Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Under the sea

31.03.2008
Scientists explore huge volume of molten rock now frozen into the crust under the ocean’s floor

For the first time scientists have mapped the layers of once molten rock that lie beneath the edges of the Atlantic Ocean and measure over eight miles thick in some locations.

The research, reported in this week’s edition of Nature, gives us a better understanding of what may have happened during the break up of continents to form new mid-ocean ridges. The same volcanic activity in the North Atlantic may also have caused the subsequent release of massive volumes of greenhouse gases which led to a spike in global temperatures 55 million years ago.

The scientists, led by Professor Robert White, FRS at the University of Cambridge, also developed a new method of seeing through the thick lava flows beneath the seafloor to the sediments and structures beneath. The technique is now being employed to further oil exploration of the area which was previously restricted by the inability to image through the lava flows.

When a continent breaks apart, as Greenland and Northwest Europe did 55 million years ago, 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 1–2 million cubic miles (5–10 million cubic kilometres) 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. However the edge of this huge volcanic region is visible on land in a few places including the Giant’s Causeway in Northern Ireland.

For 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 5–10 miles (10–20 kilometres) beneath the surface along the line of the continental breakup 55 million years ago. Using seismic methods, they were 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 demonstrate in this paper 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 will also provide insight into the changes that occur to the atmosphere and biosphere during volcanic activity.

Professor White said: “At the time of the break-up of the North Atlantic 55 million years ago there was a very sudden increase in global temperatures: in fact the earth has never been as hot since then, although the global warming that humans are now causing is likely to take the earth back to the same high temperatures as existed for a short period then”

“The increases in global temperatures are thought to have been caused by a massive release of methane from under the seabed – methane is almost 25 times worse than carbon dioxide as a greenhouse gas. 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.”

The researchers’ findings also have implications for oil exploration in the region. Large volumes of oil have already been discovered (and are being extracted) in the sediments under the seabed between the Shetland Islands and the Faroe Islands. If these same sediments extend westward towards the Faroe Islands, as geological models suggest they do, there may be a lot more oil to be found.

However, because the sediments had thick layers of lava flows (molten rock) poured over them at the time the north Atlantic broke open, conventional exploration techniques have not been able to see through the lavas because they reflect the seismic energy. The scientists succeeded in developing a method of seeing through these thick lava flows to the sediments and structures that lie beneath them.

Genevieve Maul | EurekAlert!
Further information:
http://www.cam.ac.uk

More articles from Earth Sciences:

nachricht New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland
19.01.2017 | University of Gothenburg

nachricht Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>