Roller-bearing tectonic evolution of the Juan Fernandez microplate

A combined GLORIA sidescan and Hydrosweep multi-narrow-beam sonar survey shows striking evidence for fan-shaped spreading systems, bounding pseudofaults and compression ridges associated with 90° of clockwise rotation of the Juan Fernandez microplate in the past 4 Myr. A quantitative analysis of this evolution suggests that the microplate has rotated as a rigid 'roller bearing' for most of its history, driven at its edges by shear between the surrounding major plates. The remarkable similarity between the Juan Fernandez and Easter microplates, despite their different tectonic settings, suggests that this is a general model for microplate tectonics.