Correction to: Nature Geoscience https://doi.org/10.1038/s41561-024-01535-w, published online 30 September 2024.
Correction to: Nature Geoscience https://doi.org/10.1038/s41561-024-01535-w, published online 30 September 2024.
Correction to: Nature Geoscience https://doi.org/10.1038/ngeo2916, published online 20 March 2017.
Geological records indicate that the surface of ancient Mars harboured substantial volumes of liquid water, a resource gradually diminished by processes such as the chemical alteration of crustal materials by hydration and atmospheric escape. However, how a relatively warm climate existed on early Mars to support liquid water under a fainter young Sun is debated. Greenhouse gases such as H2 in a CO2-rich atmosphere could have contributed to warming through collision-induced absorption, but whether sufficient H2 was available to sustain warming remains unclear. Here we use a combined climate and photochemical model to simulate how atmospheric chemistry on early Mars responded to water–rock reactions and climate variations, as constrained by existing observations. We find that H2 outgassing from crustal hydration and oxidation, supplemented by transient volcanic activity, could have generated sufficient H2 fluxes to transiently foster warm, humid climates. We estimate that Mars experienced episodic warm periods of an integrated duration of ~40 million years, with each event lasting ≥105 years, consistent with the formation timescale of valley networks. Declining atmospheric CO2 via surface oxidant sinks or variations in the planet’s axial tilt could have led to abrupt shifts in the planet’s redox state and transition to a CO-dominated atmosphere and cold climate.
Forecasting the onset, evolution and end of volcanic eruptions relies on interpretation of monitoring data—particularly seismic signals, such as persistent volcanic tremor—in relation to causative magmatic processes. Petrology helps establish such links retrospectively but typically lacks the required temporal resolution to directly relate to geophysical data. Here we report major and volatile element compositions of glass from volcanic ash continuously sampled throughout the 2021 Tajogaite eruption of Cumbre Vieja volcano, La Palma, Canary Islands. The data reveal the evolving chemistry of melts supplied from depth at a daily temporal resolution. Erupted melt compositions become progressively more primitive until the tenth week of activity, but a sharp reversal of this trend then marks the decline of mantle magma supply and a precursory signal to the eruption end. We find that melt SiO2 content is positively correlated with the amplitude of narrow-band volcanic tremor. Tremor characteristics, inferences from simulations and model calculations point to melt viscosity-controlled degassing dynamics generating variations in tremor amplitude. Our results show promise for a monitoring and forecasting tool capable of quickly identifying rejuvenated and waning phases of volcanic eruptions and illustrate how subtle changes in melt composition may translate to large shifts in geophysical signals.