Fig. 1: Trench-fill sediments and tectonics of South American subduction.

a Sediment thickness in oceans58 and the topography of the Andes. White thick arrows indicate plate velocities. Black thin arrows indicate trench velocities. b Reconstruction of the Juan Fernandez Ridge relative to South America22. Dashed lines represent the paleo-positions of JFR from 60 Ma to present with an interval of 10 Myrs. Thick semi-transparent lines represent ocean currents, with the cold Humboldt Current (or Peru Current) colored with blue and the rest with black. The green arrow indicates the transport direction of trench-fill sediments. c variation of the maximum Andean topography and the thickness of trench-fill sediments with latitude.