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| Titel |
Landscape evolution reconstructions on Mars: a detailed analysis of lacustrine and fluvial terraces |
| VerfasserIn |
Sandro Rossato, Maurizio Pajola, Emanuele Baratti, Clara Mangili, Marcello Coradini |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250105272
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| Publikation (Nr.) |
 EGU/EGU2015-4760.pdf |
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| Zusammenfassung |
| Liquid water was flowing on the surface of Mars in the past, leaving behind a wide range of
geomorphic features. The ancient major Martian water fluxes vanished about 3.5 Ga.
Meteoritic impacts, wind-erosion, gravity-related phenomena, tectonic deformations and
volcanic activities deeply altered the landforms during the ages. Hence, the reconstruction of
water-shaped landscapes is often complicated.
Fluvial and lacustrine terraces analysis and correlation is a useful approach to understand
and reconstruct the past changes in Martian landscape evolution. These features are
commonly used as reference for the top of water bodies on Earth, since they are void of the
uncertainties or errors deriving from erosional or slumping processes that could have acted
on the valley flanks or in the plateau, where the hydrological network was carved
in.
The study area is located in the western hemisphere of Mars, in the Memnonia
quadrangle, between latitude 9Ë 10’-9Ë 50’South and longitude 167Ë 0’-167Ë 30’ West and it
constitutes a transition region between the southern highlands of Terra Sirenum and the
northern lowlands of Lucus Planum. Many water-shaped features have already been
described near the study area, the most prominent of them being the Ma’adim Vallis and the
Mangala Valles system.
Our results derive from the observations and the analysis of HRSC images (12.5 m spatial
resolution) and Digital Elevation Models (DEMs) derived from the MEX-HRSC (75 m
resolution), that allow the identification of elevation differences up to the tens of meter scale.
We were able to reconstruct six main evolutionary stages of a complex hydrologic systems
consisting of two main palaeorivers (up to 5 km wide) connected one another by a palaeolake
that formed within a meteor crater (~20 km diameter). On the basis of Earth analogs,
these stages/terraces should have evolved during a long period of time, at least
thousands years long. Furthermore, crater counting date back the deactivation of the
system to ca 3.5±0.1 Ga ago, suggesting the presence of a stable environment with
subaerial water fluxes during the Late Hesperian, very close to the liquid-water
disappearance.
Apart from the above mentioned reasons, the increasing interest and ongoing programs of
on-site Martian exploration are additional reasons to study fluviolacustrine depositional
environments. Together with the technology improvements that lead to more flexible safety
constraints for landing/exploring, the possibility to focus on specific and more detailed
scientific aspects is enhanced. |
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