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Scientists drill deep through Earth's crust off Costa Rica

posted 27 Dec 2012, 13:07 by Mpelembe Admin   [ updated 27 Dec 2012, 13:08 ]

Scientists on a deep-sea drilling ship explore the Earth's deep crust off Costa Rica in search of clues under the Pacific Ocean to explain volcano and earthquake phenomena in the region.

PUNTARENASCOSTA RICA (REUTERS) - Scientists on a deep-sea drilling expedition off the coast of Costa Rica have ventured into the Earth's own unexplored frontier, retrieving rock and gas samples deep within the planet's crust that experts say could answer some of science's biggest questions about the origins and workings of the Earth.

On board the JOIDES Resolution drillship, dozens of scientists and technicians are working on drilling deep into the planet to sample primitive magmatic rocks of the lower crust in the Pacific Ocean.

The waters near Costa Rica -- where the crust is thinnest and the mantle not as deeply buried-- are an ideal location for the expedition. Some areas of the Pacific are also opened by faults which allows for lower crustal rocks, allowing scientists to easily obtain samples on the seafloor.

University of Victoria scientist Kathryn M. Gillis said the expedition's findings could potentially reveal new insights on the planet's inner workings.

"In order to have a good understanding of geological processing we first have to understand the basics, the foundations of how the earth works. And so this is going to enable us to understand how the ocean crust gets formed and then evolves. Now underneath Costa Rica the subduction zone is bringing ocean crusts beneath Costa Rica so we're learning first how the ocean crust gets generated, and what we call a mid-ocean ridge, and then later gets transformed and subducted underneath continents," she said.

With a 4.4-kilometre (two-mile) drill on deck, the elite scientists will attempt to retrieve the deepest rock samples ever extracted from beneath the sea floor to analyse the manufacturing process of the oceanic crust and how the planet handles heat.

"Ok, so we're going to be going from Costa Rica about 2,000 kilometres (1242 miles) to the west near the equator and we're going to be drilling samples that in their earlier life used to reside about four kilometres below the seafloor. And so special geology has brought these rocks to the Earth's floor and we're going to drill through about four and half kilometres of water into these rocks that form very deep in the Earth and our goal of the cruise is to understand how the floor of the ocean gets built over time," added Gillis.

By forming new insights into the formation and structure of the Earth's crust, experts hope to get a better understanding of how the process impacts the tectonic plate movement that sets off earthquake and volcanic activity across the planet.

"We learn about how it was formed, what's happened since it has been formed and have an understanding of the Earth's processes that occur and have a better understanding of our Earth in general and how it might affect, for instance here in Costa Rica, earthquake history, why we have earthquakes, what frequency we have them and also affecting on land the volcanism," said scientist Lisa Mark.

Costa Rica is located along the Pacific Ring of Fire, an area where a large number of earthquakes and volcanic eruptions occur deep in the basin of the Pacific Ocean.

In September, the movement of tectonic plates in the Pacific seismic belt sparked a 7.6-magnitude quake in Costa Rica, damaging historic buildings and many homes.

Earlier this year, authorities in Costa Rica were on alert after the towering Turrialba volcano started spewing clouds of ash and smoke over communities. Turrialba is one of the world's most active volcanos, with a reported five large explosions in the last 3500 years.

Scientists on the JOIDES Resolution are scheduled to continue their deep-water exploration of the Pacific floor until February 2013 before revealing their findings.


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