An ancient rock dredged from the seafloor and studied by the research team. (IMAGE)
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An ancient rock dredged from the seafloor and studied by the research team.
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.
A new analysis of rocks thought to be at least 2.5 billion years old by researchers at the Smithsonian’s National Museum of Natural History helps clarify the chemical history of Earth’s mantle—the geologic layer beneath the planet’s crust. The study, published today in the journal Nature, centered on a group of rocks collected from the seafloor that possessed unusual geochemical properties.
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Tom Kleindinst
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