Fig. 4: Plate motions with respect to Antarctica.

Rate (A) and azimuth (B) of motions of Nazca (NZ, green) and South American (SA, purple) plates relative to Antarctica (AN) plate, calculated at the specified coordinates. Motions are calculated by sampling one million times the finite rotations discussed in the main text. Uncertainty ranges are reported at the 95% confidence interval. The NZ/AN motion reconstructed here via the Pacific plate is compatible with the independent inference of changes in NZ/AN spreading rates and azimuth derived from observed cross-ridge magnetic lines as reported by Tebbens et al. (1997, in brown).