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[Astronuc]

Scientists uncover the mystery of the Atlantic’s missing crust

The maiden voyage of the new NERC royal research ship, RRS James Cook begins today in the Atlantic looking at a gaping hole in the Earth’s crust. On board a team of scientists are set to examine an area of seafloor where ocean crust is missing – leaving the mantle exposed

Dr Bramley Murton of the National Oceanography Centre, Southampton is one of the earth scientists leading this voyage to the middle of the Atlantic Ocean. He says of the expedition, ‘Oceanic crust covers three quarters of the Earth’s surface. Until now we thought it was all created at volcanic ridges that encircle the globe, deep beneath the sea.

‘But recent sounding from the Mid-Atlantic Ridge have shown an anomalous area of several thousand kilometers square where the Earth’s crust appears to be missing. Here a massive tear in the crust reveals the Earth’s interior and exposes mantle on the seafloor. The presence of this tear challenges our entire understanding of how the oceanic crust is formed.’

The scientists, from NOCS and the Universities of Durham and Cardiff set sail from Tenerife on 5th March 2007. The research site lies close to an area called the Fifteen-Twenty Fracture Zone, on the Mid-Atlantic Ridge between the Caribbean and Africa. This ridge is a chain of underwater mountains that run the length of the Atlantic Ocean.

The team will use detailed sonar systems to map the different types of rocks and produce a 3-D model of the seafloor. They will then lower a robotic drilling rig, developed by the British Geological Survey, on to the seafloor where the crust is missing to take samples of the exposed mantle rock. The scientists hope that, after analysis, they will be able to reveal the mystery of the missing crust.

A cruise diary detailing the research and providing updates and video clips will be available as part of the Classroom@Sea initiative which is maintained by the National Oceanography Centre, Southampton

See - http://www.classroomatsea.net/ 

http://www.noc.soton.ac.uk/gg/classroom@sea/JC007/about.html
 
http://www.noc.soton.ac.uk/gg/classroom@sea/JC007/background.html