Earth sciences: Ocean crust formation

Eugene (USA), 28 March: The upwelling mantle that lies under the Earth’s crust at mid-ocean ridges is not symmetrical, a paper in this week’s Nature suggests. The surprising find helps refine our understanding of how the oceanic crust is formed.

New oceanic crust is produced at geologically active areas called mid-ocean ridges, where molten rock wells up and solidifies. Using seismic waves to image the mantle underneath one of these regions, Douglas R. Toomey and colleagues find that the zone of upwelling is unexpectedly skewed with respect to the axis of the ridge itself, and they suggest that this may govern segmentation of the East Pacific Rise — a long north–south region of seafloor spreading under the eastern Pacific Ocean.