News & Views in 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.

Northern peatlands store over 1,000 Gt of carbon, almost double previous estimates, according to a new analysis of peat core data. The fate of this peat carbon, however, is uncertain in a rapidly changing world.

The large domes found on the dwarf planet Ceres may not result from cryovolcanism, but from solid-state flow analogous to salt doming on Earth, according to numerical simulations of gravitational loading.

Wet rice cultivation in the Palu Valley, Indonesia, prepared the ground for the devastating liquefaction-induced landslides that were triggered by the M_w 7.5 earthquake in 2018, suggest two studies of the spatial relationship between landslide morphology and irrigation.

The structure of the lithosphere is key to reconciling the dynamic topography predicted by mantle convection models with residual topography derived from observations, suggest analyses of both models and data.

Subduction processes may have operated very early in Earth’s history according to the heavy silicon isotope compositions of Archaean igneous rocks. The silicon that precipitated out of the Archaean oceans as chert was subducted and melted to yield seawater-like heavy isotope signatures in early granitic rocks.

The distribution of iron-loving elements between the mantles of the Moon and Earth may differ from established belief, suggest two studies that determine the hafnium–tungsten ratio and sulfide–silicate melt partitioning of elements in the lunar mantle.

African savannah grasslands initially proliferated in the late Miocene due to declining atmospheric CO₂, rather than previously proposed regional climate drying. Supplanting previous woodland vegetation due to photosynthetic adaptations, these grasslands set the stage for subsequent mammalian evolutionary trends on the continent.

Ocean-floor plateaus are not voluminous lava flows from central volcanoes as thought, but anomalously thick oceanic crust, suggest magnetic anomaly patterns from the Shatsky Rise, in the northwestern Pacific Ocean.

Earth’s formation by the accretion of volatile-rich carbonaceous chondrite-like materials, without a need for exotic building blocks or secondary volatile loss, is supported by recognition of a plateau pattern for highly volatile elements.

Confidence that banded iron formations record oxic conditions during deposition is established, as a model demonstrates that they are formed of primary iron oxides rather than secondarily altered silicate minerals.

Deep soil carbon in tropical catchments can be rapidly mobilized to rivers upon land-use change to agriculture, suggest analyses of dissolved organic carbon. Such carbon stocks had been thought stable for millennia.

The Toarcian oceanic anoxic event disrupted terrestrial ecosystems as well as the marine realm, according to analyses of microfossils derived from land plants. Changes in diversity and composition were initially more rapid in terrestrial ecosystems.

The Moon’s isotopic composition is uncannily similar to Earth’s. This may be the signature of a magma ocean on Earth at the time of the Moon-forming giant impact, according to numerical simulations.

Nitrogen deposition in China has stabilized over the past decade, thanks to efficient regulation of fertilizer use, suggests an analysis of wet and dry deposition.

Flotation of aerosols as a film on the hydrocarbon lakes of Saturn’s moon Titan may explain the lakes’ stillness, and could influence the atmospheric hydrocarbon cycle.

Pyroclastic density currents generate a basal air cushion that reduces friction with the ground, reveal laboratory experiments. This explains their ability to travel rapidly over large distances from their volcanic source.

Thinning and retreat of Jakobshavn Isbræ has reversed in 2016, in tandem with regional ocean cooling.