- 10/04/2021 at 2:09 PM #33891Anonymous UserParticipant
Mars did not dry up suddenly
While the Perseverance rover has just landed on Mars, its predecessor Curiosity continues its exploration at the base of Mount Sharp (or Aeolis Mons), a relief of several from in the center of . Using the the ChemCam instrument to observe in detail the craggy rocks of Mount Sharp in the distance, a Franco-American team led by William Rapin, to the from on and (CNRS / Université Toulouse III – Paul Sabatier / CNES) 1, has just discovered that the of March recorded at this place experienced alternations of dry and wetter periods, before drying up about 3 billion years ago.
So far, the probes in had given clues to the mineral composition of the slopes of Mount Sharp, but since , ChemCam made it possible to observe in detail the sedimentary layers, revealing the conditions under which they were formed. And these change radically over the thickness of the explored (a few hundred meters): above lake clays the base of Mount Sharp, wide and tall crisscrossing structures are the sign of the migration of dunes shaped by the , during a long dry climatic episode. Higher, a fine of alternately friable and resistant layers is typical of deposits by a d’ fluvial: it is the return of wetter conditions.
The climate of Mars has therefore probably fluctuated several times at between dry conditions and environments of lakes and rivers, before the general aridity that we know today. During its extended mission, Curiosity would have to climb the foothills of Mount Sharp to drill in these different layers. He will be able to test this model, characterize in more detail past climatic evolutions, and perhaps understand the origin of these major fluctuations.
This work benefited from the support of CNES, the realization of the ChemCam instrument, as well as its piloting alternately with the in the USA.
The research team also includes scientists from two other French laboratories: the Laboratoire de from Lyon: planets, (CNRS / ENS de Lyon / University Lyon 1) and the Planetology and Geodynamics Laboratory (CNRS / University of Nantes / University of Angers).
Alternating Wet and Dry Depositional Environments Recorded in the Stratigraphy of Mt Sharp at Gale Crater, Mars,
William Rapin, Gilles Dromart, David Rubin, Laetitia Le Deit, Nicolas Mangold, Lauren A. Edgar, Olivier Gasnault, Kenneth Herkenhoff, Stéphane Le Mouélic, Ryan B. Anderson, Sylvestre Maurice, Valerie K. Fox, Bethany L. Ehlmann, James L. Dickson, Roger C. Wiens. , 8 avril 2021. DOI: 10.1130/G48519.1
– William Rapin – Chercheur CNRS – william.rapin at irap.omp.eu
– Véronique Etienne – CNRS press officer – veronique.etienne at cnrs.fr
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