Oxia Planum
Oxia Planum was one of eight potential landing sites for the European Space Agency and Roscosmos ExoMars mission. After a five-year-long selection process, it was officially selected to be the landing site for Rosalind Franklin (rover). It met the rover landing criteria based on its latitude, elevation, surface slopes, and its Noachian-aged terrains. It was chosen because of its relatively smooth topography and its abundance of hydrated minerals.
Overview
Oxia Planum contains one of the largest exposures of clay-bearing rocks on Mars. The age of the region was calculated to be from ~3.6 billion years old to ~4 billion years old. The site is iron-magnesium rich clays, indicating that water once played a role here. The site sits in an area of valley systems with the exposed rocks exhibiting different compositions, indicating a variety of deposition and wetting environments. Dark resistant units, named for being dark-toned erosion resistant areas, are spread across the surface of the site. The formation of the dark resistant units is hypothesized to have occurred from either fluvial deposits or by volcanic activity during the Amazonian period. The dark resistant units may have preserved the state of the older stratum beneath it.
Clay accumulation underneath the remnants of a fan or delta near the outlet of Coogoon Vallis may offer preservation for biosignatures against the planet's harsh radiation and oxidation environment.