South of Mullingar there lies a 330m-year-old volcano

23 Sep 2015

Residents of Mullingar may have been fearing for their safety after it was revealed a 330m-year-old volcano was discovered on the Westmeath-Offaly border, but thankfully it has been extinct for some time.

The rather surprising volcano discovery was made by the Geological Survey of Ireland as part of its Tellus programme, which uses small aircraft flying at a height of 90m above the ground to take measurements of the Earth’s magnetic field, gamma-ray spectrometry and electrical conductivity.

Onboard the aircraft were three geophysical instruments capable of measuring magnetism, conductivity and natural radiation of the rocks and soils below.

The Tellus aircraft is capable of looking beneath the surface of Ireland and measuring the remaining glacial activity and peat deposits.

And it came as quite a surprise to the Geological Survey team that just south of Mullingar was a cluster of small magnetic bodies which identified it as the site of an ancient volcano.

Named after the Roman goddess of the Earth, Tellus also revealed that there were highly magnetic bands of volcanic rock nearly 7km beneath the town of Strokestown in Co Roscommon.

Tellus plane

The plane used for the Tellus survey

Vital for Ireland’s environment and economy

Linked to a major geological fault which connects Ireland and Scotland, the Geological Society said this is vital information for mineral exploration companies looking to find undiscovered deposits.

Currently, Tellus has its measurement equipment honed in on rural Dublin but has also managed to survey 60pc of Offaly, Kildare, Meath, north Wicklow and Laois.

Speaking of the programme and these recent findings, principal geologist with the Geological Survey of Ireland, Ray Scanlon, said this is all part of vital research for the country.

“The coupling of airborne geophysics and ground-based geochemistry provides a richness of data which places Ireland on a level with other global leaders for the quality, breadth and availability of geoscience information,” Scanlon said.

“An understanding of Ireland’s geology is vital for environmental, health and economic reasons, and the data will be welcomed by a broad range of stakeholders for agricultural, radon prevention, groundwater protection and mineral exploration purposes.”

The magnetic anomoly shown beneath Mullingar using Tellus.

The magnetic anomoly shown beneath Mullingar using Tellus.

Not the Mullingar volcano image via Shutterstock

Colm Gorey was a senior journalist with Silicon Republic