Geodynamic Processes in the Yarlung Zangbo Suture Zone

The Yarlung Zangbo Suture Zone marks the collision boundary between the Indian and Eurasian plates, recording the closure of the Neo-Tethys Ocean and the subsequent rise of the Tibetan Plateau. Initial subduction of oceanic lithosphere led to the formation and emplacement of ophiolites, accompanied by high-pressure metamorphism at the base of former oceanic plates. Continental forearc extension and crustal shortening operated in tandem, producing complex structural features such as metamorphic soles, foreland basins, thrust duplexes and normal‐fault rifts. The interplay between underthrusting of Indian lithosphere, asthenospheric flow and surface erosion has driven pulses of uplift, denudation and extensional collapse. Key processes include subduction initiation beneath continental margins, melt–peridotite reaction in upwelling asthenosphere, flexural bending of lithospheric blocks under loading, and the development of detachment fault systems that govern ophiolite internal architecture. Together these processes shape not only plateau elevation and relief but also influence drainage reorganisation, seismicity and mineral resource distribution.

Research from Nature Portfolio

Recent studies have constrained the timing and mechanics of subduction initiation beneath south Tibet through detailed geochronology of metamorphic soles. Garnet Lu–Hf ages reveal that north-directed subduction began at least 14 Myr before oceanic forearc spreading, implying a continental upper plate and generic controls on initiation processes. High-density peridotite sampling across a 2 km ophiolitic mantle section demonstrates that vertical depletion in the mantle cannot be explained by decompression alone but requires lateral melt–rock reaction in an upwelling asthenospheric column. Thermodynamic modelling supports a scenario in which melt focusing produces strong vertical compositional gradients, later transferred into the lithospheric mantle by symmetric splitting of the asthenospheric flow. Foundational work on the flexural response of the Lhasa block shows that supra-crustal loading by Indian plate rocks induced flexural bending of the Gangdese belt and development of an adjacent foreland basin, establishing an early symmetric collision architecture that evolved into today’s asymmetrical wedge.

Geodynamic Processes in the Yarlung Zangbo Suture Zone publication trend

The graph below shows the total number of articles in geodynamic processes in the yarlung zangbo suture zone across all publications each year (not limited to Nature Index journals).

Technical terms

Suture zone: A linear belt marking the former boundary between converging tectonic plates, often hosting ophiolites and mélanges.

Ophiolite: Sections of oceanic lithosphere emplaced onto continental margins, comprising mantle peridotite, sheeted dikes and oceanic crust.

Metamorphic sole: A high-pressure, high-temperature rock layer developed at the base of an ophiolite during subduction initiation.

Detachment fault: A low-angle extensional fault that exhumes deep lithospheric blocks and controls architecture of slow-spreading oceanic crust.

Subduction initiation: The onset of one tectonic plate sinking beneath another, requiring specific mechanical and thermal conditions.

Asthenosphere: The ductile, convecting layer of the upper mantle below the lithosphere, source of decompression melting at spreading centres.

References

1. Formation of the Xigaze Metamorphic Sole under Tibetan continental lithosphere reveals generic characteristics of subduction initiation. Communications Earth & Environment (2023).
2. Vertical depletion of ophiolitic mantle reflects melt focusing and interaction in sub-spreading-center asthenosphere. Nature Communications (2022).
3. Flexural bending of southern Tibet in a retro foreland setting. Scientific Reports (2015).
4. An origin of ultraslow spreading ridges for the Yarlung-Tsangpo ophiolites. Fundamental Research (2021).
5. Rift propagation in south Tibet controlled by under-thrusting of India: a case study of the Tangra Yumco graben (south Tibet). Journal of the Geological Society (2023).