A new dry hypothesis for the formation of martian linear gullies
By S. Diniega, C. Hansen, Jim N. McElwaine, C. Hugenholtz, C. Dundas, A. S. McEwen, M. Bourke. 2013
151 citations recorded by the source corpus.
Long, narrow grooves found on the slopes of martian sand dunes have been cited as evidence of liquid water via the hypothesis that melt-water initiated debris flows eroded channels and deposited lateral levees. However, this theory has several short-comings for explaining the observed morphology and activity of these linear gullies. We present an alternative hypothesis that is consistent with the observed morphology, location, and current activity: that blocks of CO2 ice break from over-steepened cornices as sublimation processes destabilize the surface in the spring, and these blocks move downslope, carving out leveed grooves of relatively uniform width and forming terminal pits. To test this hypothesis, we describe experiments involving water and CO2 blocks on terrestrial dunes and then compare results with the martian features. Furthermore, we present a theoretical model of the initiation of block motion due to sublimation and use this to quantitatively compare the expected behavior of blocks on the Earth and Mars. The model demonstrates that CO2 blocks can be expected to move via our proposed mechanism on the Earth and Mars, and the experiments show that the motion of these blocks will naturally create the main morphological features of linear gullies seen on Mars.
Subfields: Astronomy and Astrophysics, Atmospheric Science, Earth-Surface Processes
View Paper: https://www.semanticscholar.org/paper/795f720eba2abb9ae8675f255b319d18a40aabbf
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Citations in the corpus
- Long-term monitoring of martian gully formation and evolution with MRO/HiRISE (2015, background): “However, the greater intensity of the seasonal cycle at higher obliquity (Haberle et al., 2003) could enhance seasonal frost processes for intervals at times before a few hundred ka. The key point is that current processes can produce fresh-appearing gullies on geologically short timescales. This ra”
- Geologic Constraints on Early Mars Climate (2018, background): “Wordsworth, R.; Forget, F.; Millour, E.; Head, J. W.; Madeleine, J.-B.; Charnay, B., 2013, Global modelling of the early martian climate under a denser CO2 atmosphere: Water cycle and ice evolution, Icarus, 222, 1-19.”