UK & World News
Antarctic Lake Drilling Attempt Abandoned
An attempt to melt a borehole through the continental ice sheet to reach a hidden Antarctic lake has been abandoned by a team of British scientists and engineers.
The freshwater Lake Ellsworth, which has been sealed off by the ice 3km (2 miles) down for up to half a million years, could hold life forms not seen before.
But in the early hours of Christmas Day the mission for this Antarctic season ended after running into problems with the drilling.
Professor Martin Siegert, principal investigator, said: "We took the decision to cease our efforts to directly measure and sample Subglacial Lake Ellsworth.
"Although circumstances have not worked out as we would have wished, I am confident that through the huge efforts of the field team, and our colleagues in the UK, we have done as much as we possibly could have done, and I sincerely thank them all."
Drilling stopped after the team was unable to form properly the water-filled cavity 300 metres beneath the ice.
This cavity was to link the main borehole with a secondary borehole used to recirculate drilling water back to the surface.
The delicate drilling operation used water heated to 90 degrees Celsius and pressurised to 2,000 PSI - 20 times more powerful than a car jet-wash.
Engineer Andy Tait, from British Antarctic Survey, said before drilling started: "This will be the deepest borehole ever made this way. It is the most effective way to obtain rapid, clean access to Lake Ellsworth."
The project began 16 years ago and will continue with further attempts to drill though the ice where the team hope to find previously unknown clues to ice and climate history.
Prof Siegert said: "I remain confident that we will unlock the secrets of Lake Ellsworth in coming seasons."
The project statement said: "For reasons that are yet to be determined the team could not establish a link between the two boreholes at 300m depth, despite trying for over 20 hours.
"During this process, hot water seeped into the porous surface layers of ice and was lost.
"The team attempted to replenish this water loss by digging and melting more snow, but their efforts could not compensate.
"The additional time taken to attempt to establish the cavity link significantly depleted the fuel stocks to such a level as to render the remaining operation unviable.
"Reluctantly the team had no option but to discontinue the programme for this season."
Prof Siegert said: "This is of course, hugely frustrating for us, but we have learned a lot this year. By the end the equipment was working well, and much of it has now been fully field tested."
The mission is a consortium of the British Antarctic Survey, the National Oceanography Centre and nine universities. It is funded by the National Environment Research Council.