Greater contrast in Martian hydrological history from more accurate estimates of paleodischarge

Correlative width‐discharge relationships from the Missouri River Basin are commonly used to estimate fluvial paleodischarge on Mars. However, hydraulic geometry provides alternative, and causal, width‐discharge relationships derived from broader samples of channels, including those in reduced‐gravi...

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Bibliographic Details
Published in:Geophysical research letters 2016-09, Vol.43 (17), p.8903-8911
Main Authors: Jacobsen, R. E., Burr, D. M.
Format: Article
Language:English
Subjects:
Channels
Correlation
discharge
Estimates
Fluid dynamics
Fluid flow
fluvial
Freshwater
Geometry
geomorphology
Hydraulic geometry
Hydraulics
Hydrology
Mars
Mars (planet)
River basins
terrestrial analog
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Summary:Correlative width‐discharge relationships from the Missouri River Basin are commonly used to estimate fluvial paleodischarge on Mars. However, hydraulic geometry provides alternative, and causal, width‐discharge relationships derived from broader samples of channels, including those in reduced‐gravity (submarine) environments. Comparison of these relationships implies that causal relationships from hydraulic geometry should yield more accurate and more precise discharge estimates. Our remote analysis of a Martian‐terrestrial analog channel, combined with in situ discharge data, substantiates this implication. Applied to Martian features, these results imply that paleodischarges of interior channels of Noachian‐Hesperian (~3.7 Ga) valley networks have been underestimated by a factor of several, whereas paleodischarges for smaller fluvial deposits of the Late Hesperian‐Early Amazonian (~3.0 Ga) have been overestimated. Thus, these new paleodischarges significantly magnify the contrast between early and late Martian hydrologic activity. Width‐discharge relationships from hydraulic geometry represent validated tools for quantifying fluvial input near candidate landing sites of upcoming missions. Key Points Conventional width‐discharge relationship to estimate paleodischarge on Mars is correlative; hydraulic geometry relationships are causal Application to a terrestrial analog river finds width‐discharge relationships from hydraulic geometry to be more accurate and precise New estimates from these width‐discharge relationships increase the contrast in paleodischarge between early and late Mars history
ISSN:0094-8276
1944-8007
DOI:10.1002/2016GL070535