Robots to Help Explain Underwater Volcano Growth

Posted by Joshua S. Hill

May 15, 2008

The history of Earth’s tectonic plates is a fascinating one, and worth study. As they are pulled apart by forces in the Earth, rocks from deep within the mantle are pulled up to fill in the gap left behind. As they rise, the rocks start to melt and subsequently form thousands of volcanoes on the sea floor. Over time, the volcanoes cluster together and form giant ridges.

One of the most significant and largest of these ridges is the Mid-Atlantic Ridge. A divergent tectonic plate boundary it runs for about 10,000 miles (16,000 kilometers) from the Arctic Ocean to near the southern tip of Africa. The MAR separates the Eurasian Plate with the North American Plate in the North Atlantic, and the African Plate from the South American Plate in the South Atlantic.

Now, scientists from Durham University plan to use robots in an expedition to study the growth of underwater volcanoes. Sailing about Britain’s Royal Research Ship James Cook, an international team of 12 scientists will depart from Ponta Delgada, San Miguel, in the Azores, on Friday May 23.

The five week expedition will send explorer robots to map individual volcanoes along the MAR, almost three kilometers below the surface of the sea. But while the peaks of these volcanoes reach to these heights, their flanks descend an additional five kilometers.

After the explorer robots have finished their work, they will then use a robot called ISIS to collect rock samples from the volcanoes. These rock samples will be dated using radiometric dating and by measuring the changing strength of the Earth’s magnetic field through time by studying the natural magnetism of the rocks themselves.

Principal investigator Professor Roger Searle, in the Department of Earth Sciences, at Durham University, said: “The problem is that we don’t know how fast these volcanoes form or if they all come from melting the same piece of mantle rock.

“The ridges may form quickly, perhaps in just 10,000 years (about the time since the end of the last Ice Age) with hundreds of thousands of years inactivity before the next one forms, or they may take half-a-million years to form, the most recent having begun before the rise of modern humans.

“Understanding the processes forming the crust is important, because the whole ocean floor, some 60 per cent of the Earth’s surface, has been recycled and re-formed many times over the Earth’s history.”

In addition to Searle, his team of scientists will include members from the National Oceanography Centre, Southampton, the Open University, the University of Paris and several institutions in the USA.

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