Long-term drying of Mars by sequestration of ocean-scale volumes of water in the crust

• DOI: 10.1126/science.abc7717
• Publication Date: 2021-03-16T16:12:46Z
• Authors: E. L. Scheller; B. L. Ehlmann; Renyu Hu; D. J. Adams; Y. L. Yung
• Keywords: 550; 13. Climate action; 0103 physical sciences; 01 natural sciences; 520

Geological evidence shows that ancient Mars had large volumes of liquid water. Models past hydrogen escape to space, calibrated with observations the current rate, cannot explain present-day deuterium-to-hydrogen isotope ratio (D/H). We simulated volcanic degassing, atmospheric escape, and crustal hydration on Mars, incorporating observational constraints from spacecraft, rovers, meteorites. found water equivalent a 100 1500 meter global layer are simultaneously compatible geological evidence, loss rate estimates, D/H measurements. In our model, volume participating in hydrological cycle decreased by 40 95% over Noachian period (~3.7 billion 4.1 years ago), reaching values ~3.0 ago. Between 30 99% martian was sequestered through hydration, demonstrating irreversible chemical weathering can increase aridity terrestrial planets.