61-4 Mantle Waves Connect Rifted Margins and Cratonic Interiors

Abstract:

Continental rifting is traditionally viewed as a spatially confined process, with impacts restricted to the rift zone itself. We present a body of work showing how rifting can instead trigger a chain of convective instabilities — "mantle waves" — that propagate hundreds to thousands of kilometres cratonward along the lithospheric root, with consequences persisting for tens to >100 Myr after breakup (Gernon et al., 2023–2026). These 'waves' progressively erode the base of adjacent cratonic keels, driving a sequence of mantle, and in turn, surface responses. The removal of some ~35 km thick keels of cratons promotes small-degree mantle melting, generating volatile-rich kimberlite melts, explaining the multi-million-year lag between supercontinent breakup and kimberlite eruption, and linking diamond-bearing volcanism directly to earlier rift dynamics. This removal of lithospheric keel drives isostatic uplift of craton interiors, coupling rift-flank escarpment retreat to plateau formation in continental interiors. Some of the removed, geochemically enriched keel is entrained into the suboceanic asthenosphere, fuelling ocean island and seamount volcanism even in some cases where mantle plumes are absent. The resulting wave of topographic uplift can further enable the nucleation of continental ice sheets (Abstract #2091183), thus linking rift-driven mantle dynamics to major climate transitions over 100 Myr later. Mantle waves represent a highly systematic physical mechanism through which rifting can reorganise mantle flow, cratonic architecture, and Earth's surface environment long after breakup, extending the reach of rifting processes, and their geologic and climatic implications, far beyond the rift itself.

References

Gernon, T.M., et al., 2026, Continental breakup–driven uplift instigated East Antarctic Ice Sheet formation. Science, doi: 10.1126/science.adz6758.

Gernon, T.M., et al., 2025, Enriched mantle generated through persistent convective erosion of continental roots. Nature Geosci., doi: 10.1038/s41561-025-01843-9.

Gernon, T.M., et al., 2024, Coevolution of craton margins and interiors during continental breakup. Nature, doi: 10.1038/s41586-024-07717-1.

Gernon, T.M., et al., 2023, Rift-induced disruption of cratonic keels drives kimberlite volcanism. Nature, doi: 10.1038/s41586-023-06193-3.

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