P065-0001
The Noachian Climate of Mars: Overview of Critical Mars System Science Questions

Tuesday, 15 December 2020
Poster
James W Head III1, Robin Wordsworth2, Lionel Wilson3, Mikhail A Kreslavsky4, Ashley Margaret Margaret Palumbo1 and Harry Y McSween Jr5, (1)Brown University, Providence, RI, United States, (2)Harvard University, School of Engineering and Applied Sciences, Cambridge, MA, United States, (3)Lancaster University, Lancaster, United Kingdom, (4)University of California, Santa Cruz, CA, United States, (5)University of Tennessee, Earth & Planetary Sciences, Knoxville, TN, United States
Abstract:
Recent exploration of Mars sets the stage for relevant fundamental questions and research themes. What initial conditions and Pre-Noachian events were inherited by the Noachian?

1) Planetary Origin: Location and growth rates; volatile budget; earliest bombardment history?

2) Crustal Formation & Evolution: Nature of magma ocean, its aftermath; primary/secondary crust formation; associated outgassing history?

3) Geodynamic Evolution & Petrogenetic History: Core formation, ensuing mantle convection patterns; magnetic field; redox state(s), petrogenetic evolution; timing, role of basins.

4) Primary & Secondary Atmospheres: Nature of each, transition, inheritance?

What was the nature and evolution of the Noachian climate?

1) Nature of Ancient Atmosphere & Climate: What were Noachian “ambient conditions”: ‘warm and wet’ or ‘cold and icy’? How did volatile species/quantities change with time; volcanic outgassing, relationship to evolving atmospheric pressure; nature/scale/duration of ambient climate perturbations; losses and influence on Mean Annual Temperature?

2) Candidate Climate Perturbations: Identify perturbations to the ambient atmosphere? Role of seasonal, spin axis/orbital variations, impacts, greenhouse gas input, hydrolysis, clouds, solar variability?

3) Water Cycle: Initial water inventory, changes with time; vertically integrated hydrological cycle; oceans? How was water partitioned (sources, sinks, D/H, loss to space)?

4) Sulfur Cycle: Total S budget, partitioning with time; nature of volcanic S exsolution with evolving atmospheric pressure; S cycle (sources, sinks, evolution); origin of Valles Marineris Interior Layered Deposits?

5) Mineralogy/Geomorphology Evolution & Implications: Causes of phyllosilicate/sulfate diversity of occurrences? Origin of salts/carbonates/silica-rich deposits? Relation to LN-H climate and weathering processes, rates. How are crater degradation and valley network/closed-basin/open-basin lake origin linked to LN-H mineralogy, climate?

6) Formation/Evolution of Life: Evolving paradigms include an ambient ‘cold and icy’ climate with warming perturbations: What strategies/proxies are needed to explore potential biotic environments on extremely cold surfaces above a warmer, wetter, geochemically active ‘Mars underground’?

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