FOR YEARS scientists have speculated about whether a land bridge ever existed between Ireland and Britain. An international sea bed study now hopes to provide a definitive answer to this question.
Prof Andrew Cooper of the University of Ulster and seven other researchers set sail tomorrow morning from Castletownbere, Co Cork. He will lead the research, which also involves scientists from Trinity College Dublin, the British and Irish geological surveys and others from universities in Britain, US and Canada.
Although funded with more than €1 million from the UK’s Natural Environment Research Council, the project has attracted significant international interest.
This is because the study will also show how land pressed down by glaciers during the last ice age springs back when the ice melted, Prof Cooper said.
Sea level was much lower 15,000 years ago when massive glaciers blanketed the earth. Water trapped as ice meant sea level was 60 metres lower off our southern coast than it is today.
The south probably remained ice free but northern Britain and Ireland were pressed down by billions of tonnes of ice. Here sea level was perhaps 30 metres lower, but the northern part of the island even today continued to rebound upwards, he said.
The researchers will spend the next three years looking for physical evidence of where these ancient coastlines were located.
First they will map sea floor structures, pinpointing submerged deltas and river valleys and also former coastlines marked by signs of erosion. Next year they will go back and collect cores of sea bed sediment from locations of interest.
“If we get peat we can look at the pollen in it to help us reconstruct the past environment,” Prof Cooper said. It will tell them about the types of plants growing then and the environment. They can also carbon date the samples.
They will look at sites off Bantry Bay, Waterford, Cardigan Bay in Wales, Drogheda, Britain’s Morecambe Bay due east from the Isle of Man and Belfast Lough.
Prof Cooper has decided not to prejudge what they will find, but has a view. “The highest likelihood is if there was [a land bridge], it had to have been in the south. I still think it is a bit of a long shot.”
The study will help build better computer models for what happens when the land lifts upwards as ice melts. It could be used to understand the changes to come as Greenland’s glaciers melt.
