Key points are not available for this paper at this time.
Abstract The Himalayan-Tibetan system is growing upward and outward, influenced by mid-lower crustal melting and flow. This study offers a missing geochemical perspective on current geophysics, linking mid-crustal melting beneath SE Tibet to the initiation of transcurrent tectonics that have facilitated the ongoing southeastward extrusion of the Tibetan plateau. New zircon U-Pb data reveal a pulse of Miocene felsic magmatism southeast of the Eastern Himalayan Syntaxis. These have high SiO2, variable but low ɛHf(t) and high δ18O which strongly suggest metasedimentary anatexis. Moderate La/Yb and Sr/Y, with high 87Sr/86Sr(i) and low ɛNd(t) are comparable with mid-lower crust biotite-bearing granitic gneisses. Together with biotite and zircon thermobarometry, these characteristics suggest biotite-dehydration anatexis in the middle crust. Experimental and rheological data suggest melt fractions (> 10%) sufficient to reduce crustal viscosity and allow rheological accommodation for Miocene extrusion of the plateau, and the continued presence of mid-crustal melt is supported by current geophysical data.
Zhu et al. (Mon,) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: