EARLY NOACHIAN TERRAINS ON MARS: VESTIGES OF THE ORIGIN AND EARLY EVOLUTION OF LIFE?

NASA’s main science goal for exploring Mars is to determine if life ever arose on the red planet and to identify environments conducive to the early development and preservation. In search of evidence to address the question of whether life originated and evolved on Mars, we propose a new strategy targeting the extremely ancient terrains (> 4.0 Ga) that contain distinct magnetic anomalies and relatively large tectonic structures, which include Terra Cimmeria, Terra Sirenum, Arabia Terra, Terra Sabaea, among others. These ancient terrains are distinctly older than those that have been visited thus far by landing, roving, and now hovering spacecraft. They extend further back in martian geologic time than the formation of the giant-four impact basins; Hellas, Isidis, Argyre, and Chryse (if an impact basin). For life to have begun and prospered on Mars, like Earth, requires terrains that contain nutrients sourced from diverse rock types, heat energy, water, and mixing of these components from a hydrological cycle. For life to have persisted through major changing planetary environmental conditions, from a planet with an active dynamo/magnetic field and relatively thick atmosphere (i.e., recorded in the extremely ancient terrains but not those explored to date) to the present-day desert-like surface environment and interacting thin atmosphere, it would likely have required exceptional environmental conditions. In this presentation, we will discuss a new strategy which targets extremely ancient terrains, and the rationale for why the terrains may provide the best opportunity to determine if life ever existed on Mars.