A new study in Nature Communications reports that subducting slabs can become effectively “stalled” for long periods—not simply due to mantle temperature or plate motion, but because distinct rock assemblages within the downgoing plate alter how the slab interacts with the surrounding mantle. Using geophysical constraints combined with thermodynamic modeling, the researchers argue that slab dynamics depend on whether the slab interior is dominated by hydrated ultramafic lithologies or by comparatively dry basaltic components.

The central finding is that wet harzburgite—an olivine-rich, ultramafic rock—can sustain slab stagnation by promoting hydration-related weakening processes and controlling the timing and location of mineral transformation. In parallel, the team shows that dry basaltic slab assemblages can also contribute to stagnation, but through a different pathway: by limiting certain water-driven reactions while still maintaining a mechanically coherent, slow-moving interface at depth.

According to the authors, the fate of volatiles is the key variable. As the slab descends, pressure and temperature drive phase changes and dehydration reactions. These reactions can either increase or decrease the effective viscosity and friction along plate boundaries, shifting the balance between slab pull and mantle resistance. Where hydration is sustained, water remains available to weaken lithospheric portions that would otherwise become too rigid to decouple.

In the wet harzburgite scenario, dehydration and metamorphic reactions are predicted to sustain zones of reduced strength within the slab, preventing it from sinking efficiently into the lower mantle. This creates a feedback loop: slower descent limits thermal loss, which in turn preserves conditions that keep the weakening processes active.

In the dry basaltic scenario, the model emphasizes that even without abundant water, basaltic mineralogy can maintain mechanical coupling over a broader depth range. The study suggests that dry assemblages may delay the development of decoupling horizons, thereby prolonging stagnation until the slab eventually transitions to a different rheological regime.

The researchers also connect their results to the observed diversity of subduction-zone behavior, where some slabs advance smoothly while others appear to linger at mantle depths. By treating rock composition explicitly rather than assuming uniform slab properties, the work offers a framework for interpreting why similar plate boundary geometries can yield markedly different slab lifetimes.

Crucially, the analysis links mineral stability, dehydration partitioning, and viscosity contrasts into a single physical narrative. This moves slab “stalling” away from a purely geometric explanation and toward a lithology-driven process that can be tested against seismic signatures.

The findings will likely influence how future models incorporate water budgets and rock types in subduction simulations. If validated by geophysical observations, the wet-versus-dry assemblage distinction could become a practical lever for predicting which slabs will stagnate and for how long.

In short, the study portrays slab stagnation as a sustained state maintained by the contrasting rheological effects of hydrated harzburgite and comparatively dry basaltic materials, reshaping our understanding of how deep Earth water and rock chemistry govern plate evolution.

Subject of Research: Subduction zone dynamics and slab stagnation mechanisms

Article Title: Slab stagnation sustained by wet harzburgite and dry basaltic slab assemblages.

Article References: Shi, D., Shen, Y., Zhao, R. et al. Nature Communications (2026). https://doi.org/10.1038/s41467-026-75639-9

Image Credits: AI Generated

DOI: 10.1038/s41467-026-75639-9

Keywords: slab stagnation; subduction; wet harzburgite; dry basaltic assemblage; dehydration; mantle rheology; volatiles; mineral transformations

Naked mole-rats have long puzzled biologists with their striking eusocial structure, where most adults remain reproductively suppressed while a queen controls the colony’s future. Now, a new study identifies a chemical “queen odour” that links social status to endocrine control, revealing a mammalian analogue to insect queen pheromones.

The molecule, termed IPM, is enriched by the queen and acts as the key mediator of reproductive suppression in non-breeding females. When IPM is present, circulating prolactin rises while progesterone is suppressed, locking the colony into a stable reproductive hierarchy characterized by reduced conflict and maintained group cohesion.

Crucially, the team connects this behavioural outcome to the brain. Using multiple approaches—including non-invasive functional ultrasound imaging (fUSI)—they show that IPM provokes strong activation of olfactory neurons and central neural circuits. This provides a neural substrate for how a chemical cue can trigger colony-wide physiological change, rather than relying on social learning or passive association.

The experiments also clarify sensory routing. Ablating olfaction abolishes aggression initiation and lowers prolactin levels, directly tying IPM detection to reproductive suppression. While the findings are consistent with sensing through the main olfactory epithelium, the authors note that the vomeronasal system may still contribute.

