Influence of the asthenosphere on earth dynamics and evolution.

The existence of a thin, weak asthenospheric layer beneath Earth's lithospheric plates is consistent with existing geological and geophysical constraints, including Pleistocene glacio-isostatic adjustment, modeling of gravity anomalies, studies of seismic anisotropy, and post-seismic rebound. Mantle convection models suggest that a pronounced weak zone beneath the upper thermal boundary layer (lithosphere) may be essential to the plate tectonic style of convection found on Earth. The asthenosphere is likely related to partial melting and the presence of water in the sub-lithospheric mantle, further implying that the long-term evolution of the Earth may be controlled by thermal regulation and volatile recycling that maintain a geotherm that approaches the wet mantle solidus at asthenospheric depths.

Great Oxidation and Lomagundi events linked by deep cycling and enhanced degassing of carbon.

For approximately the first 2 billion years of Earth history, atmospheric oxygen levels were extremely low. It wasn't until at least half a billion years after the evolution of oxygenic photosynthesis, perhaps as early as 3 billion years ago, that oxygen rose to appreciable levels during the Great Oxidation event. Shortly after, marine carbonates experienced a large positive spike in carbon isotope ratios known as the Lomagundi event.

Different Is More: The Value of Finding an Inhabited Planet That Is Far from Earth2.0.

The search for an inhabited planet, beyond our own, is a driver of planetary exploration in our solar system and beyond. Using information from our own planet to inform search strategies allows for a targeted search. It is, however, worth considering some span in the strategy and in expectation.