Methane bursts as a trigger for intermittent lake-forming climates on post-Noachian Mars

Abstract

Lakes existed on Mars later than 3.6 billion years ago, according to sedimentary evidence for deltaic deposition. The observed fluvio-lacustrine deposits suggest that individual lake-forming climates persisted for at least several thousand years (assuming dilute flow). But the lake watersheds' little weathered soils indicate a largely dry climate history, with intermittent runoff events. Here we show that these observational constraints, while inconsistent with many previously-proposed triggers for lake-forming climates, are consistent with a methane burst scenario. In this scenario, chaotic transitions in mean obliquity drive latitudinal shifts in temperature and ice loading that destabilize methane clathrate. Using numerical simulations, we find that outgassed methane can build up to atmospheric levels sufficient for lake forming climates, for past clathrate hydrate stability zone occupancy fractions >0.04. Such occupancy fractions are consistent with methane production by water-rock reactions due to hydrothermal circulation on early Mars. We further estimate that photochemical destruction of atmospheric methane curtails the duration of individual lake-forming climates to less than a million years, consistent with observations. We conclude that methane bursts represent a potential pathway for intermittent excursions to a warm, wet climate state on early Mars.

References in corpus (9)

• Transient reducing greenhouse warming on early Mars
• The Extreme Ultraviolet and X-Ray Sun in Time: High-Energy Evolutionary Tracks of a Solar-Like Star
• Testing the Early Mars H2-CO2 Greenhouse Hypothesis with a 1-D Photochemical Model
• Persistent or repeated surface habitability on Mars during the Late Hesperian - Amazonian
• Climate Cycling on Early Mars Caused by the Carbonate-Silicate Cycle
• Stratigraphy of Aeolis Dorsa, Mars: stratigraphic context of the great river deposits
• On the Spin-axis Dynamics of a Moonless Earth
• Could Cirrus Clouds Have Warmed Early Mars?
• Structure and Dynamics of Cold Water Super-Earths: The Case of Occluded CH4 and its Outgassing

Cited by in corpus (13)

• The geological and climatological case for a warmer and wetter early Mars
• Paleo-Rock-Hosted Life on Earth and the Search on Mars: a Review and Strategy for Exploration
• The environmental effects of very large bolide impacts on early Mars explored with a hierarchy of numerical models
• A nitrogen-rich atmosphere on ancient Mars consistent with isotopic evolution models
• The paradoxes of the Late Hesperian Mars ocean
• Warming Early Mars with Climate Cycling: The Effect of CO2-H2 Collision-induced Absorption
• Internal Structure and CO${}_2$ Reservoirs of Habitable Water-Worlds
• Subsistence of ice-covered lakes during the Hesperian at Gale crater, Mars
• Effect of Mars Atmospheric Loss on Snow Melt Potential in a 3.5-Gyr Mars Climate Evolution Model
• A Probabilistic Case For A Large Missing Carbon Sink On Mars After 3.5 Billion Years Ago
• Impacts of Atmospheric Carbon Species and Stellar Type on Climates of Terrestrial Planets
• Behaviors of Martian CO2-driven dry climate system and conditions for atmospheric collapses
• Geologic Constraints on Early Mars Climate