* Astronomy

Nine members of the Xtreme Everest team have reached the summit of Cho Oyu and have returned safely to Kathmandu, Nepal. Xtreme Everest is a group of doctors and scientists coordinated by the UCL Centre for Aviation, Space and Extreme studying how the human body functions in extreme environments.

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A 20-member team of British based medicos is preparing to carry out medical lab experiments on the slopes of South Col of Mt Everest, which they said would be the world's highest laboratory.
The medical research team of Xtreme Everest will make the first ever measurements of blood oxygen in the 'death zone', at altitudes above 8,000m where the human body has struggled -and frequently failed to survive-to find out effects on the human body in high altitude.

The team plans to take measurements of oxygen in arterial blood at extreme high altitude above 8,000 metres for the first time. It is anticipated that up to ten members of the team will summit Everest.
The Centre for Aviation, Space and Extreme Environment Medicine (CASE) team of the University College London (UCL) will lead the expedition scheduled for May 2007.
The experts will measure the amount of oxygen in their own blood along with running tests to see how well their brains, lungs and metabolism are working at such extreme altitude. They have asked for 208 volunteers having good level of fitness for the 23-day expedition, Parkinson said. Volunteers desiring to taking part need to pay £2,395, which includes return flights from the UK to Kathmandu and another £500 for scientific research.

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Geologists have learned that the height of the Tibetan Plateau, a vast, elevated region of central Asia sometimes called "the roof of the world," has remained remarkably constant for at least 35 million years.

David Rowley from the University of Chicago and Brian Currie of Miami University in Ohio report their finding in the February 9 issue of the journal Nature.
Before their last expedition to Tibet, the geologists expected to find evidence that the plateau was rising 35 million years ago, the result of large-scale geologic forces grinding India and Asia against one another. They found instead that the plateau has stood at its current high elevation for at least 35 million years.
The best explanation for Rowley and Currie's finding: the plateau has widened progressively northward as the Earth's crust thickened.

"This explanation is at odds with a popular theory that has survived since the 1980s" - Chris Beaumont, geological oceanographer, Dalhousie University in Halifax, Nova Scotia, Canada.

India and Asia began colliding 50 million years ago as a result of plate tectonics, a large-scale geologic force that slowly moves the continents around the Earth's surface. The collision took place in an area that once may have resembled the tropical Indonesian Island of Sumatra, and it produced the Tibetan Plateau. Today, the plateau stretches for 190,000 square miles at an elevation of approximately 16,000 feet.

"It looks not a whole lot different in places from Kansas. You could convince yourself that you're in Kansas, except that you're breathing a little too hard" - David Rowley, Professor and Chairman of the Geophysical Sciences Department at Chicago.

According to a popular theory, both the Earth's crust--the planet's outermost solid layer--and the upper portion of the mantle layer that lies below the crust thicken as the continents collide. Then the crust containing the plateau would have "bobbed up", while the mantle fell away and sank deep into the Earth.
Rowley and Currie's research, which is funded by the National Science Foundation, supports the idea that the collision has deformed the crust, but not the mantle.

"The bottom of the crust is weak and any attempt to increase the elevation increases the stress on the bottom of the crust, and that crust is now capable of flowing" - David Rowley.

The Nature paper is based on a technique that Rowley and a colleague developed in the late 1990s to determine the elevation of ancient land surfaces.

"It turns out that elevation is one of the most sensitive monitors of large-scale processes happening within the Earth" - David Rowley.

The technique relies on precise measurement of oxygen isotopes, different varieties of oxygen atoms that are found in rocks formed at various elevations. Water vapour derived from the oceans displays a well-defined isotopic composition that changes in a predictable way as air masses rise, cool and condense with elevation.
As precipitation seeps into the soil, it becomes incorporated into nodules of calcium carbonate, a chemical compound found in rocks around the world. An oxygen isotopic analysis of these nodules reveals the elevation at which they were created, as Rowley and his University of Chicago colleague Ray Pierrehumbert reported in 2001.
The technique is accurate to within approximately 2,000 feet, and it is especially sensitive at elevations of three to five kilometres.

"For asking questions about the height of the Himalayas, the height of Tibet, the height of the Andes, it's terrific. But if you go to small mountain ranges or small elevation differences, you're probably not going to be able to say much with confidence" - David Rowley.

Previous efforts aimed at reconstructing the elevation history of mountain ranges depended on comparing tree species that live today at various elevations with the species found in the distant past as indicated by fossilized leaves and pollen. But temperature, rainfall and climate change can influence the distribution of tree species, along with elevation.

"It's not always clear which one is the driver" - David Rowley.

As for the Tibetan Plateau, Rowley plans to examine even older rocks to see if he can take a scientific snapshot of the area as it began to rise. From this, scientists will be better able to answer a critical question: how fast does the concentration of heat-generating radioactive elements in thickening crust limit its strength?

"Some people had earlier argued that it took, 10, 20, 30 million years before you got enough heat production to limit that strength" - David Rowley.

"The significance of this research should not be underestimated. It demonstrates how a critical observation has the potential to advance our understanding of continental deformation" - Chris Beaumont.

http://geosci.uchicago.edu/~rowley/

Chinese researchers have discovered that the Tibetan Plateau, dubbed "the roof of the world", is moving northward and eastward at 7 to 30 millimetres a year.

"The plateau is moving because it's being pushed by the Indian plate" - Dr. Tan Kai, researcher with China Seismological Bureau who is collecting data for a global positioning system (GPS) survey.

A collision between the Indian Plate and the Eurasia Continent Plate 40 million years ago shaped the Tibet Plateau and its surrounding geological features.
As the two plates of the earth's crust are still colliding, the plateau is moving north by more than 20 millimetres and is growing taller by several millimetres a year, too.
Dr. Tan and his colleagues have found that Lhasa, on the southern end of the plateau, is moving 30 millimetres a year northeast at an angle of 38 degrees. Meanwhile, the Kunlun Mountains in the central plateau is moving 21 millimetres a year at 61 degrees. The Qilian Mountains further north are moving between 7 to 14 millimetres a year, at an angle of 80 degrees.

"Which means the entire plateau is moving seven to 30 millimetres a year on average. Such moves are barely noticeable and will not change the Chinese continental plate any time soon. But they're still significant from the geological point of view" - Dr. Tan Kai.

The Kunlun mountain range is one of the longest mountain chains in Asia, extending more than 3000 km. It runs along the western border of China southwards beside the Pamir range, then curves to the East, to form the border range of northern Tibet.
The seismological bureau has conducted more than 50 GPS surveys on the Tibetan Plateau since 1991. China has 1,056 survey stations, of which 340 are in neighbouring country Tibet.

The GSP surveys can capture real-time, highly precise data to calculate velocity of the crustal movement. Results of the surveys will help scientists study the formation and evolution of the plateau and evaluate the region's risk of earthquake and other geological disasters.