1Benjamin Bultel,1,2Jean‐Christophe Viennet,3François Poulet,3John Carter,1Stephanie C. Werner
Journal of Geophysical Research Planets (in Press) Link top Article [https://doi.org/10.1029/2018JE005845]
1 Centre for Earth Evolution and Dynamics (CEED), Department for Geosciences, University of Oslo, Norway Oslo, Norway
1 Laboratoire d’Archéologie Moléculaire et Structurale, CNRS UMR 8220, UPMC – 4 place Jussieu, 75005 Paris and Institut de Minéralogie, Physique des Matériaux et Cosmochimie, IMPMC, Sorbonne Universités, CNRS UMR 7590, Muséum National d’Histoire Naturelle, MNHN, UPMC, IRD UMR 206, Paris, France
1 Institut d’Astrophysique Spatiale, Université Paris‐Sud, Orsay, France
Published by arrangement with John Wiley & Sons
Noachian surfaces on Mars exhibit vertical assemblages of weathering horizons termed as weathering profiles; this indicates that surface water caused alteration of the rocks which required a different, warmer climate than today. Evidence of this early martian climate with CO2 vapor as the main component causing greenhouse warming has been challenged by the lack of carbonate in these profiles. Here we report the analysis of CRISM L‐detector data leading to the detections of carbonates using a spectral signature exclusively attributed to them. The carbonates are collocated with hydroxylated minerals in weathering profiles over the martian surface. The origin of CO2 for the formation of carbonates could be the atmosphere. The widespread distribution of weathering profiles with carbonates over the surface of the planet suggest global interactions between fluids containing carbonate/bicarbonate ions with the surface of Mars in the presence of atmospheric water until around 3.7 billion years ago. Please also see the Supporting Information for a graphical abstract.