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1. Earth’s mantle composition revealed by mantle plumes

   https://doi.org/10.1038/s43017-023-00467-0  

   Weis, Dominique; Harpp, Karen S; Harrison, Lauren N; Boyet, Maud; Chauvel, Catherine; Farnetani, Cinzia G; Finlayson, Valerie A; Lee, Kanani_K M; Parai, Rita; Shahar, Anat; et al (September 2023, Nature Reviews Earth & Environment)
2. Water storage in cratonic mantle

   https://doi.org/10.1111/ter.12599  

   Chin, Emily J.; Palin, Richard M. (April 2022, Terra nova)
3. Linking lowermost mantle structure, core-mantle boundary heat flux and mantle plume formation

   https://doi.org/10.1016/j.pepi.2018.01.010  

   Li, Mingming; Zhong, Shijie; Olson, Peter (January 2018, Physics of the Earth and Planetary Interiors)
4. Mantle earthquakes in the Himalayan collision zone

   https://doi.org/10.1130/G46378.1  

   Schulte-Pelkum, Vera; Monsalve, Gaspar; Sheehan, Anne F.; Shearer, Peter; Wu, Francis; Rajaure, Sudhir (June 2019, Geology)

   Abstract Earthquakes are known to occur beneath southern Tibet at depths up to ∼95 km. Whether these earthquakes occur within the lower crust thickened in the Himalayan collision or in the mantle is a matter of current debate. Here we compare vertical travel paths expressed as delay times between S and P arrivals for local events to delay times of P-to-S conversions from the Moho in receiver functions. The method removes most of the uncertainty introduced in standard analysis from using velocity models for depth location and migration. We show that deep seismicity in southern Tibet is unequivocally located beneath the Moho in the mantle. Deep seismicity in continental lithosphere occurs under normally ductile conditions and has therefore garnered interest in whether its occurrence is due to particularly cold temperatures or whether other factors are causing embrittlement of ductile material. Eclogitization in the subducting Indian crust has been proposed as a cause for the deep seismicity in this area. Our observation of seismicity in the mantle, falling below rather than within the crustal layer with proposed eclogitization, requires revisiting this concept and favors other embrittlement mechanisms that operate within mantle material. 

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5. The effects of discontinuity topography in the mantle transition zone on global geodynamic observables and mantle heterogeneity

   Glisovic, Petar; Lu, Chang; Forte, Alessandro M. (February 2022, Geophysical journal international)

   Despite progress in tomographic imaging of Earth’s interior, a number of critical questions regarding the large-scale structure and dynamics of the mantle remain outstanding. One of those questions is the impact of phase-boundary undulations on global imaging of mantle heterogeneity and on geodynamic (i.e. convection-related) observables. To address this issue, we developed a joint seismic-geodynamic-mineral physical tomographic inversion procedure that incorporates lateral variations in the depths of the 410- and 660-km discontinuities. This inversion includes S-wave traveltimes, SS precursors that are sensitive to transition-zone topography, geodynamic observables/data (free-air gravity, dynamic surface topography, horizontal divergence of tectonic plates and excess core-mantle boundary ellipticity) and mineral physical constraints on thermal heterogeneity. Compared to joint tomography models that do not include data sensitivity to phase-boundary undulations in the transition zone, the inclusion of 410- and 660-km topography strongly influences the inference of volumetric anomalies in a depth interval that encompasses the transition zone and mid-mantle. It is notable that joint tomography inversions, which include constraints on transition-zone discontinuity topography by seismic and geodynamic data, yield more pronounced density anomalies associated with subduction zones and hotspots. We also find that the inclusion of 410- and 660-km topography may improve the fit to the geodynamic observables, depending on the weights applied to seismic and geodynamic data in the inversions. As a consequence, we find that the amplitude of non-thermal density anomalies required to explain the geodynamic data decreases in most of the mantle. These findings underline the sensitivity of the joint inversions to the inclusion of transition-zone complexity (e.g. phase-boundary topography) and the implications for the inferred non-thermal density anomalies in these depth regions. Finally, we underline that our inferences of 410- and 660-km topography avoid a commonly employed approximation that represents the contribution of volumetric heterogeneity to SS-wave precursor data. Our results suggest that this previously employed correction, based on a priori estimates of uppermantle heterogeneity, might be a significant source of error in estimating the 410- and 660-km topography. 

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