Crucial Proof Explains Anomalously Fast Convergence Between India And Asia In Mesozoic
Closure of the Neo-Tethys Sea and the subsequent formation of the Tibetan Plateau is one of the most significant tectonic events on Earth. How the Indian subcontinent drifted northward anomalously rapidly and collided with Asia is an important concern in describing global modifications in tectonics, environment, and ecosystems.
Double subduction of the Neo-Tethys Sea is a leading model in interpreting this anomalous convergence speed. However, no compelling evidence from the entire Himalaya and adjacent areas has been reported before.
Recently, Yang Shun, one Ph.D. pupil at the Institute of Geology and Geophysics (IGG) of the Chinese Academy of Sciences (CAS), under the supervision of Professors. He Yumei and also Jiang Mingming, along with their group of collaborators, reported crucial seismic proof of slab remnants in the present top mantle to support the dual subduction model strongly.
This work was released in Science Advances on August 26th.
The Myanmar area occupies the eastern end of the Indian-Asian collisional system. Due to less reworking from continental collision, it is one ideal place to probe possible slab remnants of dual subduction. Nevertheless, until recently, it was a blank area for seismic observation and structural imaging of the Earth’s inside.
The research team on the structure of Earth’s deep interior at IGG/CAS has introduced seismic ranges in association with the China-Myanmar Geophysical Survey in the Myanmar Orogen (CMGSMO) in Myanmar since 2016. Using information from the novel seismic arrays, the researchers investigated high-resolution upper mantle structures beneath Myanmar.
By compiling seismic tomography and also waveform modeling, the researchers revealed two subparallel subducted slabs preserved in the present top mantle beneath the Neo-Tethyan tectonic regime for the first time.
After comparing the new slab image with information on the time-space distribution of subduction-related magmatism and ophiolites in Myanmar, the scientist researchers concluded that the new proof supports double subduction of the Neo-Tethys Sea. Further geodynamic numerical modeling subsequently described why the slab remnants were kept intact in the top mantle without breaking off and also sinking into the deep.
The study gives convincing, multidisciplinary, geoscientific evidence to consolidate the double subduction model of the Neo-Tethys Ocean.
More information:
Shun Yang et al, Slab remnants beneath the Myanmar terrane evidencing double subduction of the Neo-Tethyan Ocean, Science Advances (2022). DOI: 10.1126/sciadv.abo1027.
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