Volume 17 Issue 4, April 2024

Advances in seismological observational and modelling techniques are needed to constrain complex lowermost mantle structures and understand their influence on the global dynamics and evolution of Earth’s interior.

Nature Geoscience spoke with Samantha Hansen, a geophysicist at the University of Alabama and Sebastian Rost, a global seismologist at the University of Leeds about the ultralow velocity zones in the lowermost mantle.

Volcanism after large, caldera-forming eruptions is thought to be muted. Exploration of the partially submerged caldera of Santorini reveals that large explosive eruptions have occurred since the caldera formed.

Pollution by per- and polyfluorinated alkyl substances (PFAS) is widespread in global water resources and likely to be underestimated, according to global analysis of available PFAS data.

The Moon’s primordial solidification is believed to have produced a layer of dense ilmenite cumulates beneath the crust. Remnants of this layer have now been detected under the lunar nearside.

Burbankite is a rare sodium carbonate mineral that is easily dissolved away in its host igneous rocks. Its formation and dissolution can help concentrate rare earth elements that are vital for a low-carbon future, as Sam Broom-Fendley explains.

Through the detection of postcursors of shear waves diffracted at the core–mantle boundary, a zone of ultralow seismic velocities has been identified at the base of the mantle beneath the Himalayas. The presence of this zone is probably linked to a subducted slab remnant that is driving mantle flow in the region.

Human activities have altered the production, transport and fate of mud and associated organic carbon, with important implications for global carbon cycling.

Neoproterozoic banded iron formations formed in partially glaciated oceans where iron-rich and oxygenated water masses met, according to ocean modelling.

The presence of an ultralow velocity zone and seismic anisotropy in the lowermost mantle beneath the Himalayas is linked to subducted slab remnants and southwest mantle flow, according to analyses of seismic waves and mantle anisotropy measurements.

Glacier shrinkage intensifies phosphorus limitation but alleviates carbon limitation in glacier-fed streams, according to analyses of resource stoichiometry and microbial metabolism in glacier-fed streams from mountain regions.

Daytime surface ocean warming has large-scale patterns associated with the sea surface temperature front, leading to an afternoon slackening of the front and impacts on surface wind variability.

Evidence for a past large explosive eruption within the Santorini caldera suggests that early stages of silicic caldera cycles can be more hazardous than previously assumed, according to analyses of intra-caldera deposits from the Kameni Volcano.

Global detections of ultralow velocity zones in high-velocity lowermost mantle regions are associated with thermochemical anomalies linked to subducted slabs, according to analysis of SKKKP B-caustic diffractions with anomalous seismic structures in the mantle and outer core.

A global data analysis suggests that a large fraction of surface waters and groundwaters globally have concentrations of per- and polyfluoroalkyl substances (PFAS) that exceed international advisories or national regulations.

A record of lower mantle flow from 50 million years ago is preserved in the Pacific region and provides evidence for past lower mantle deformation, according to seismic anisotropy tomography.

About half of the lower limb of the Atlantic Meridional Overturning Circulation flows east of the Mid-Atlantic Ridge, a pathway steered by wind and not bottom topography, according to hydrographic data, reanalysis and model simulations.

The Moon’s gravity field preserves a record of the overturn of the early lunar mantle and sinking of dense ilmenite-bearing cumulates, according to a comparison of Gravity Recovery and Interior Laboratory gravity data and geodynamic models.