Scientists discover natural deep earth pump that’s crucial in quake formationJune 19th, 2009 - 2:44 pm ICT by ANI
Washington, June 19 (ANI): Scientists have discovered the presence of a natural deep earth pump that is a crucial element in the formation of ore deposits and earthquakes.
The process, called creep cavitation, involves fluid being pumped through pores in deformed rock in mid-crustal sheer zones, which are approximately 15 km below the Earth’s surface.
The fluid transfer through the middle crust also plays a key role in tectonic plate movement and mantle degassing.
The discovery was made by examining one millimetre sized cubes of exposed rock in Alice Springs, which was deformed around 320 million years ago during a period of natural mountain formation.
The evidence is described in a paper published in the latest edition of the journal Nature.
One of the paper’s author’s CSIRO Exploration and Mining scientist Dr Rob Hough said that this was the first direct observation of fluids moving through the mid-crustal shear zone.
“We are seeing the direct evidence for one of the processes that got ore forming fluids moving up from the mantle to the shallow crust to form the ore deposits we mine today, it is also one of the mechanisms that can lead to earthquakes in the middle crust,” Dr Hough said.
Research leader Dr Florian Fusseis, from the University of Western Australia, said that the discovery could provide valuable information in understanding how earthquakes are formed.
“While we understand reasonably well why earthquakes happen in general, due to stress build-up caused by motions of tectonic plates, the triggering of earthquakes is much more complex,” Dr Fusseis said.
“To understand the ‘where’ and ‘when’ of earthquakes, the ‘how’ needs to be understood first. We know that earthquakes nucleate by failure on a small part of a shear zone,” he added.
Dr Fusseis said that while their sample did not record an earthquake, it gave them an insight into the structures that could be very small and localized precursors of seismic failure planes. (ANI)
Tags: alice springs, cavitation, csiro exploration, direct evidence, earthquakes, first direct observation, journal nature, mantle, middle crust, millimetre, mountain formation, nature one, ore deposits, pores, research leader, shallow crust, shear zone, sized cubes, tectonic plates, university of western australia