Scientists date end of ice age in Scotland
They said analysis of sediment buried beneath some of the country’s deepest and least-explored waters has revealed ice sheets receded 14,000 years ago.
The team, from the £3.7 million Britice-Chrono project, used a range of techniques to examine samples drilled during a 30-day expedition around the north-west Highlands and Shetland.
CT scans, which use X-rays, were the most revealing and helped pinpoint when and how the final British-Irish ice sheet disappeared.
Ice was responsible for moulding the Scottish landscape we see today, through erosion, smoothing and shaping of bedrock and transporting and depositing rock debris.
Dr Tom Bradwell, a lecturer at the University of Stirling, has spent the past two years studying the seabed samples.
He said the high-resolution scans revealed evidence that cannot be seen with the naked eye –micro-fine layers of mud, silt and sand that have settled out of meltwater from the front of an enormous glacier that once filled the Minch.
“This is the first time that we’ve taken continuous high-quality sediment cores from beneath a former ice stream in some of the deepest waters around the British Isles, some of which are still uncharted,” he said.
“Radiocarbon dates from shells found in these cores place the ice sheet margin in the Minch 20,000 years ago. By 16,000 years ago the ice was back on land, and by 14,000 years ago virtually all the ice in Scotland had melted.”
The team believes their findings could provide important insights into modern climate warming, which is causing a rapid melt of polar ice caps.
Dr Bradwell added: “It’s vital that we understand how the last British ice sheet grew and the style and rate at which it receded. At the moment we see massive ice shelves breaking up around west Antarctica, but we don’t know how long this will go on for.
“Working on former ice sheets like the one that covered Scotland allows us to view the whole ice-sheet growth and decay cycle, rather than just get a snapshot in time.
“The similarities between what we see happening in west Antarctica today and what we see on the seabed around Scotland are striking.”
Britice-Chrono is a five-year project funded by the Natural Environment Research Council. Partners include the British Geological Survey (BGS), Scottish Universities Environmental Research Centre and British Antarctic Survey.
Samples were collected using BGS’s hi-tech Vibrocorer, which is set to go on show at the new Unearthed exhibition being held in Edinburgh.
It can take up to an hour to collect each core once the apparatus is on the seabed, according to BGS marine geoscientist Dr Carol Cotterill.
She added: “During the Britice-Chrono expedition the team took a winch with over 1km of cable on it so that they could sample some of the deepest parts of the sea.”