The oxygenation of Earth’s surface fundamentally reshaped global biogeochemical cycles, and surface oxygen levels have played a critical role in the origin and diversification of metazoans. Stable thallium (Tl) isotope systematics are mechanistically linked to the burial of manganese (Mn) oxides, making the system an effective redox proxy to track free oxygen (O2) levels in the ocean. The Mesoarchean and mid Proterozoic are two critical periods of time in geologic history for the evolution of microbial and complex life.

Most earthquakes occur along plate boundaries and are caused by the repeated accumulation and release of strain in the rocks of tectonic plates moving past one another. However, the same forces driving these interplate earthquakes does not account for intraplate earthquakes, which are located within the interiors of a tectonic plate. The relatively long recurrence intervals between large earthquakes, causal fault locations, and driving mechanisms of intraplate earthquakes present a challenge to understanding their physical mechanisms and the seismic hazard in intraplate regions.

The search for life beyond Earth is a primary goal of NASA, and in our solar system ocean worlds such as Jupiter’s moon Europa are among the most promising targets. Europa has a global outer shell of ice which is likely to be tens of km thick – but also a lower mass meaning pressures and temperatures in the upper ocean below the shell may be similar to Earth’s polar oceans.