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TOPIC: Antarctica


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RE: Antarctica
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A group of Washington University researchers will head to Antarctica later this month to learn more about the continent's geologic origins.
The group will install 10 seismographs that will provide data to help other scientists build better climate change models, Douglas Wiens, a Washington University professor and team leader said.

"We have no idea what's beneath the ice. No one has even taken any rock samples. It's thought that when the Earth's climate started to cool millions of years ago, the first glaciers in the world formed in these mountains" - Douglas Wiens.

The team's base camp will be built 250 miles north of the South Pole, in a region of Antarctica that has only been explored by a Russian team 50 years ago and last year by a Chinese group.

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This animation, comprised of images acquired by Envisats Advanced Synthetic Aperture Radar (ASAR) instrument, shows the breaking away of a giant iceberg from the Pine Island Glacier in West Antarctica. Spanning 34 km in length by 20 km in width, the new iceberg covers an area nearly half the size of Greater London.


PLAY (3639KB, gif)

The animation highlights the movement in the area between September 2006 and October 2007. The Pine Island Glacier is visible stretching from the right of the image to the centre. The tongue of Pine Island is shown moving inland between September 2006 and March 2007. Between April and May 2007, the detached iceberg in front of Pine Island moves significantly. Also in May 2007, a crack in Pine Island becomes visible. By October, the new iceberg has completely broken away.
Several different processes can cause an iceberg to form, or calve, such as action from winds and waves, the ice shelf grows too large to support part of itself or a collision with an older iceberg. Since Pine Island Glacier was already floating before it calved, it will not cause any rise in the world sea level.
Iceberg calving like this occurs in Antarctica each year and is part of the natural lifecycle of the ice sheet. A 34-year long study of the glacier has shown that a large iceberg breaks off roughly every 5-10 years. The last event was in 2001.

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The UK is looking to claim sovereignty over a large area of the remote seabed off Antarctica.
The claim for an area around British Antarctica is one of a number being prepared by the Foreign Office, a spokeswoman said.
Even if granted, those rights would not allow Britain to contravene the treaty that prohibits oil and gas tapping under the seabed.
The spokeswoman labelled the move "a safeguard for the future".

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Ashworth Glacier
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A glacier in Antarctica has been named after Allan Ashworth, distinguished professor of geosciences.
Ashworth was notified of the honour in a letter dated Aug. 1 from Wendy Shaw, secretary of the New Zealand Geographic Board. The board has the responsibility for assigning place names in Antarctica.

This glacier falls within the Ross Sea Region of Antarctica, Shaw wrote in the notification, noting that the Ashworth Glacier flows west-southwest from Supporters Range in the Transantarctic Mountains into the Mill Glacier. The naming of this feature honours your significant contribution to science (palaeontology and stratigraphy) in Antarctica.

Ashworth has participated in four research trips to Antarctica.

To become a part of the long line of explorers and scientists who have had Antarctic mountains and glaciers named for them is a high honour. The Ashworth Glacier is a classic alpine tributary glacier located near the Beardmore Glacier and Mill Glacier, which are named after industrialists who supported Sir Ernest Shackletons expedition in 1907 - Dr. Allan Ashworth.

The glacier lies in the area where Ashworth has conducted studies on fossils from the lake deposits that show the transition from Antarcticas warmer and wetter climate millions of years ago to the present situation in which the landscape is permanently frozen.
Ashworth was nominated for the recognition by Jane Francis, professor at the University of Leeds (United Kingdom) Centre for Polar Science.

Allan has made spectacular discoveries at Oliver Bluffs in the Beardmore region, very close to the site of his glacier. At Oliver Bluffs, only 300 miles from the South Pole, he discovered the first fossil beetles and a fossil fly from Antarctica, as well as fossil mosses and seeds that show us that Antarctica was not always the cold, icy place that it is today. Allans work in the Beardmore region, as well as his more recent expeditions to the Dry Valleys, is changing scientists views about the history of glaciation in Antarctica. He has made his mark on Antarctic science and now that is recorded permanently with the glacier named after him - Jane Francis.

Ashworth also serves as chair for the U.S. National Committee for the International Union for Quaternary Research. Ashworths research has been featured in The Scientist, GEO magazine, and on the Web sites, Exploring Antarctica, a multimedia feature of The Washington Post, and Living Antarctica, a documentary film by Anne Aghion.

Source

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Australian scientists have discovered a giant underwater current that is one of the last missing links of a system that connects the world's oceans and helps govern global climate.
New research shows that a current sweeping past Australia's southern island of Tasmania toward the South Atlantic is a previously undetected part of the world climate system's engine-room, said scientist Ken Ridgway.

