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“Wound” in seafloor to be probed
March 2, 2007
Courtesy Cardiff University
and World Science staff
Scientists plan to set sail next week to investigate a startling finding in the depths of the Atlantic: a large area, thousands of square kilometres wide, in the middle of the ocean where the Earth’s crust seems to be missing. A ridge
snaking down the middle of the Atlantic, shown in light-blue
in this ocean floor map, is
an example of a mid-ocean ridge, a place where the Earth's tectonic plates—sections
of the crust—are gradually moving apart. As they do, magma rises up to fill the gap, sometimes leading to submarine volcanic eruptions.
The red area marks a section of the mid-Atlantic ridge where scientists
say crust is mysteriously missing from a wide swatch of the surface,
exposing underlying rock. (Image courtesy GEBCO
)
There, they say, the mantle—a deep layer of Earth, normally buried
under many kilometres (miles) of crust—is exposed on the seafloor, 3
km (1.9 miles) underwater.
It’s “like an open wound on the surface of the Earth,” said T. Chris MacLeod of Cardiff University, U.K. “Was the crust never there? Was it once there but then torn away on huge geological faults? If so, then how and why?”
To answer some of these questions, MacLeod, with a research team led by marine
geophysicist Roger Searle of Durham University, U.K., plans to set off on March 5 for the area, midway between the Cape Verde Islands and the Caribbean.
The voyage is to be the inaugural cruise of a new British research ship, RRS James Cook.
The team plans to image the seafloor using sonar, an instrument that measures distances by emitting sound waves and counting the time they take to reflect off objects and return.
The group also plans to extract rock samples from the seafloor using a robotic drill. These will provide a rare opportunity to learn more about the mantle’s workings, the researchers said.
The expedition’s progress can be monitored via a web link to the ship,
here. The scientists encourage the public, and especially schoolchildren, to ask questions of them during the venture
using the
email link on the website.
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Scientists plan to set sail next week to invest igate a startling finding in the depths of the Atlantic: a large area, thousands of square kilometres wide, in the middle of the ocean where the Earth’s crust seems to be missing. There, the mantle—the deep interior of Earth, normally covered by crust many kilometres (miles) thick—is exposed on the seafloor, 3 km (1.9 miles) underwater. It’s “like an open wound on the surface of the Earth,” said T. Chris MacLeod of Cardiff University, U.K. “Was the crust never there? Was it once there but then torn away on huge geological faults? If so, then how and why?” To answer some of these questions, MacLeod with a team of scientists, led by marine geo physicist Professor Roger Searle of Durham University, U.K., plan to set off on March 5 for the area, midway between the Cape Verde Islands and the Caribbean. The voyage is to be the inaugural cruise of a new U.K. research ship, RRS James Cook. The team plans to image the seafloor using sonar, an instrument that measures distances by emitting sound waves and counting the time they take to reflect off objects and return. The group also plans to take rock samples of the seafloor using a robotic drill. These will provide a rare opportunity to learn more about the mantle’s workings, the researchers said. The expedition’s progress can be monitored via a live web link to the ship, here. The scientists encourage the public, and especially school children, to ask questions of them during the venture via the on-line e-mail link.