We investigated the scale, slope and curvature properties of gully long profiles on Earth and Mars to ascertain whether gullies on Mars are formed by alluvial and/or debris flow processes. During this investigation we also compared generic slope profiles on Mars to those with gullies

Balme, Matthew

Conway, Susan

Murray, John

Towner, Martin

English

Open Research Online (The Open University)

Open Research OnlineThe Open University’s repository of research publicationsand other research outputsQuantitive analysis of gully long profiles on Earth andMarsConference or Workshop ItemHow to cite:Conway, Susan; Balme, Matthew; Murray, John and Towner, Martin (2010). Quantitive analysis of gully longprofiles on Earth and Mars. In: EGU General Assembly 2010, 2-7 May 2010, Vienna, Austria, p. 9889.For guidance on citations see FAQs.c© 2010 The AuthorsVersion: Version of RecordLink(s) to article on publisher’s website:http://meetingorganizer.copernicus.org/EGU2010/EGU2010-9889.pdfCopyright and Moral Rights for the articles on this site are retained by the individual authors and/or other copyrightowners. For more information on Open Research Online’s data policy on reuse of materials please consult the policiespage.oro.open.ac.ukGeophysical Research AbstractsVol. 12, EGU2010-9889, 2010EGU General Assembly 2010© Author(s) 2010Quantitive analysis of gully long profiles on Earth and MarsSusan Conway (1,2), Matthew Balme (1), John Murray (1), and Martin Towner (3)(1) Department of Earth and Environmental Sciences, Open University, United Kingdom (s.j.conway.00@cantab.net), (2)Laboratoire de Planétologie et Géodynamique de Nantes URM-CNRS 6112, Université de Nantes, Nantes, France, (3)Impacts and Astromaterials Research Centre, Department of Earth Science and Engineering, Imperial College London, UnitedKingdomWe investigated the scale, slope and curvature properties of gully long profiles on Earth and Mars to ascertainwhether gullies on Mars are formed by alluvial and/or debris flow processes. During this investigation we alsocompared generic slope profiles on Mars to those with gullies.To perform these analyses we used digital elevation models (DEMs) for Earth, the majority of which werederived from ∼ 1 m resolution LiDAR data from the UK’s NERC ARSF and the USA’s NSF NCALM. For Marswe used a technique developed by Kreslavsky [1] to extract elevation data from pairs of RDR HiRISE images. Wesuccessfully validated this technique by comparing its results to those from HiRISE DEMs made using automatedstereo photogrammetry techniques [2].We found that gullies produced by debris flow have properties distinct from those formed by alluvial pro-cesses on Earth. In general, debris flow gullies are less concave than alluvial gullies, have a basal concavity andhave higher slopes than alluvial gullies. We then compared our results from Earth to the gully profiles on Mars andfound that properties of gullies on Mars overlap those of both debris flow and alluvial gullies on Earth, however,gullies on Mars are slightly more similar to terrestrial debris flow gullies. In addition gully long profiles on Marsare distinct from generic slope profiles on Mars with some overlap – this shows that the gully forming process hasa marked morphological impact on martian slopes.Our observed latitudinal patterns in gully formation are in agreement with previous investigations [3, 4],with greater numbers of gullies found at∼40° and∼70° latitude north and south. In addition we found that gulliesat mid-latitudes are more densely packed and occur across whole slope sections (rather than isolated patches),suggesting this region has preferential conditions for gully formation. Our morphological comparison with gullieson Earth suggests that the formation process shifts from pure water flow at high latitudes to debris flow processesat lower latitudes. We find more mature gully profiles on pole-facing slopes. These latitudinal and orientationobservations support the Costard [5] climate-based model for gully formation, rather than formation from anunderground aquifer.[1] Kreslavsky M. A. (2008) Workshop on Martian Gullies 2008, #1303, p.54-55. [2] Kirk R. L. et al.(2008) J. Geophys. Res. Planets, 113, doi:10.1029/2007JE003000.[3] Balme M. et al. (2006) J. Geophys.Res.-Planets, 111, doi:10.1029/2005JE002607. [4] Kneissl T. et al. (2009) Earth. Planet. Sci. Lett., In Press. [5]Costard F. et al. (2002) Science, 295, 110-113.

Quantitive analysis of gully long profiles on Earth and Mars

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Quantitive analysis of gully long profiles on Earth and Mars

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