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TOPIC: The Earth


L

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RE: The Earth
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A sliver of four-billion-year-old sea floor has offered a glimpse into the inner workings of an adolescent Earth.
The baked and twisted rocks, now part of Greenland, show the earliest evidence of plate tectonics, colossal movements of the planet's outer shell.
Until now, researchers were unable to say when the process, which explains how oceans and continents form, began.
The unique find, described in the journal Science, shows the movements started soon after the planet formed.

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L

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Oldest chunk of Earth's crust ever found
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The oldest known chunk of Earth’s crust has been found in Greenland, and dates back at least 3.8 billion years. The substantial rock is an important find, because it is a type known as ophiolite – a signature of tectonic plate movement – and provides the best evidence yet that continental drift had been going on for at least a billion years longer than thought.

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-- Edited by Blobrana at 22:14, 2007-03-22

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L

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New Ocean Floor
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A multidisciplinary research team from six institutions has for the first time successfully measured a seafloor eruption at its source along the global mid-ocean ridge, the most active volcanic system on Earth. The event along the East Pacific Rise has provided researchers from Woods Hole Oceanographic Institution (WHOI) with a rare opportunity to observe what happens in the immediate aftermath of an eruption.
Ocean-bottom seismometers, which had been deployed by researchers from the Lamont-Doherty Earth Observatory (LDEO) of Columbia University, detected steadily increasing levels of earthquake activity over several years leading up to 2006. Research teams from WHOI and other institutions then used towed cameras and the submersible Alvin to make a visual confirmation of the seafloor eruptions, which decimated the well-studied communities of tubeworms, mussels, and other unique organisms that had been living at the hydrothermal vents in the area.
A research paper describing the seismic data was authored by Maya Tolstoy of LDEO and includes scientists from WHOI, the University of Hawaii, Brown University, the University of Washington, the University of Florida, and NOAA’s Pacific Marine Environmental Laboratory (PMEL). The findings will be published in an upcoming issue of Science, though a preliminary analysis was released on 23 November 2006 on the Science Express web site.

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L

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Europe
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This mosaic of Europe was produced using 143 images acquired by Envisat’s onboard Advanced Synthetic Aperture Radar (ASAR) instrument, working in wide swath medium resolution (WSM) mode, between January and May 2006.
White and greyish spots on the mosaic indicate urban cities, with Paris, London, Dublin, Berlin, Lisbon, Vienna and Madrid being particularly evident. Mountain ranges, including the Alps, Apennines and Pyrénées, are also visible, as is Mount Etna.
The Earth observation Grid team of ESA’s Grid Processing on Demand department produced the mosaic in just 18 hours due to the ability of the Grid-based system to distribute the processing load over many computers.
Of Envisat’s 10 onboard instruments, ASAR is the largest. It was built to provide continuity with the Synthetic Aperture Radar (SAR) sensors, which contributed to major scientific achievements, onboard ESA’s ERS-1 and ERS-2 satellites.

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L

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RE: The Earth
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JC007: Drilling the Mid-Atlantic Ridge
A team of British scientists set sail on Monday to examine why a huge chunk of the earth's crust is missing, deep under the Atlantic Ocean -- a phenomenon that challenges conventional ideas about how the earth works.
The 20-strong team aims to survey an area some 3,000 to 4,000 metres deep where the mantle -- the deep interior of the earth normally covered by a crust kilometres thick -- is exposed on the sea floor.

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Cardiff University scientists will shortly set sail (March 5) to investigate a startling discovery in the depths of the Atlantic.
Scientists have discovered a large area thousands of square kilometres in extent in the middle of the Atlantic where the Earth’s crust appears to be missing. Instead, the mantle - the deep interior of the Earth, normally covered by crust many kilometres thick - is exposed on the seafloor, 3000m below the surface.

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Scientists are to sail to the mid-Atlantic to examine a massive "open wound" on the Earth's surface.
Dr Chris MacLeod, from Cardiff University, said the Earth's crust appeared to be completely missing in an area thousands of kilometres across.
The hole in the crust is midway between the Cape Verde Islands and the Caribbean, on the Mid-Atlantic Ridge.
The team will survey the area, up to 5km (3 miles) under the surface, from ocean research vessel RRS James Cook.
The ship is on its inaugural voyage after being named in February.
Dr MacLeod said the hole in the Earth's crust was not unique, but was recognised as one of the most significant.
He said it was an "open wound on the surface of the Earth", where the oceanic crust, usually 6-7km thick, was simply not there.

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Underground ocean
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A giant blob of water the size of the Arctic Ocean has been discovered hundreds of miles beneath eastern Asia, scientists report.
Researchers found the underground "ocean" while scanning seismic waves as they passed through Earth's interior.
But nobody will be exploring this sea by submarine. The water is locked in moisture-containing rocks 700 to 1,400 kilometres beneath the surface.

ocean-asia_big
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L

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RE: The Earth
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A seismologist at Washington University in St. Louis has made the first 3-D model of seismic wave damping — diminishing — deep in the Earth's mantle and has revealed the existence of an underground water reservoir at least the volume of the Arctic Ocean.
It is the first evidence for water existing in the Earth's deep mantle.
Michael E. Wysession, Ph.D., Washington University professor of earth and planetary sciences in Arts & Sciences, working with former graduate student Jesse Lawrence (now at the University of California, San Diego), analysed 80,000 shear waves from more than 600,000 seismograms and found a large area in Earth's lower mantle beneath eastern Asia where water is damping out, or attenuating, seismic waves from earthquakes.

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L

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The Earth's crust
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New data shakes accepted models of collisions of the Earth's crust
New research findings may help refine the accepted models used by earth scientists over the past 30 years to describe the ways in which continents clash to form the Earth's landscape.
Eric Calais, an associate professor of geophysics at Purdue University, in collaboration with Ming Wang and Zenghang Shen from the Institute for Geology and Earthquake Science in China, used global positioning systems to record the precise movements of hundreds of points on the continent of Asia over a 10-year period.

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IMAGE (3.5mb, 1800 x 1603)

-- Edited by Blobrana at 12:35, 2007-02-08

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