Subduction and collision processes in the Central Andes constrained by converted seismic phases

摘要: The Central Andes are the Earth's highest mountain belt formed by ocean–continent collision1,2. Most of this uplift is thought to have occurred in past 20 Myr, owing mainly thickening continental crust2,3,4,5,6, dominated tectonic shortening7,8,9,10. Here we use P-to-S (compressional-to-shear) converted teleseismic waves observed on several temporary networks image deep structure associated with these processes. We find that Moho (the Mohorovicic discontinuity—generally separate crust from mantle) ranges a depth 75 km under Altiplano plateau 50 km beneath 4-km-high Puna plateau. This relatively thin below such high-elevation region indicates thinning lithospheric mantle may contributed also imaged subducted Nazca oceanic plate down 120 km depth, where it becomes invisible waves, probably completion gabbro–eclogite transformation; direct evidence for presence kinetically delayed metamorphic reactions subducting plates. intermediate-depth seismicity stops at as well, suggesting relation transformation. see an intracrustal low-velocity zone, 10–20 km thick, entire and plateaux, which interpret zone continuing metamorphism partial melting decouples upper-crustal imbrication lower-crustal thickening.