Identifying Olivine Composition in Tyrrhena Terra, Mars, Using Orbital Mid-Infrared Data

Magnificent rock / Crater floors of melted Mars / Hold the olivine

Characterizing the Aqueous Geochemical History at Tyrrhena Terra, Mars

Tyrrhena Terra is an intriguing region of Mars extending from the southern part of Isidis Basin at the Libya Montes southward to Hellas Basin. Noachian and Hesperian basement rocks are covered by Syrtis lavas, especially in the northwestern part of Tyrrhena Terra and the surface is carved by craters and fluvial features. The central region is marked by the craters Jarry-Desloges, Owen, and Briault, and contains abundant Fe/Mg-rich phyllosilicates and olivine-bearing outcrops in Noachian-Hesperian terrain [1,2]. Many of the phyllosilicates in this region are located in crater ejecta and in central crater mounds, consistent with uplift of ancient materials, but some are present in dissected terrains. We are investigating the mineralogy and geology of this region through a coordinated study using TES, THEMIS, CRISM multispectral strips, CTX and HRSC imagery, and HRSC digital elevation models at a regional scale, as well as CRISM targeted images and HiRISE views of the surface at a closer scale. The phyllosilicate spectra across the central Tyrrhena Terra region (see attached figure) are most consistent with chlorite, Fe/Mg-smectite, and mixed smectite-chlorite. A few hydrated silica and zeolite outcrops are also present. This mineralogy is consistent with higher temperature processes than the primarily Fe/Mg-smectite and carbonate spectra observed in the Libya Montes region [3,4]. A few sites towards the east of our study site contain more Fe/Mg-smectite than chlorite and additional hydrated phases including sulfates, which likely represent a different formation environment. Ongoing investigations of the targeted CRISM images at the eastern part of this area are characterizing the stratigraphy of these aqueous units and their association with higher temperature units towards the west and smectite-carbonate units towards the north

The high-resolution map of Oxia Planum, Mars; the landing site of the ExoMars Rosalind Franklin rover mission

This 1:30,000 scale geological map describes Oxia Planum, Mars, the landing site for the ExoMars Rosalind Franklin rover mission. The map represents our current understanding of bedrock units and their relationships prior to Rosalind Franklin’s exploration of this location. The map details 15 bedrock units organised into 6 groups and 7 textural and surficial units. The bedrock units were identified using visible and near-infrared remote sensing datasets. The objectives of this map are (i) to identify where the most astrobiologically relevant rocks are likely to be found, (ii) to show where hypotheses about their geological context (within Oxia Planum and in the wider geological history of Mars) can be tested, (iii) to inform both the long-term (hundreds of metres to ∼1 km) and the short-term (tens of metres) activity planning for rover exploration, and (iv) to allow the samples analysed by the rover to be interpreted within their regional geological context

The geography of Oxia Planum

We present the geography of Oxia Planum, the landing site for the ExoMars 2022 mission. This map provides the planetary science community with a framework to understand this, until recently, unexplored area. The map comprises (1) a mosaic of the panchromatic Context Camera (CTX) Digital Elevation Models (DEM) and Ortho Rectified Images (ORI) controlled to the High Resolution Stereo Camera (HRSC) multiorbit Digital Elevation Models (DEM) and (2) a mosaic of Colour and Stereo Surface Imaging System (CaSSIS) synthetic colour data products, registered to the CTX ORI mosaic. We define a grid of exploration quadrangles (quads) and an informal group of geographic regions to describe Oxia Planum. These regions bridge the scale gap between features observed on large areas (∼100s km2) and the local geography (10s km2) relevant to the Rosalind Franklin rover’s operations in Oxia Planum

Oxia Planum: The Landing Site for the ExoMars “Rosalind Franklin” Rover Mission: Geological Context and Prelanding Interpretation

The European Space Agency (ESA) and Roscosmos ExoMars mission will launch the “Rosalind Franklin” rover in 2022 for a landing on Mars in 2023.The goals of the mission are to search for signs of past and present life on Mars, investigate the water/geochemical environment as a function of depth in the shallow subsurface, and characterize the surface environment. To meet these scientific objectives while minimizing the risk for landing, a 5-year-long landing site selection process was conducted by ESA, during which eight candidate sites were down selected to one: Oxia Planum. Oxia Planum is a 200 km-wide low-relief terrain characterized by hydrous clay-bearing bedrock units located at the southwest margin of Arabia Terra. This region exhibits Noachian-aged terrains. We show in this study that the selected landing site has recorded at least two distinct aqueous environments, both of which occurred during the Noachian: (1) a first phase that led to the deposition and alteration of ∼100 m of layered clay-rich deposits and (2) a second phase of a fluviodeltaic system that postdates the widespread clay-rich layered unit. Rounded isolated buttes that overlie the clay-bearing unit may also be related to aqueous processes. Our study also details the formation of an unaltered mafic-rich dark resistant unit likely of Amazonian age that caps the other units and possibly originated from volcanism. Oxia Planum shows evidence for intense erosion from morphology (inverted features) and crater statistics. Due to these erosional processes, two types of Noachian sedimentary rocks are currently exposed. We also expect rocks at the surface to have been exposed to cosmic bombardment only recently, minimizing organic matter damage

Hypothesis and Implications for the Geological History of Oxia Planum

We discuss what might have happened in Oxia Planum and what the ExoMars rover will tell us about the geological history of Mars