December 10, 2008

Scientists record continental displacement

A U.S.-led international team of scientists says it has, for the first time, recorded a geological event that is considered key in shaping the Earth's crust.

Led by Purdue University Professor Eric Calais, the researchers said they measured ground displacements as two African tectonic plates moved apart and molten rock pushed its way toward the surface during the first so-called dyking event ever recorded within the planet's continental crust. Calais said the event left a wall of magma 6 miles long and 5 feet wide wedged between the two plates.

While dyking events have been reported in the thin oceanic crust, they had never been directly observed and quantified in the thicker areas of the planet's shell, Calais said.

The existence of the events provides a key element of how the Earth's rigid outer shell -- the lithosphere -- breaks apart and moves. Although the known forces pushing and pulling on continents are not powerful enough to break them apart, repeated dyking events could severely weaken the lithosphere, allowing it to shift and break under far less force, Calais said.

A paper detailing is to appear this week in the journal Nature.