Oxia Planum is a 200 km-wide clay-bearing

plain In geography, a plain, commonly known as flatland, is a flat expanse of land that generally does not change much in elevation, and is primarily treeless. Plains occur as lowlands along valleys or at the base of mountains, as coastal plains, and ...

located on the planet of

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

inside the

Oxia Palus quadrangle The Oxia Palus quadrangle is one of a series of list of quadrangles on Mars, 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Oxia Palus quadrangle is also referred to as MC-11 (Mars ...

on the eastern border of Chryse Planitia. The plain lies between the Mawrth Vallis

outflow channel Outflow channels are extremely long, wide swathes of scoured ground on Mars.Carr, M.H. (2006), ''The Surface of Mars''. Cambridge Planetary Science Series, Cambridge University Press. They extend many hundreds of kilometers in length and are typ ...

to the north-east and the Ares Vallis

to the south-west. In 2019, the

International Astronomical Union The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...

Working Group for Planetary System Nomenclature officially approved Oxia Planum as a feature on the surface of Mars (near 18.275°N 335.368°E). 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 The Noachian is a system (stratigraphy), geologic system and early geologic timescale, time period on the planet Mars characterized by high rates of meteorite and asteroid Impact event, impacts and the possible presence of abundant surface water. ...

-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

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...

s, 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

biosignature A biosignature (sometimes called chemical fossil or molecular fossil) is any substance – such as an element, isotope, molecule, or phenomenon – that provides scientific evidence of past or present life on a planet. Measurable ...

s against the planet's harsh radiation and oxidation environment.

Aeolian features

The aeolian features observed on Oxia Planum indicate a changing wind regime. The formation of periodic bedrock ridges (PBRs) is hypothesized to have occurred by exposure from erosion or by wind. The PBRs record the oldest wind period of the region and indicate a north-northeast or south-southeast wind direction. The formation of transverse aeolian ridges (TARs) occurred by wind. The TARs record a second wind period of the region and indicate a northwest or north-northwest to southeast or south-southeast wind direction. Dust devils and windstreaks from the modern wind period indicate a west-northwest to east-southeast and occasionally a north-northeast to south-southwest wind direction.

References

External links

Google Mars zoomable map – centered on the Oxia area

High resolution images
of the Oxia Planum {{Portal bar, Astronomy, Biology, Solar System Oxia Palus quadrangle Plains on Mars Extraterrestrial plateaus

Overview

Aeolian features

See also

References

External links