FOR GEOLOGISTS WHO TRY TO UNDERSTAND THE WAY THE EARTH GENERATES its crust, Pito Deep, a submarine canyon near Easter Island, exposes a phenomenal treasure of rock outcroppings that were key parts of the volcanic process of earth-building.
In February, Kathy Gillis—one such geologist (and the director of the School of Earth and Ocean Sciences)—joined a research voyage to Pito Deep led by Duke University’s Jeff Karson.
The site is part of the East Pacific Rise, a mid-ocean ridge that’s spreading at the geologically “super fast” rate of 144 mm a year. A fortunate result of that speedy process is that in the last three million years it has exposed the conduits that brought molten rock towards the sea floor. Normally those geologically important rocks would be embedded a kilometre or so below the floor.
Gillis and graduate student Kerri Heft sent back the above image of one conduit, or sheeted dike. The photo includes an arm of the research submarine “Alvin” as it takes samples, about 3.6 km below the surface.
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