Queen removal normally destabilizes colonies, leading to aggression, reproductive competition, prolactin decline, and, in extreme cases, mortality. Yet when IPM is added to queenless bedding, the colony remains stable for months. During this period, fecal progesterone metabolite levels stay low, indicating sustained ovarian quiescence alongside elevated prolactin.

The study also addresses a longstanding paradox: transferring soiled bedding and urine from parent colonies fails to maintain suppression in isolated individuals. The authors propose that IPM’s chemistry helps explain this discrepancy. As a long-chain fatty acid ester with low volatility, IPM may persist within the colony environment but fail to travel effectively over distance or survive transfer pathways that preferentially carry other chemicals.

Comparative work extends beyond naked mole-rats. IPM is detected in breeding females of four additional Fukomys species. Although reproductive suppression mechanisms may differ across species, the presence of a similar queen-linked odorant suggests convergent chemical strategies for managing reproductive skew in eusocial mammals.

Overall, the research reframes reproduction control as a chemosensory-to-endocrine pathway: IPM activates olfactory–hypothalamic signalling, elevating prolactin and inhibiting GnRH release. This “social hormone” model offers a new principle for social evolution—chemical cues can synchronize behaviour and physiology at the scale of an entire mammal colony.

Subject of Research: Reproductive suppression and social hierarchy in eusocial mammals (naked mole-rats and related Fukomys species)

Article Title: A queen odour mediates reproductive suppression in a eusocial mammal

Article References:

Khallaf, M.A., Hart, D.W., Luo, W. et al. A queen odour mediates reproductive suppression in a eusocial mammal.
Nature (2026). https://doi.org/10.1038/s41586-026-10772-5

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s41586-026-10772-5

Keywords: IPM; queen odour; reproductive suppression; prolactin; GnRH; olfaction; eusociality; functional ultrasound imaging; Fukomys

A new study published in Communications Earth & Environment reports that central Tibet’s rugged mountain architecture was not built in a single burst. Instead, it was shaped by long-lived crustal shortening that persisted after a major ocean closed during the Cretaceous period—when the Bangong–Nujiang Ocean shut down and the surrounding plates collided.

The research team, led by Zhang, Liu, Lin, and colleagues, examines how tectonic forces transferred through the region during and after ocean closure. Their central finding is that shortening did not simply end when the ocean vanished. Rather, the continental collision continued to drive deformation well beyond the immediate collision event, helping sustain mountain growth over extended geological time.

To reach this conclusion, the authors combine regional tectonic constraints with structural observations that reflect how stress and strain were distributed through the Tibetan crust. They interpret the evolving patterns of deformation as evidence for sustained compression, including the way different crustal levels responded to continued convergence.

The study frames the Bangong–Nujiang Ocean closure as a pivotal tectonic switch: once the ocean disappeared, the mechanical coupling between continental blocks increased. That change allowed compression to remain effective, promoting ongoing uplift and crustal thickening in central Tibet.

Importantly, the paper links this sustained shortening to the broader development of Tibetan topography. Rather than treating uplift as a short-lived response to a single collisional moment, the results support a scenario in which post-closure tectonics kept feeding the mountain belt for millions of years.

By addressing the timing and persistence of shortening, the work helps refine how geologists explain the thick crust beneath Tibet and the coexistence of active deformation with long-term structural inheritance. The authors suggest that the region’s growth reflects both the closure of an ocean basin and the prolonged geodynamic consequences of that closure.

The findings also carry implications for how future modeling efforts should represent continental collisions. They highlight that plate-tectonic reorganizations can create enduring mechanical conditions, sustaining deformation even after the most dramatic phase of convergence has passed.

With the DOI link and citation tied to the 2026 publication, the study—understood through its title and approach—offers a clear, data-driven narrative: central Tibet’s rise reflects sustained shortening following Cretaceous ocean closure, shaping a mountain system that kept growing long after the ocean was gone.

Subject of Research: Tectonics and mountain growth in central Tibet following the Cretaceous closure of the Bangong–Nujiang Ocean

Article Title: Sustained shortening following Cretaceous Bangong–Nujiang Ocean closure shaped central Tibetan mountain growth.

Article References: Zhang, B., Liu, S., Lin, C. et al. Communications Earth & Environment (2026). https://doi.org/10.1038/s43247-026-03830-3

Image Credits: AI Generated