Molten rocks under Atlantic Ocean may shed light on break up of continents

March 28th, 2008 - 2:33 pm ICT by admin  

London, March 28 (ANI): Scientists have for the first time explored a huge volume of molten rock frozen into the crust under the Atlantic Ocean, which might gives them a better understanding of what may have happened during the break up of continents.

The group of scientists, who carried out the exploration, was led by Professor Robert White from the University of Cambridge.

The team had developed a new method of seeing through the thick lava flows beneath the seafloor to the sediments and structures beneath.

When a continent breaks apart, it is sometimes accompanied by a massive outburst of volcanic activity due to a ‘hot spot’ in the mantle that lies beneath the 55 mile thick outer skin of the earth.

When the North Atlantic broke open, it produced 12 million cubic miles (510 million cubic kilometers) of molten rock which extended across 300,000 square miles (one million square kilometres). Most of the volcanic rock is now underwater and buried by more recent sediments.

Now, f or the first time, scientists mapped the huge quantities of molten rock in the North Atlantic.

The rock had been injected into the crust of the earth at a depth of 510 miles (1020 kilometres) beneath the surface along the line of the continental breakup 55 million years ago. Using seismic methods, the research team was able to map the layers of lava flows both near the surface and deep into the earth.

There is a considerable controversy at present as to whether the large scale volcanism was caused by abnormally hot mantle deep in the earth (a ‘hot spot’) or whether it was caused by some other means, such as a compositional change in the mantle that mean it could more easily be melted.

The researchers demonstrated that the volcanic activity requires a temperature anomaly, supporting the hot spot model.

Additionally, the scientists hope that a better understanding of what happened 55 million years ago would provide insight into the changes that occur to the atmosphere and biosphere during volcanic activity.

According to Professor White, The increases in global temperatures are thought to have been caused by a massive release of methane from under the seabed. A better understanding of volcanism and the underlying hot spot will help us understand how such activity might have triggered the methane release and subsequent global warming. (ANI)

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