SULFATE-BEARING STRATA SEQUENCE EXTENDS EARLY MARS ENVIRONMENTS CONDUCIVE TO PREBIOTIC EVOLUTION
Résumé
Mars sedimentary record dates as far back as 4.3 Ga, perhaps earlier [1], and the early presence of habitable environments is now welldocumented [2]. Yet, much more uncertain is whether early surface conditions were conducive to an independent emergence of life [3,4]. Prebiotic chemistry which may lead to incipient life forms is
thought to be restricted not only to certain limited conditions, but may even require a specific succession
of distinct environmental changes for it to succeed [5]. As such, it differs substantially from more broadly
defined requirements for habitability.
After exploring strata dominated by clay-bearing mudstones in Gale crater, the Curiosity rover reached
the sulfate-bearing unit, which is hundreds of meters thick and represents evidence for a major environmental
transition characteristic of stratified terrains found in other regions across Mars [6]. At this transition data
collected by the rover uncovered a new type of sulfateenriched stratigraphic sequence.
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