| Pre-Noachian | |
|---|---|
 MOLA colorized relief and elevation map of the Hesperia Planum region. Hesperia Planum is considered to show aspects of Mars' geological evolution from the Pre-Noachian to the Noachian periods. It showcases lowlands representing the Pre-Noachian landscape, alongside higher terrain indicative of the Noachian era. | |
| Usage information | |
| Celestial body | Mars |
| Time scale(s) used | Martian Geologic Timescale |
The Pre-Noachian period is a geological system and early time period on Mars marked by intense meteoroid and asteroid impacts, volcanic and tectonic activity, and the potential presence of surface or subsurface water.[1] The era holds significant importance in Mars' history as it witnessed the planet's formation and the shaping of its geological features. However, understanding the Pre-Noachian period remains elusive, as it is the least comprehended among Mars' four geological epochs. Much of the evidence from this period has been obscured by erosion and deposition processes.
During the Pre-Noachian period, the northern hemisphere of Mars developed lowlands, which may have served as reservoirs for ancient Martian water during subsequent epochs. These lowlands likely formed through lava erosion caused by extensive volcanic activity, as the Pre-Noachian period experienced the highest level of volcanic activity among all Martian epochs.[1]
The atmosphere of Mars during the Pre-Noachian period was denser than it is today, containing higher concentrations of carbon dioxide from volcanic and meteorite outgassing. This may have led to a greenhouse effect on Mars and the formation of various minerals, including silicates, iron oxide, sulfates, carbonates, clays, and hydrates, due to intense heat.[2] Meteorite outgassing is believed to have caused water vapor to condense into Mars' atmosphere, eventually precipitating onto the surface and forming oceans during subsequent epochs.[1] Over time, gases trapped by Mars' gravity during the Pre-Noachian period have gradually escaped into space as the planet cooled.[1]
During this era, Mars possessed a distinctive magnetic field, indicating an active core. As magma cooled in the planet's lower layers, it generated metals necessary for the formation of the magnetic field.[3]
- ^ a b c d "The ages of Mars". Mars Express - European Space Agency (ESA). Retrieved 25 March 2024.
- ^ Dyar, M. D. (2013). "Mars mineralogy: A review of current terrestrial analogs and a proposed new framework". Planetary and Space Science. 86: 27–35. doi:10.1016/j.pss.2013.05.003.
- ^ Halliday, A. J.; Nimmo, F.; Wilson, M. J. R.; Anbar, A. D. (2010). "Mars: Evidence for a Dry Climate from Recent Mass Balance of Atmosphere and Ice". Earth and Planetary Science Letters. 294 (3–4): 538–546. doi:10.1016/j.epsl.2009.12.041.