Tectonic Processes in Subduction and Arc-Continent Collision

Convergent plate boundaries, where one lithospheric plate descends beneath another, drive subduction and ultimately lead to arc-continent collision. In classical subduction settings, the downgoing oceanic plate transports volatiles into the mantle, triggering partial melting in the overlying mantle wedge and generating volcanic arcs. Forearc regions above the trench accumulate sediments and form accretionary prisms, while back-arc basins may open by trench retreat or slab rollback. When the buoyant continental margin of the subducting plate arrives at the trench, subduction slows or ceases and collision initiates. This process uplifts mountain belts, exumes deep-seated metamorphic rocks, emplaces ophiolitic fragments onto continental crust and reorganises crustal deformation through thrusting, strike-slip faulting and extensional detachments. Slab rollback, tear-off and complex mantle flow further modulate magmatic flux, seismicity and the distribution of mineral resources. Such processes operate globally—in regions from the western Pacific to the Mediterranean—and underpin natural hazards, crustal growth and the localisation of metallogenic provinces.

Research from Nature Portfolio

Recent studies have revealed an exceptionally young supra-subduction zone ophiolite in eastern Indonesia, where fragments of oceanic lithosphere formed above an infant arc-forearc system. Detailed geochronology and geochemistry show a rapid magmatic pulse between 10 and 8 million years ago, with boninitic and tholeiitic compositions indicating melt extraction from a hydrated mantle wedge. This ephemeral ophiolite did not represent pre-existing oceanic crust but rather an upper-plate response at the onset of arc-continent collision. The findings link small, short-lived ocean basins with orogenic ophiolites worldwide and demonstrate how early collision magmatism can be recorded in transient supra-subduction sequences.

Tectonic Processes in Subduction and Arc-Continent Collision publication trend

The graph below shows the total number of articles in tectonic processes in subduction and arc-continent collision across all publications each year (not limited to Nature Index journals).

Technical terms

Subduction: The process by which one tectonic plate sinks beneath another into the mantle at a convergent boundary.

Arc-continent collision: The convergence of an island arc with a continental margin, halting subduction and uplifting mountain belts.

Ophiolite: A section of oceanic crust and upper mantle emplaced onto continental crust during collision.

Supra-subduction zone (SSZ): The region above a subducting plate where specialised magmas, such as boninites, form.

Slab rollback: The retreat of a subduction trench due to the sinking of the subducting plate, often creating back-arc extension.

Slab tear: A rupture or break in a subducting plate that alters local mantle flow and melting regimes.

Forearc: The area between the trench and volcanic arc, commonly housing accretionary prisms and sedimentary basins.

References

1. The ephemeral history of Earth’s youngest supra-subduction zone type ophiolite from Timor. Communications Earth & Environment (2023).
2. Slab segmentation, anomalous arc volcanism, and giant porphyry copper deposits in Indonesia. Earth and Planetary Science Letters (2024).
3. Evidence of Magma Reservoirs Beneath Volcanoes in Northern Sulawesi and the Molucca Sea From Regional Earthquake Tomography. Geophysical Research Letters (2025).