Fig. 5: Plateau uplift by underplating and crustal partial melting.
From: Crustal melting and continent uplift by mafic underplating at convergent boundaries
a East Anatolian Plateau, (b) central Andes Plateau, (c) Tibetan Plateau. Left panels: schematic cross-sections through the three plateaus constrained by regional models with topographic profiles on top. Middle panels in (b), c profile locations. Right panels – 1D crustal density (in g/cm3) models used for calculating the predicted topography (dotted lines with values on the right) from the free air gravity, assuming isostasy with a compensation depth of 80 km and with the Arabian Plate as reference model (middle panel in (a) with 1.0 km topography) (Methods and Supplementary Fig. 8). The predicted elevation for the EAP lithosphere model in Fig. 2c is 1.7 km as observed (a). The elevation of 4.5 km in the Altiplano/Puna Plateau (b) is explained by a lithosphere model with the same densities as for the EAP, similar thickness of the high-velocity lower crust3, and the presence of a felsic partially molten crustal body71. The high topography of the Lhasa block (c) reflects a balance between the degree of lower crust eclogitization11,52,72 and the thickness of the melt-hosting layer inconclusively imaged seismically with two end-member models. Both models explain the observed 5.6 km high topography. Model I2 has a 40 km thick layer (with bulk 2.60 g/cm3) hosting partially molten bodies and a 20 km thick eclogitic lower crust (3.30 g/cm3, with 39–55% eclogitization). Model II11 has a 10 km thick layer with partially molten bodies, above a lower crustal layer with density of 3.15 g/cm3 (15–22% eclogitization).
