Next Pangaea will have pieces missing

摘要

THE world's ultimate jigsaw puzzle will be missing a couple of pieces when it is next put together. A Pangaea-like supercontinent is forecast to form in 250 million years, but a new model predicts that superplumes rising from hotspots deep in the Earth's mantle will keep South America and Antarctica from re-merging with the other continents. Supercontinents form, break apart, then form again every few hundred million years. Geophysicists have traced the process back to early in Earth's history by measuring magnetic fields in ancient rocks, and some have attempted to extrapolate from the present motion of the plates the likely shape of the next supercontinent.