Feeds

Antarctica's amazing disappearing, reappearing ice shelf

It comes and goes, say boffins

Choosing a cloud hosting partner with confidence

The Ross Ice Shelf in Antarctica has melted and reformed many times in geologically recent history, scientists have found.

A research team has spent the last few weeks drilling 600 metres down into the giant ice slab to extract and analyse samples from the seabed below the ice, the BBC reports.

The long term goal of the project is to find out how stable the massive shelf of ice (which is the size of France) is. The clues are in the kinds of sediment they are finding, and they have already established that the shelf is far from a permanent feature.

"When the ice sheet is there, the sediments you get under it are very rubbly. They are the sort of sediments that you would see at the front of [glaciers]," New Zealand Institute of Geological and Nuclear Sciences palaeoclimatologist Dr Tim Naish told the news organisation.

"When the ice lifts a bit so water can flow underneath, and it becomes an ice shelf, you still get those rubbly bits but you also get sediments that tell you water was around, that water was flowing back and forth.

"When the ice shelf disappears and you've got completely open water, then you've got a completely different situation where you have high biological productivity and a lot of microfossils preserved."

The behaviour of the ice shelf is important for at least two reasons.

The shelf acts to buttress the huge Western Antarctica ice sheet. Researchers think if the ice shelf collapses, the loss of ice from the continent of Antarctica would speed up as the glacial flow would have nothing to impede its journey to the ocean.

By dating the sediments, the researchers are also keen to find out if there is a relationship between the coming and going of the ice shelf and fluctuations in the climate. This could help to predict future behaviour of the shelf, and therefore of the ice sheets themselves, and could be vital in predicting future sea-level changes.

Earlier research has shown that fluctuations in the ice shelves are connected with a wobble of the Earth in its orbit around the sun. These so called Milankovitch cycles come approximately every 23,000, 41,000 and 100,000 years.

The team notes that in the past the atmospheric concentrations of carbon dioxide had not risen above 300 parts per million, as they have today. The researchers speculate that this additional carbon in the atmosphere might make a difference to the behaviour of the shelves during the natural Milankovitch cycles. ®

Internet Security Threat Report 2014

More from The Register

next story
MEN: For pity's sake SLEEP with LOTS of WOMEN - and avoid Prostate Cancer
And, um, don't sleep with other men. If that's what worries you
Voyager 1 now EIGHTEEN LIGHT HOURS from home
Almost 20 BEEELION kilometres from Sol
Jim Beam me up, Scotty! WHISKY from SPAAACE returns to Earth
They're insured for $1m, before you thirsty folks make plans
ROGUE SAIL BOAT blocks SPACE STATION PODULE blastoff
Er, we think our ISS launch beats your fishing expedition
Comet Siding Spring revealed as flying molehill
Hiding from this space pimple isn't going to do humanity's reputation any good
BAE points electromagnetic projectile at US Army
Railguns for 'Future fighting vehicle'
OK Google, do I have CANCER?
Company talks up pill that would spot developing tumors
LONG ARM of the SAUR: Brachially gifted dino bone conundrum solved
Deinocheirus mirificus was a bit of a knuckle dragger
prev story

Whitepapers

Cloud and hybrid-cloud data protection for VMware
Learn how quick and easy it is to configure backups and perform restores for VMware environments.
Getting started with customer-focused identity management
Learn why identity is a fundamental requirement to digital growth, and how without it there is no way to identify and engage customers in a meaningful way.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Storage capacity and performance optimization at Mizuno USA
Mizuno USA turn to Tegile storage technology to solve both their SAN and backup issues.
Protecting against web application threats using SSL
SSL encryption can protect server‐to‐server communications, client devices, cloud resources, and other endpoints in order to help prevent the risk of data loss and losing customer trust.