Research into Ireland's geography prior to the Ice Age could reveal new energy sources, writes Dick Ahlstrom.
Ireland in the past had not one, but at least three massive Shannon-sized rivers that graced its central plain, and the evidence is clear to see for those that know where to look. These same ancient river channels could now provide pure water and geothermal springs.
This history lies under 70 metres of loose overbear, gravel, sand, rocks and clay, the detritus left behind by receding glaciers. The geological record below this material shows that this island was convulsed by geological activity over the millenniums.
Prof Adrian Phillips of Trinity College's Geology Department described some of the efforts to understand our geological past. While the glaciers left our shores tens of thousands of years ago, the activity that formed the island we now see dates back millions of years.
Phillips decided to try to confirm findings made by Trinity colleague, Prof Philip Allen who found that tremendous earth movements over the last 65 million years created the large-scale features of our landscape.
Allen examined the mineral apatite in Irish rocks which provides a kind of "altimeter system" for recording how deep the crystals lay below the surface at different times in the past. He found evidence that Ireland lay below sea level 66 million years ago and was covered by a layer of chalk.
Since then, between one and two kilometres of rock have been scoured from the surface and the whole island was hoisted up hundreds of metres by rising basalt. Another surprising finding was that much of the north Irish Sea was a mountain range up to about 24 million years ago. Three kilometres of rock was removed from these mountains and the debris was dumped off our west coast. Much of the range crumbled when the basalt plume collapsed allowing the sea to return.
Prof Phillips's studies allowed him to prove the presence of massive channels under the midlands overbear, watercourses cut by rivers as big as the modern Shannon. They measure up to three kilometres wide and 140 kilometres long. "If you can imagine canyons or deep valleys that are completely filled up with sand, gravel and clay. You don't see anything on the surface," Phillips says.
These findings have real import for today, Phillips believes. "The channels have considerable potential for clean water reserves, at a time when so much surface water is getting polluted." It may lie no more than 70 metres beneath our feet.
"We hope we can get some geothermal energy out of these channels." Warm springs have been known to exist for years between Dublin and Mullingar. "One of the big channels seems to be running through that zone." He believes temperatures could reach 30 degrees C. The hottest spring known here is near Kilcock, which has a temperature of 23 degrees C after dilution by surface waters. The collapsed structures detected today as sand deposits off our east, west and southern coasts could contain hydrocarbon reserves, oil or gas. At very least it gives the exploration companies a target.