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Ponding, draining and tilting of the Cerberus Plains; a cryolacustrine origin for the sinuous ridge and channel networks in Rahway Vallis, Mars
•Rahway Vallis is a ∼500km long, branching channel network with a distributed source.•Terrace-like forms bounding Rahway’s basin could be since-tilted, high-stand deposits.•Branching sinuous ridges (SRs) beside the Rahway channels are esker-like in form/size.•No other evidence for glacial SR origin...
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| Published in: | Icarus (New York, N.Y. 1962) N.Y. 1962), 2015-06, Vol.253, p.256-270 |
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| Main Authors: | , , , |
| Format: | Article |
| Language: | English |
| Subjects: | |
| Citations: | Items that this one cites Items that cite this one |
| Online Access: | Get full text |
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| Summary: | •Rahway Vallis is a ∼500km long, branching channel network with a distributed source.•Terrace-like forms bounding Rahway’s basin could be since-tilted, high-stand deposits.•Branching sinuous ridges (SRs) beside the Rahway channels are esker-like in form/size.•No other evidence for glacial SR origin found within the Rahway basin or its margins.•Interpretation: a rapidly filled and drained lake, probably deeply frozen in places.
Rahway Vallis sits within a shallow basin (the “Rahway basin”) in the Cerberus Plains of Mars containing a branching network of channels converging on the basin floor. Using topographic cross-profiles of the channels we have found that they are set within broader, subtly-expressed, valleys. These valleys are shallow (around 15m vertically compared to several kilometres in the horizontal) and have convex to rectilinear slope profiles that are consistent in form across the whole Rahway basin. Both channels and valleys descend and deepen consistently from west to east. The channels typically widen down-slope and increase in width at confluences. The morphology and topology of this channel system are consistent with formation by contributory fluid flow, generated from many distributed sources. The transition between the older heavily cratered terrain and the floor of the Rahway basin is bounded by near-horizontal continuous topographic terraces. Plotting the elevation of the terraces shows that they conform to a plane with a height difference of around 100m east to west for the 300km width of the Rahway basin. We calculate that the volume of material needed to fill the topography up to the level of the plane best fit by the terraces is ∼1500km3. Bordering the channels are sinuous ridges, typically several kilometreslong, 20m across, with heights on the order of 10m. They sometimes form branching networks leading into the channels, but also occur individually and parallel to the channels. The multiple tilted terraces, the channel/valley network with many fluvial-like characteristics, and the distributed source regions, suggest that the landforms within the Rahway basin are unlikely to have formed through purely volcanic processes. Rather, the channels within the Rahway basin are consistent with a genesis requiring the flow of liquid water, and the sinuous ridges with melting of a static ice body that occupied the basin. We suggest a hypothesis of rapid basin filling by fluvial flooding, followed by lake drainage. Drainage could have occur |
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| ISSN: | 0019-1035 1090-2643 |
| DOI: | 10.1016/j.icarus.2015.03.005 |