| 1. |
- Carlsson, Ella, et al.
(författare)
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FIELD STUDIES OF GULLIES AND PINGOS ON SVALBARD – A MARTIAN ANALOG.
- 2008
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Ingår i: European Planetary Science Congress, 21-26 September 2008. ; 3
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Konferensbidrag (refereegranskat)abstract
- The gully systems on Mars have been found to superpose young geological surfaces such as dunes and thermal contraction polygons. This in combination with the general absence of superimposed impact craters suggest that the gullies are relatively recent geological formations. The observed gullies display a wide set of morphologies ranging from features seemingly formed by fluvial erosion to others pointing to dry landslide processes. A recent discovery suggests that this is an ongoing process, which appears to occur even today. Several formation mechanisms have been proposed for the Martian gullies, such as liquid carbon dioxide reservoirs, shallow liquid water aquifer, melting ground ice, dry landslide, snow melt and deep liquid water aquifer. However, none of these models can alone explain all the gullies discovered on Mars. So far Martian gullies have been studied only from orbit via remote sensing data. Hydrostatic pingos are perennial ice-cored mounds that may reach an elongated or circular radius of approximately 150 m. They are found in periglacial environments where they are formed by freezing processes in the continuous permafrost. The pingos go through different evolutionary stages as they mature, where the final stage leaves an annular rim left by the collapse of the summit. Images from the High Resolution Imaging Science Experiment (HiRISE) show small fractured mounds in the Martian mid-latitudes. Even though some differences are observed, the best terrestrial analogues for the observed mound morphology are pingos. Gullies and pingos found in Arctic climates on Earth could be an analog for the Martian ones. A comparative analysis might help to understand the formation mechanisms of the Martian pingos and gullies and their possible eroding agent.
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| 2. |
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| 3. |
- Hauber, Ernst, et al.
(författare)
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DEBRIS FLOW FANS AND PERMAFROST LANDFORMS ON SVALBARD (NORWAY): TERRESTRIAL ANALOGUES FOR MARTIAN MID-LATITUDE PERIGLACIAL LANDSCAPES.
- 2010
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Ingår i: 41st Lunar and Planetary Science Conference. ; :1922
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Konferensbidrag (refereegranskat)abstract
- Many young landforms on Mars that were probably formed by exogenic processes show a latitude- dependent geographic distribution. They include surface mantling, lobate debris aprons, lineated valley fill, and concentric crater fill, viscous flow features, gullies, and patterned ground. Collectively, these landforms are hypothesized to represent the surface records of Martian ice ages that were induced by astronomical forcing and associated climate changes. Previous studies often considered just one of the features in isolation (e.g., gullies), without taking into account the geomorphologic context. A more comprehensive investigation of the full assemblage of landforms (landscape analysis), however, has the potential to reduce the ambiguity in interpreting landforms (the problem of equifinality, e.g., in the case of pingos), and to reveal the evolution of the climatic environment in more detail. Here we present permafrost landforms of Svalbard (Norway) as useful terrestrial analogues for the suite of possible periglacial landforms that are typically found at mid-latitudes on Mars. We build on our previous investigations of gullies and fans, and include a number of classical periglacial landforms (patterned ground, rock glaciers, pingos) that all have close morphological analogues on Mars. Based on this comparison, we propose an evolutionary scenario which helps to understand the sequential formation of the Martian landforms into their present state.
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| 4. |
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| 5. |
- Hauber, Ernst, et al.
(författare)
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Landscape evolution in Martian mid-latitude regions: Insights from analogous periglacial landforms in Svalbard.
- 2011
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Ingår i: Geological Society, London, Special Publications. ; 356, s. 111-131
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Tidskriftsartikel (refereegranskat)abstract
- Periglacial landforms on Spitsbergen (Svalbard, Norway) are morphologically similar to landforms on Mars that are probably related to the past and/or present existence of ice at or near the surface. Many of these landforms, such as gullies, debris-flow fans, polygonal terrain, fractured mounds and rock-glacier-like features, are observed in close spatial proximity in mid-latitude craters on Mars. On Svalbard, analogous landforms occur in strikingly similar proximity, which makes them useful study cases to infer the spatial and chronological evolution of Martian coldclimate surface processes. The analysis of the morphological inventory of analogous landforms on Svalbard and Mars allows the processes operating on Mars to be constrained. Different qualitative scenarios of landscape evolution on Mars help to better understand the action of periglacial processes on Mars in the recent past.
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| 6. |
- Hauber, Ernst, et al.
(författare)
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MORPHOMETRY OF ALLUVIAL FANS IN A POLAR DESERT (SVALBARD, NORWAY): IMPLICATIONS FOR INTERPRETING MARTIAN FANS.
- 2009
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Ingår i: 40th Lunar and Planetary Science Conference. ; :1648
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Konferensbidrag (refereegranskat)abstract
- Alluvial fan-like landforms have been identified on Mars. Since alluvial fans are recorders of processes that are sensitive to climatic conditions, the investigation of possible Martian fans can reveal information about the planet`s climate. In lieu of direct observations of active depositional processes on Martian fans, comparisons with terrestrial analogues can constrain models of Martian fan formation derived from remote sensing data. Since present-day Mars is cold and dry, alluvial fans formed in cold deserts should be considered as useful analogues. The probably closest climatic analogue to Mars on Earth are the Antarctic Dry Valleys , but polar deserts can also be found in the Arctic. We report on our field work in summer 2008 and a simultaneous flight campaign with an airborne version (HRSC-AX) of the High Resolution Stereo Camera (HRSC) onboard Mars Express. The results are compared with measurements of Martian fans, based on HRSC DEM.
