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Sedimentological analyses of martian gullies: The subsurface as the key to the surface

De Haas, T. and Ventra, Dario and Hauber, Ernst and Conway, S. and Kleinhans, M. (2015) Sedimentological analyses of martian gullies: The subsurface as the key to the surface. Icarus, 258, pp. 92-108. Elsevier. DOI: 10.1016/j.icarus.2015.06.017 ISSN 0019-1035

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Official URL: http://www.sciencedirect.com/science/article/pii/S0019103515002614

Abstract

Gullies are among the youngest landforms formed by liquid water on Mars, and therefore of critical importance in resolving the planets most recent hydrologic and climatic history. Water-free sediment flows, debris flows and fluvial flows have all been identified in gullies. These processes require very different amounts of liquid water, and therefore their relative contribution to gully-formation is of key importance for climatic inferences. We show that many gullies dominantly formed by debris flows, based on sedimentological analysis of outcrops in gully-fans in 51 HiRISE images widely distributed over the southern midlatitudes. The great majority (96%) of outcrop exposures in gully-fans fed by catchments which mainly comprise bedrock and thus host boulders, contain sedimentological evidence for debris-flow formation. These exposures contain many randomly distributed large boulders (>1 m) suspended in a finer matrix and in some cases lens-shaped and truncated layering. Such diagnostic features are rare in gully-fan exposures mainly fed by catchments comprising abundant latitude dependent mantle deposits (LDM; a smooth, often meters-thick deposit consisting mainly of ice and dust), wherein boulders are largely absent. These LDM-fed gullies may have formed by fine-grained debris flows, but this cannot be determined from outcrop sedimentology alone because of the lack of boulders in these systems. The fan surface morphology, in contrast to the subsurface, is dominated by secondary, post-depositional, processes, mainly weathering, wind erosion, and ice-dust mantling. These processes have removed or severely reworked the original, primary, debris-flow morphology over time. This explains the controversy between previously published morphometric analyses implying debris-flow formation and observations of gully-fan surfaces, which are often interpreted as the product of fluvial flows because of the absence of surficial debris-flow morphology. The inferred debris-flow origin for many gullies implies limited and ephemeral liquid water during gully-formation.

Item URL in elib:https://elib.dlr.de/100457/
Document Type:Article
Title:Sedimentological analyses of martian gullies: The subsurface as the key to the surface
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
De Haas, T.Faculty of Geosciences, Universiteit Utrecht, Netherlands,UNSPECIFIED
Ventra, DarioFaculty of Geosciences, Universiteit Utrecht, Netherlands,UNSPECIFIED
Hauber, Ernsternst.hauber (at) dlr.deUNSPECIFIED
Conway, S.Dep. of Physical Sciences, The Open University, Milton Keynes, United KingdomUNSPECIFIED
Kleinhans, M.Faculty of Geosciences, Utrecht University, Utrecht, The NetherlandsUNSPECIFIED
Date:2015
Journal or Publication Title:Icarus
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:258
DOI :10.1016/j.icarus.2015.06.017
Page Range:pp. 92-108
Publisher:Elsevier
ISSN:0019-1035
Status:Published
Keywords:Mars, debis flows, water, climate, ice
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Science and Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Erforschung des Weltraums
DLR - Research theme (Project):R - Projekt MARS-EXPRESS / HRSC
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research
Institute of Planetary Research > Planetary Geology
Deposited By: Hauber, Ernst
Deposited On:03 Dec 2015 16:03
Last Modified:06 Sep 2019 15:26

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