Scientists reveal mechanics of continental break-up

Using seismic data and sophisticated computer simulations, a team of international scientists has revealed the underlying mechanics when a pair of continents part ways -- a phenomenon that is still not completely understood.

The team used computer simulations to uncover a distinct two-phase separation process.

At first, continents gradually inch apart as a hot, jagged rift is etched into the landscape.

Then, after millions of years of strained, relentless pulling of the Earth's crust, the continents lurch away from each other, beginning their steady march towards separate sides of the globe as a new ocean forms between them.

According to the study, published in the journal Nature, this work highlights a phenomenon that is otherwise difficult to explain within the conventional framework of plate tectonics.

"Plates tend to shift around quite slowly because they're sitting on an otherwise very viscous mantle," said study co-author Dietmar Muller from the University of Sydney.

"However, throughout Earth's history, there have been plenty of instances where plates have suddenly sped up during supercontinent breakup. This has puzzled us for decades, as this behaviour can't easily be reconciled with our understanding of what drives plate motion," he added.

The study involved analysis of thousands of kilometres of seismic profiles to pinpoint areas where the continents had been vigorously stretched during their detachment. The researchers then designed computer simulations that independently verified this two-phase breakup.

The split did not tend to end amicably.

"The breakup process leads to margin segmentation, where rapid subsidence, high heat flow and enhanced volcanism characterise the outer margin," said study lead author Sascha Brune from the University of Potsdam, Germany.

It results in a full-margin rupture that sends the outer rims of the continents plunging into the sea.

"The Earth's submerged continental shelves play an indelible role in biogeochemical cycles such as carbon burial and nutrient cycling," Brune said.

--IANS

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