Tectonic Dynamics and Magmatic Processes in the Indian Ocean

The Indian Ocean constitutes a complex mosaic of mid-ocean ridges, diffuse plate boundaries, intraplate deformation zones and plume-related volcanic provinces. Oceanic spreading along the Central and Southeast Indian Ridges has driven lithospheric accretion since the Late Jurassic–Early Cretaceous breakup of Gondwana. Mantle plumes, most notably the Kerguelen hotspot, have produced large igneous provinces and anomalously thick crust, while intraplate stresses in regions such as the Wharton Basin give rise to diffuse deformation and great earthquakes. Continental rifting off western Australia, the subsidence history of the Bay of Bengal seafloor and the development of nascent shear zones further exemplify the diversity of tectonic regimes. Magmatic processes range from decompression melting beneath spreading axes to enriched subcontinental sources yielding flood basalts and intrusive complexes. Seismic and geophysical imaging have refined models of lithosphere–asthenosphere structure, indicating variable lithospheric thickness, widespread serpentinisation and fluid-mediated weakening. High-resolution bathymetry and gravity data reveal an unexpectedly rugged seafloor with abundant fracture-zone fabrics and seamounts that record past spreading kinematics and modern mass-wasting. Collectively, these insights illuminate the interplay between mantle dynamics, plate motions and surface expressions of volcanism and deformation, with implications for seismic hazard, resource exploration and plate-tectonic evolution.

Research from Nature Portfolio

Recent geochronological work on volcanic rocks linked to the Kerguelen mantle plume has refined eruption ages to a ~147–124 Ma interval, identifying major magma pulses at around 141 Ma and 133 Ma that coincide with successive stages of eastern Gondwana breakup and the initial opening of the Indian Ocean. Zircon dating coupled with geochemical and palaeomagnetic data confirm substantial plume involvement in generating large igneous provinces and in facilitating continental separation. High-resolution seismic reflection profiles across the Wharton Basin reveal a bilayered lithospheric deformation regime: an upper, fluid-filled, serpentinised layer down to ~25 km depth and a lower, intact brittle mantle layer extending to ~45 km where great intraplate earthquakes nucleate. These findings refine models of intraplate seismogenesis and demonstrate how hydration and fracturing modulate lithospheric strength and seismic hazard.

Tectonic Dynamics and Magmatic Processes in the Indian Ocean publication trend

The graph below shows the total number of articles in tectonic dynamics and magmatic processes in the indian ocean across all publications each year (not limited to Nature Index journals).

Technical terms

Mantle plume: Upwelling of anomalously hot, buoyant mantle material that drives large igneous province formation and crustal uplift.

Serpentinisation: Hydration of peridotite in the oceanic lithospheric mantle to form serpentinite, which lowers rock strength and alters seismic velocities.

Riedel shear system: En echelon arrangement of primary and secondary faults accommodating shear within a deforming plate or diffuse boundary zone.

Pull-apart basin: Depressed crustal segment formed between offset strike-slip faults where local extension leads to subsidence and sediment accumulation.

Lithosphere–Asthenosphere Boundary (LAB): The transition zone between cold, rigid lithospheric plates and the underlying ductile asthenosphere.

Decompression melting: Generation of magma through adiabatic ascent of mantle material across its solidus due to pressure reduction.

Fracture zone: Linear oceanic feature marking past transform faults and offsets in mid-ocean ridge spreading, preserved as gravity and bathymetric lineaments.

References

1. Seismic evidence of a two-layer lithospheric deformation in the Indian Ocean. Nature Communications (2015).
2. Evolution of the Southwest Australian Rifted Continental Margin During Breakup of East Gondwana: Results From International Ocean Discovery Program Expedition 369. Geochemistry Geophysics Geosystems (2020).
3. A complete structural model and kinematic history for distributed deformation in the Wharton Basin. Earth and Planetary Science Letters (2020).
4. Is There a Nascent Plate Boundary in the Northern Indian Ocean?. Geophysical Research Letters (2020).
5. Malaysia Airlines flight MH370 search data reveal geomorphology and seafloor processes in the remote southeast Indian Ocean. Marine Geology (2018).
6. The 2 March 2016 Wharton Basin Mw 7.8 earthquake: High stress drop north‐south strike‐slip rupture in the diffuse oceanic deformation zone between the Indian and Australian Plates. Geophysical Research Letters (2016).
7. Deep structure of the northern Kerguelen Plateau and hotspot-related activity. Geophysical Journal International (1995).