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| 7. |
- Hauber, Ernst, et al.
(författare)
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Periglacial landscapes on Svalbard: Terrestrial analogs for cold-climate landforms on Mars
- 2011
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Ingår i: The Geological Society of America, Special Paper. - : Geological Society of America. ; 483
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Tidskriftsartikel (refereegranskat)abstract
- We present landforms on Svalbard (Norway) as terrestrial analogs for possible Martian periglacial surface features. While there are closer climatic analogs for Mars, e.g., the Antarctic Dry Valleys, Svalbard has unique advantages that make it a very useful study area. Svalbard is easily accessible and offers a periglacial landscape where many different landforms can be encountered in close spatial proximity. These landforms include thermal contraction cracks, slope stripes, rock glaciers, protalus ramparts, and pingos, all of which have close morphological analogs on Mars. The combination of remotesensing data, in particular images and digital elevation models, with field work is a promising approach in analog studies and facilitates acquisition of fi rst-hand experience with permafrost environments. Based on the morphological ambiguity of certain landforms such as pingos, we recommend that Martian cold-climate landforms should not be investigated in isolation, but as part of a landscape system in a geological context.
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| 8. |
- Hauber, Ernst, et al.
(författare)
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Svalbard (Norway) as a terrestrial analogue for Martian landforms: Results on
- 2009
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Ingår i: EPSC Abstracts. European Planetary Science Congress. ; 4, EPSC2009-772
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Konferensbidrag (refereegranskat)abstract
- Small alluvial fan-like landforms have been observed on Mars in association with recent gullies. Such fans are relatively small (km-scale) when compared to large alluvial fans on Mars, which can reach dimensions of tens of kilometers. The small fans are part of an erosion-transportsedimentation system (alcove-channel-apron). Morphologically very similar systems can be studied on Svalbard (Norway), which is a cold and dry polar desert and, therefore, a potentially useful terrestrial analogue for Mars` climate and climaterelated landforms. Here we give an update on our field work in summer 2008 and a simultaneous flight campaign with an airborne version (HRSCAX) of the High Resolution Stereo Camera (HRSC) onboard Mars Express. We also present very preliminary results from the field campaign in summer 2009.
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| 9. |
- Johnsson, Andreas, 1977, et al.
(författare)
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Evidence for very recent melt-water and debris flow activity in gullies in a young mid-latitude crater on Mars
- 2014
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Ingår i: Icarus. - : Elsevier BV. - 0019-1035 .- 1090-2643. ; 235, s. 37-54
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Tidskriftsartikel (refereegranskat)abstract
- Terrestrial debris flows and their deposits are mainly studied and monitored because of their hazardous nature. On Mars they may serve as geomorphologic indicators of transient liquid water. We compared the morphology of debris flow-like deposits within a young (∼0.2 Ma) mid-latitude crater on Mars with debris flow fans on Svalbard as possible terrestrial analogues. It was our objective to constrain whether dry granular flow or processes related to water-saturation at or close to the surface were responsible for the formation of the deposits within the crater. We found that the morphological attributes of the deposits on Mars are very similar to debris flows in Svalbard and include overlapping terminal lobes, debris tongues and snouts, debris-flow fans, scoured channels with medial deposits (debris plugs), and clearly defined lateral deposits (levées). Furthermore, the interior crater walls display a range of landforms indicating aspect-dependent degradation, ranging from debris flow-dominated pole-facing slopes, to east-and-west-facing single channel gullies and north-facing talus cones (granular flow). Our findings suggest that the debris flows are not related to impact-induced heating and release of meltwater. We further suggest that degradation of a latitude dependent dust-ice mantling unit may only have played a minor role in this youthful terrain. Instead, we propose that the debris flows are mainly formed by melting of very recent snow deposits after the termination of the last Martian ice-age. As such they may represent some of the most recent geomorphological indicators of transient liquid water in the Martian mid-latitudes. The distinct north-south asymmetry in degradation further demonstrates that insolation-controlled slope processes are surprisingly efficient on Mars during the last <1 Myr.
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| 10. |
- Johnsson, Andreas, 1977, et al.
(författare)
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GEOLOGICALLY RECENT DEBRIS FLOWS IN A WELL-PRESERVED IMPACT CRATER, MARS: INSIGHTS FROM TERRESTRIAL ANALOGS IN SPITSBERGEN, SVALBARD.
- 2011
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Ingår i: 42nd Lunar and Planetary Science Conference. ; 42:2541
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Konferensbidrag (refereegranskat)abstract
- Gullies on Mars are known to display a range of different morphologies but typically include an alcove, channel and apron. Several processes have been invoked to explain their genesis ranging from grain flow, debris flow to fluvial erosion with alluvial deposition. Albeit there is a general consensus that the medium involved is water, more attention is now drawn towards the dominant depositional processes of the gully fan formation. The observed range of fan morphologies asks for several depositional mechanisms and likely vary at different sites due to regional and local differences in climate and colluvial source material. Studies indicate that the common mechanism is fluvial deposition in contrast to debris flow dominated fans which have only been documented at three sites. These sites formed debris deposits of apparently fine grained dusty mantle material. Here we report on unusual Martian debris flows in an unnamed southern hemisphere crater which is rich in coarse grained colluvial material that forms well preserved debris flows, debris plugs and levees. It also displays numerous fresh looking rock falls. This raises the following questions: Why does so well-developed debris flows occur here and not in other nearby craters? What role does the coarse colluvial material play in debris flow initiation and development? Here we describe the debris flow morphology and we compare the morphology of debris flow deposits in Svalbard as potential terrestrial analogs. Furthermore, we investigate the sieve-deposition model as an explanation for the unusual morphology of these debris deposits.
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