by L. Ojha et al., July 20, 2018 in NatureCommunications (open access)
Transport of fine-grained dust is one of the most widespread sedimentary processes occurring on Mars today. In the present climate, eolian abrasion and deflation of rocks are likely the most pervasive and active dust-forming mechanism. Martian dust is globally enriched in S and Cl and has a distinct mean S:Cl ratio. Here we identify a potential source region for Martian dust based on analysis of elemental abundance data …
by ETH Zurich, June 28, 2018 in ScienceDaily
The valley networks of Mars bear a strong resemblance to those found in arid landscapes on Earth. Researchers have been able to demonstrate this using the branching angles of river valley confluences. Based on these observations, they infer that Mars once had a primeval climate in which sporadic heavy precipitation eroded valleys.
by Geological Society of America and in Geology, April 19,2018 in ScienceDaily
.pdf of the article
In early 2017 scientists announced the discovery of possible desiccation cracks in Gale Crater, which was filled by lakes 3.5 billion years ago. Now, a new study has confirmed that these features are indeed desiccation cracks, and reveals fresh details about Mars’ ancient climate.
“We are now confident that these are mudcracks,” explains lead author Nathaniel Stein, a geologist at the California Institute of Technology in Pasadena. Since desiccation mudcracks form only where wet sediment is exposed to air, their position closer to the center of the ancient lake bed rather than the edge also suggests that lake levels rose and fell dramatically over time.
La géologie, une science plus que passionnante … et diverse