Ancient Rock from Seafloor

The studied rocks were collected from the Gakkel Ridge near the North Pole and the Southwest Indian Ridge between Africa and Antarctica, two of the slowest-spreading tectonic plate boundaries in the world. The slow pace of the spreading at these ocean ridges means that they are relatively quiet, volcanically speaking, compared to faster-spreading ridges that are peppered with volcanoes such as the East Pacific Rise. This means that rocks collected from these slow-spreading ridges are more likely to be samples of the mantle itself.