 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
Slippery Stretching Explains Ocean Floor Formation
Leeds, UK (SPX) Jul 31, 2006 For the first time, scientists have found regions of the earth's crust which are stretching apart to form new sea floor; their findings are published in Nature today (27 July). Most new ocean floor is made when undersea volcanic activity splits the crust and molten rock fills the gaps. However some new ocean floor develops when rock stretches along gently inclined tectonic faults called detachment faults. The new research suggests the significance of this stretching process as a way of creating new sea floor has been underestimated. No active examples of these detachment faults had been seen - until now. Co-author Prof Joe Cann, from the University of Leeds said: "Detachment faults appear to break one of the most fundamental rules of geology. After all of the theorising about them, trying to explain how they might exist, it is immensely exciting to discover active faults emerging from the sea floor." Detachment faults are characterised by their curved surfaces, like corrugated iron roofs, and by swarms of tiny earthquakes. Because the distinctive shape of the faults as they emerge, it was possible to show that along 80 kilometres of the Mid-Atlantic Ridge all of the new crust along one side was being formed through a chain of linked detachment faults each at a different stage of evolution, which was highly unexpected. After a while, each fault becomes inactive, and is replaced by a newly-emerging fault. Co-author Deborah Smith, of Woods Hole Oceanographic Institution, said: "In our area, detachment faulting is the most important way in which new ocean floor is constructed. The initial signs are that detachment faulting is far commoner along many hundreds of kilometres of the Mid-Atlantic Ridge than anyone had supposed before. These observations shed a new light on the evolution of the ocean floor." About 3 square kilometres of new ocean floor is created around the world every year. With sea floor comprising two thirds of the Earth's crust, this new work is invaluable in helping us understand how the Earth's surface is formed. Widespread active detachment faulting and core complex formation near 13 degrees N on the Mid-Atlantic Ridge by Deborah Smith of Woods Hole Oceanographic Institution, USA, Johnson Cann of the University of Leeds, UK and Javier Escartin of Marine Geosciences Group, France, was published today (27 July) in Nature. Community Email This Article Comment On This Article Related Links University of Leeds Dirt, rocks and all the stuff we stand on firmly
UV Radiation Causes 60,000 Deaths A Year
London (UPI) Jul 27, 2006The World Health Organization based in Switzerland estimates 60,000 people die each year from spending too much time in the sun. In a report on disease caused by ultraviolet radiation, the WHO says malignant melanoma is responsible for 48,000 deaths while other skin cancers cause the remaining 12,000 deaths, the BBC reports. |
|
|
| The content herein, unless otherwise known to be public domain, are Copyright 1995-2006 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA PortalReports are copyright European Space Agency. All NASA sourced material is public domain. Additionalcopyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement |
