Tectonic Processes and Lithospheric Evolution at Rifted Margins

Rifted margins mark the transition from continental to oceanic realms and preserve a rich archive of lithospheric deformation, magmatism and sedimentary processes. Initiated by plate divergence, continental lithosphere undergoes progressive thinning through distributed extension, mechanical necking and eventual rupture. This evolution may be accompanied by decompression melting in the mantle, generating magmatic products that range from voluminous flood basalts to discrete underplating events. Rift architecture is governed by crustal inheritance, extension velocity, obliquity of applied strain and thermal structure, leading to a spectrum from magma-rich to magma-poor margins. Hyperextension may exhume subcontinental mantle, whereas magma-dominated break-up produces seaward-dipping volcanic sequences. Post-break-up cooling and subsidence shape passive margin stratigraphy, with implications for sediment routing and hydrocarbon prospectivity. Recent advances in geophysical imaging and numerical simulation have refined our understanding of fault interaction, plume-rift coupling and the conditions that dictate the onset of sustained seafloor spreading. The study of rifted margins thus bridges fundamental plate-tectonic theory with practical concerns in resource exploration, geohazard assessment and the formation of new plate boundaries.

Research from Nature Portfolio

Recent studies have revisited the influence of Large Igneous Provinces on continental break-up, revealing that emplacement may play roles ranging from dominant drivers to passive aligners of rift zones. A new classification frames provinces as “Shirkers,” “Producers” or “Activators” according to their variable impact on lithospheric rupture. Complementing this, high-resolution seismic analyses along southern Atlantic margins demonstrate that seafloor spreading initiated mostly without anomalously hot mantle. Crustal thicknesses along much of the Early Cretaceous rift axis match normal oceanic values, suggesting that thick magmatic layers landward of the ridge require mechanisms other than plume heating, such as lithospheric extension and decompression melting focused by pre-existing structural heterogeneities.

Tectonic Processes and Lithospheric Evolution at Rifted Margins publication trend

The graph below shows the total number of articles in tectonic processes and lithospheric evolution at rifted margins across all publications each year (not limited to Nature Index journals).

Technical terms

Passive margin: A continental margin formed by rifting that subsequently cools and subsides without active plate convergence.

Magmatic underplating: The intrusion and solidification of magma at the base of the crust, often thickening the lower crustal layer.

Large Igneous Province (LIP): A region of extensive flood basalts and sills emplaced over a geologically short interval, often linked to mantle plumes.

Structural inheritance: Pre-existing faults or fabric in the crust and lithosphere that influence subsequent deformation patterns.

Rift obliquity: The angle between the direction of plate extension and the trend of the rift axis, affecting fault orientation and deformation style.

Seaward-dipping reflectors: Volcanic layers imaged seismically that slope away from the continent, characteristic of volcanic rifted margins.

Hyperextension: Extreme thinning of continental lithosphere that brings mantle peridotite to shallow crustal levels before break-up.

Seafloor spreading: The process by which new oceanic crust forms at a divergent plate boundary and moves laterally away.

References

1. Role of Large Igneous Provinces in continental break-up varying from “Shirker” to “Producer”. Communications Earth & Environment (2024).
2. Mantle Anisotropy in NW Namibia From XKS Splitting: Effects of Asthenospheric Flow, Lithospheric Structures, and Magmatic Underplating. Geophysical Research Letters (2023).
3. Ignition of the southern Atlantic seafloor spreading machine without hot-mantle booster. Scientific Reports (2023).
4. Rifted Margins: State of the Art and Future Challenges. Frontiers in Earth Science (2019).
5. Oblique rifting: the rule, not the exception. Solid Earth (SE) (2018).