The Hawaii-Emperor bend
A chain of undersea volcanoes turns a sharp corner, recording a change in how the Pacific plate moves.
- When
- Known to
- ± 1 million years
- Era
- Eocene, Cenozoic
The Emperor Seamounts run north from Hawaii, then bend sharply to run west-northwest as the Hawaiian Ridge. The bend is dated to about 47 million years ago. It was long read as a straightforward change in Pacific plate motion over a fixed hotspot; palaeomagnetic work has since shown the hotspot itself was drifting south beforehand and largely stopped, so the bend records both. Either way it is the clearest kink in the record of plate motion anywhere on Earth, and it coincides with the onset of subduction along the Izu-Bonin-Mariana arc.