Volume 13 Issue 4, April 2020

Whether Earth’s water was delivered early or late in its formation is debated. The composition of Venus’s atmosphere may indicate that late accretion, the final stage of planet formation, delivered little water to the terrestrial planets.

Mars’s mantle is chemically heterogeneous and contains multiple primordial water reservoirs, according to an analysis of the hydrogen isotopic composition of minerals in Martian meteorites.

Venus’s atmospheric composition suggests limited water delivery to the terrestrial planets by late accretion, according to numerical simulations of the interior and atmospheric evolution of Venus under various late accretion scenarios.

High-precision measurements suggest that the Earth and Moon have distinct oxygen isotope compositions. This implies distinct oxygen isotopic compositions of the proto-Earth and its impactor that were not fully homogenized by the Moon-forming impact.

Antarctic sea-ice loss causes enhanced warming in the eastern equatorial Pacific, and together with Arctic sea-ice loss accounts for 20–30% of projected warming and rainfall changes in the tropics, suggest climate model simulations.

Thioarsenates are found in the pore waters of rice paddy fields, comparable in concentration to methylated oxyarsenates, according to field, mesocosm and soil incubation studies.

The interface between riverbed and aquifer is a biogeochemical reaction hotspot for arsenic release from river sediments, according to numerical simulations of groundwater flow and biogeochemical reaction processes.

Early Neoproterozoic marine productivity fell due to nutrient drawdown following a switch from an iron-rich to a sulfide-rich ocean, according to records of phosphorus geochemistry measured from sedimentary sections in North China.

The oceans probably remained well-oxygenated for millions of years after the Palaeoproterozoic Lomagundi–Jatuli Event, according to high concentrations and isotope signatures of redox-sensitive metals in the 2-billion-year-old Zaonega Formation, Russia.

Fluid-mediated reaction fronts in rocks can propagate up to 10 centimetres per year, according to a transport model informed by observations of an ophiolite in Norway.

Low-angle normal faults in the Banda Sea have caused large earthquakes that indirectly generated tsunamis due to earthquake-triggered submarine slumping, according to an analysis of historical earthquake and tsunami events and GPS observations.

Tsunami generation by megathrust earthquakes is enhanced by extensional faulting in the upper plate when the subducting slab shallows, according to numerical modelling and observations from the Sumatra–Andaman and Tohoku earthquake–tsunami events.