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Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship

Antarctica is renowned for its extreme cold; yet surprisingly, radar measurements have revealed a vast network of lakes, rivers, and streams several kilometres beneath the Antarctic ice sheet. Sealed from Earth's atmosphere for millions of years, they may provide vital information about microbial evolution, the past climate of the Antarctic, and the formation of ice sheets, among other things. The next stage of exploration requires direct sampling of these aquatic systems. However, if sampling is not done cautiously, the environmental integrity and scientific value of these environments could be compromised. At the request of the National Science Foundation, this National Research Council assesses what is needed to responsibly explore subglacial lakes. The report concludes that it is time for research on subglacial lakes to begin, and this research should be guided by internationally agreed upon protocols. The report suggests an initial protocol, which includes full characterization of the lakes by remote sensing, and minimum standards for biological and other types of contamination.

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Transantarctic Mountains
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The origins of the highest peaks in Antarctica have long been shrouded in mystery. Now researchers suggest they are remnants of a gigantic high plateau that collapsed as the Earth tore apart.
The frozen continent of Antarctica was the last explored by humanity. The mysteries lurking at its heart inspired the pioneering horror writer H.P. Lovecraft to imagine "Mountains of Madness" there in the 1930s higher than the Himalayas, "pylons of a frightful gateway into forbidden spheres of dream, and complex gulfs of remote time, space, and ultra-dimensionality."

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Title: Plateau collapse model for the Transantarctic MountainsWest Antarctic Rift System: Insights from numerical experiments
Authors: Robert W. Bialas et al., Lamont Doherty Earth Observatory of Columbia University, Earth and Environmental Science.

The Transantarctic Mountains are the highest and longest rift-related mountain belt on Earth and divide the Antarctic continent into its eastern and western halves. Despite their prominence, no model has been able to adequately explain their formation or their juxtaposition with the adjacent West Antarctic Rift System, a broad region of thin, extended continental crust exhibiting wide rift characteristics. Bialas et al. explore the possibility that the Transantarctics represent a remnant edge of a high-elevation plateau that has since rifted and subsided to create the West Antarctic Rift System. This concept revolutionizes the thinking about the Transantarctic Mountains. Previous models discuss ways to make the mountains go up; Bialas et al. propose a scenario where the Transantantarctic Mountains were already high, and the adjacent rift system goes down. They use numerical models and geological and geophysical data to back this new theory of Transantarctic Mountain development.

Geological Society of America


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The 3,000-kilometre-long Transantarctic Mountains are a dominant feature of the Antarctic continent, yet up to now scientists have been unable to adequately explain how they formed. In a new study, geologists report that the mountains appear to be the remnant edge of a gigantic high plateau that began stretching and thinning some 105 million years ago, leaving the peaks curving along the edge of a great plain.
This study revolutionises thinking about Antarcticas evolution. Previous studies have discussed ways in which the mountains may have risen; the current study says they were already high long ago, and that the adjacent land sank. After the mountain chain was isolated, its topography, with summits up to 4.5 kilometres high, was accentuated by erosion caused by glaciers.

The Earth Institute at Columbia University

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RE: Antarctica ice sheet
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An ice sheet in Antarctica that is the world's largest with enough water to raise global sea levels by 60 meters (200 feet) is relatively stable and poses no immediate threat to ocean levels, according to new research.
While studies of other ice sheets, like the Greenland and West Antarctic ice sheets, show they are both at risk from global warming, the East Antarctic ice sheet will "need quite a bit of warming" to be affected, Andrew Mackintosh, a senior lecturer at Victoria University, said Wednesday.
The air over the East Antarctic ice sheet, an ice mass more than 3,000 kilometres  across and up to four kilometres  thick centred on the South Pole, will remain cold enough to prevent significant melting in the near future, the New Zealand-led research shows.
But it may eventually become vulnerable to the effects of rising sea levels driven by the melting of other ice sheets, Mackintosh's team found. Their research was published this week in the journal Geology.

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Icebergs
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Icebergs are 'ecological hotspot'
Drifting icebergs are "ecological hotspots" that enable the surrounding waters to absorb an increased volume of carbon dioxide, a study suggests.
US scientists found that minerals released from the melting ice triggered blooms of CO2-absorbing phytoplankton.
The number of icebergs found in waters around Antarctica have increased in recent decades as a result of global warming, the researchers wrote in the paper.

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