Volume 12 Issue 12, December 2019

Tectonic tremor may ultimately be caused by in situ fluid overpressure generated by chemical reactions between a subducting slab and the mantle, according to field and microstructural observations of a shear zone.

Different methods for determining global mean temperature change are preferable for different purposes, such as estimating carbon budgets versus consistency with the achievement of the Paris Agreement, argues a Perspective that outlines methodological choices and recommends decision pathways.

Distinct dependence of atmospheric SO₄^2– formation on NO_x levels in haze-fog events is revealed by SO₄^2– production isopleths that are obtained through simulations of atmospheric chemistry with a box model.

Projected responses of plants to rising atmospheric CO₂ concentrations reduce runoff in large parts of the mid-latitudes as bulk canopy water demands grow, suggests an analysis of precipitation partitioning in climate model simulations.

Land management strategies for enhancing soil carbon sequestration need to be tailored to different soil types, depending on how much organic matter is stored in pools of mineral-associated and particulate organic matter, suggests an analysis of soil organic matter across Europe.

Regeneration efficiencies of dissolved iron in the mesopelagic zone vary significantly across the oceans, largely depending on particulate composition, according to in situ mesopelagic experiments.

Isolation of deep water around Antarctica due to surface cooling can explain half of the change in atmospheric CO₂ levels through glacial–interglacial cycles, according to coupled ocean–sea ice and biogeochemical numerical modelling.

Southern Ocean surface waters near Australia emerged as a major source of CO₂ during the last deglaciation due to shifting ecology and circulation, according a proxy record of seawater pH based on boron isotopes covering the past 25,000 years.

The path of the river Nile has been stable for as long as 30 million years, sustained by mantle convection, according to geophysical and geological evidence and geodynamic model simulations.

The Main Himalayan Thrust comprises two fault planes connected by imbricated faults, a structure that impedes convergence, according to an analysis of the distribution and orientation of aftershocks of the 2015 Gorkha earthquake in Nepal.

Volcanoes that typically erupt effusively can generate highly explosive eruptions of basaltic lava under specific temperature and viscosity conditions, suggest crystallization experiments combined with numerical models of magma fragmentation.

Lawsonite dehydration and release of oxidizing fluids could play an important role in sub-arc mantle oxidation in subduction zones, suggest measurements of changing oxygen fugacity in zoned garnets from Sifnos, Greece.

Chemical reactions between slab and mantle rocks may lead to brittle failure where deep episodic tremor occurs in subduction zones, according to field and microstructural observations of a shear zone in New Zealand.

A large, deep reservoir of asthenosphere flows eastward from the Réunion hotspot and interacts with the Indian spreading ridge, suggests seismological imaging.