Curiosity Rover Explores Stratigraphy of Gale Crater: Finds Multiple
Transitions between Drier and Wetter Climates
Boulder, Colo., USA: Gale Crater’s central sedimentary mound (Aeolis Mons
or, informally, Mount Sharp) is a 5.5-km-tall remnant of the infilling and
erosion of this ancient impact crater. Given its thickness and age, Mount
Sharp preserves one of the best records of early Martian climatic,
hydrological, and sedimentary history.
In this paper, published today in Geology, William Rapin and
colleagues present the first description of key facies in the
sulfate-bearing unit, recently observed in the distance by the rover, and
propose a model for changes in depositional environments.
The basal part of this sedimentary sequence is ahead of the Curiosity rover
traverse and was recently analyzed with unprecedented resolution by the
rover cameras. The telescopic imager of the ChemCam instrument was used
here in particular, and its images show sedimentary structures that reveal
evolution of environments on Mars during the Hesperian age (3.7–2.9 billion
years ago).
Analysis of the structures shows that on top of the ancient lake deposits
currently explored by the rover (Murray formation), vast aeolian deposits
were formed by a dune field during a prolonged dry climatic episode. Yet,
higher up, the stratigraphy reveals the resumption of wetter climatic
conditions.
The climate of Mars appears therefore to have fluctuated several times at
high order between dry conditions and wet conditions in the Hesperian age,
a period during which Mars’ environment is thought to have changed globally
due to the gradual loss of its atmosphere to space.
FEATURED ARTICLE
Alternating wet and dry depositional environments recorded in the
stratigraphy of Mount Sharp at Gale crater, Mars
William Rapin et al., william.rapin@irap.omp.eu, Institut de Recherche en
Astrophysique et Planétologie, Toulouse, France
URL:
https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G48519.1/596028/Alternating-wet-and-dry-depositional-environments
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