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Seasonal changes of small-scale polygons near the Martian south pole

van Gasselt, S. and Reiss, D. and Neukum, G. (2004) Seasonal changes of small-scale polygons near the Martian south pole. European Geosciences Union, I General Assembly, Nice, France, 25 - 30 April 2004. ISSN 1607-7962.

Full text not available from this repository.

Abstract

North and south of 30°N/S latitude a belt of ~40° with morphologies resembling terrestrial analogues in periglacial environments can be observed in high resolution imagery of the Mars Orbiter Camera. Among them, the small–scale polygonal features have a striking resemblance with ice–wedge polygons in terrestrial permafrost regions. Nevertheless, their formation could not be unambiguously attributed to thermal contraction only and formation by e.g. desiccation has been proposed alternatively. The fresh appearance of polygon troughs, the low relief, seasonal CO2 frost infill as well as the absence of impact craters on the surface imply a recent formation and recent changes in their morphology. Seasonal observations near the south pole show a pattern of fissures in two subsequent Martian years which show major differences in their crack pattern. These data suggest thermal contraction cracking within a seasonal uppermost layer. The reactivation of older crack patterns and the development of higher–degree–racks as seen on Earth seem to be of minor importance. This observation strongly discourages the idea of subsurface ice wedges underneath these prominent fissure networks in several regions of the southern pole and might be due to seasonal surficial thermal contraction only. Below ~75°S the stability of liquid water and therefore thawing of the upper layer, is still questionable and modeling has been performed on a large scale only (Haberle et al., JGR, 2001). However, local thawing processes cannot be ruled out completely within troughs or in the vicinity of dunes, where temperatures and pressures my reach required values for thawing within the active layer. Still thermal contraction processes based on CO2 could be an alternative without analogues in terrestrial earth sciences.

Item URL in elib:https://elib.dlr.de/10955/
Document Type:Conference or Workshop Item (Speech)
Additional Information: LIDO-Berichtsjahr=2004,
Title:Seasonal changes of small-scale polygons near the Martian south pole
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
van Gasselt, S.Remote Sensing of the Earth and Planets, Institute for Geosciences, FU Berlin, GermanyUNSPECIFIEDUNSPECIFIED
Reiss, D.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Neukum, G.Remote Sensing of the Earth and Planets, Institute for Geosciences, FU Berlin, Germany,UNSPECIFIEDUNSPECIFIED
Date:2004
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Volume:6
Page Range:06267
Series Name:Geophysical Research Abstracts
ISSN:1607-7962
Status:Published
Event Title:European Geosciences Union, I General Assembly, Nice, France, 25 - 30 April 2004
Organizer:EGU
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Space (old)
HGF - Program Themes:W EW - Erforschung des Weltraums
DLR - Research area:Space
DLR - Program:W EW - Erforschung des Weltraums
DLR - Research theme (Project):UNSPECIFIED
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research
Deposited By: Pieth, Susanne
Deposited On:16 Sep 2005
Last Modified:14 Jan 2010 16:34

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