Northern Ireland

Unlocking the secret of Ireland's past

Image caption Has Ireland always been cut off by sea?

Could you have walked from Italy to the west coast of Ireland without getting your feet wet thousands of years ago?

Or has Ireland always been cut off by the sea?

It is an age-old question and many dubious theories have sprung up over the years. The alleged fact that St Patrick chased the snakes out of Ireland is just part of the many myths and claims.

The way the sea levels behaved around the north and south of Ireland had considerable bearing on the last ice age.

If scientists can unlock the secret, their colleagues around the world will be a lot wiser about the way past ice ages have influenced our present environment, as well as the possibility of a land bridge.

It also allows us to better understand how climate change may influence the environment in the future.

"The question as to whether Ireland and Britain were ever connected by land has never been answered satisfactorily," said Professor Andrew Cooper of the School of Environmental Science at the University of Ulster.

"There are many competing hypotheses based on everything from the different mammal populations, archaeology, and computer modelling. Nobody has ever looked at the geological evidence that is preserved on the sea floor. "

A group of researchers are about to begin a three year project to chart parts of the seabed in great detail looking for submerged shorelines, river valleys and deltas throughout the Irish Sea.

"We will carefully analyse all this information to find sites where we can extract material from these submerged shorelines that will allow us to radio carbon date them," he said.

"Next year we will go back on a bigger ship and collect cores of sediment from those locations to help us reconstruct the past environment."

Image caption What is the truth about the Giant's Causeway?

If the core samples provide organic material like peat or leaves then it is possible to accurately date the period when that land was about sea level and even how long it remained so.

Professor Cooper described the finding of such material as the "Holy Grail" of the research project.

While this is a research survey providing very local information, it is described by the Natural Environment Research Council (NERC) as being of "outstanding exceptional scientific merit", the highest possible research ranking possible.

"As well as recording global changes in the volume of the ocean, the sea level record is a yardstick for unravelling how ice interacts with the earths crust," said Professor Cooper.

"The northern part of the British Isles was covered with thicker ice during the ice age, and this was the last to melt.

"We know that land is pushed downwards under the weight of the ice and then bounces back when the ice is removed. Because of this, sea level in the British Isles records the combined effect of global changes in the ocean and regional changes from climate change.

"The British Isles sea level record is of global importance when it comes to understanding how the earth responds to ice loading and unloading".

The research team includes specialists from the north and south of Ireland, from universities in England, the USA and Canada.