Integrated perspectives on Noachian martian crust

The Noachian crust of Mars records fundamental planet formation processes that occurred ~4.5-3.6 billion years ago, as well as later water-rock-gas-ice reactions. Similarly aged crust on Earth has been affected by deformation and metamorphism via plate tectonics a process that is only known to be active on one terrestrial planet: Earth. Noachian crust formed through volcanic and impact-driven processes similar to those that operated on Earth during the Hadean and early Archean, and which are likely common processes in the early stages of terrestrial planet formation. Understanding how the Noachian crust formed will therefore increase our understanding of how terrestrial planets form in general, and how they are altered in the absence of plate tectonics. Hydrated minerals in Noachian crust also record water-rock environments that may have been habitable, and could record evidence for past martian life. Water could also be extracted from these hydrated minerals, as well as from ice in Noachian crust, in order to support human inhabitation of Mars. Finally, the Noachian crust could support extant Earth-like martian life in the presence of groundwater with temperatures from -20 122 C. We present a model of the physical structure and chemical/mineralogical properties of Noachian crust by synthesizing observations from martian meteorites, orbital gravimetry, magnetometry, visible wavelength images, as well as gamma ray, visible-to-near-infrared, and infrared spectroscopy. Using this baseline model, we evaluate the value of studying the Noachian crust for understanding planetary evolution, astrobiology, and space resources. Major knowledge gaps can be closed by NASAs Mars 2020 Perseverance Rover, as well as by future missions to explore the martian subsurface, and via discovery of new Noachian-aged martian meteorites.