image: The upper plane is the three-dimensional visualizations of the S-wave velocity model, and points mark the ages of exposed post-collisional magmatic rocks. The lower plane is the geodynamic interpretation of Tibetan Plateau growth, which shows the Hoh-Xil Basin in the northern Tibetan Plateau was uplifted by lithospheric mantle removal and subsequent magmatic intrusion.
Credit: ©Science China Press
The Indian-Eurasian continental collision is one of the most spectacular geological events since the Cenozoic, forming the Tibetan Plateau, known as the "roof of the world". The non-uniform latitudinal growth of the Tibetan Plateau has been generally recognized by the temporal-spatial variations of surface uplift in the plateau from massive palaeo-altimetry data. The Hoh-Xil Basin in North Tibet, which was rapidly uplifted in the Early Miocene and accompanied by widespread post-collisional magmatism, is crucial to learn how the Tibetan Plateau has grown northward since the Miocene. However, the key area of the western Hoh-Xil Basin has been poorly covered by seismic stations so far, previous tomographic images did not provide good seismic constraints for the possible deep dynamic processes responsible for plateau uplift and the young magmatism there.
Recently, the National Science Review published a paper on high-resolution imaging of crustal and upper mantle structures beneath the northern Tibetan Plateau, which is collaborative research from Dr. Rizheng He (Chinese Academy of Geological Sciences), Xiaohui Yuan (Deutsches GeoForschungsZentrum GFZ), Dr. Wei Li (China University of Geosciences), and others. The researchers used the recently available data recorded by seismic arrays deployed in the Hoh-Xil Basin to construct a three-dimensional S-wave velocity model via ambient noise tomography. This model exhibits widespread low S-wave velocity anomalies in the crust and uppermost mantle in the northern Tibetan Plateau, which cannot be explained by thermal or compositional effects and therefore require the presence of melts. The correlated crustal and mantle melting imaged in this study is spatially coincident with exposed young magmatic rocks in the Hoh-Xil Basin. So, they proposed that the lithospheric mantle removal induced post-collisional magmatism in the northern Tibetan Plateau. The magmatic accretion and corresponding melting have thickened the crust, promoting the plateau's northward growth.
###
See the article:
Correlated crustal and mantle melting documents proto-Tibetan Plateau growth.
https://doi.org/10.1093/nsr/nwae257
Journal
National Science Review