soils.
[1] Climate’s Watermark in the Geometry of River Networks, Seybold et al.; under
review
[2] Ramification of stream networks, Devauchelle et al.; PNAS (2012) |
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