Geographically, Ireland is often likened to a saucer: upturned at its mountainous edges and flat in the middle. But that reading doesn’t take account of newly discovered volcanoes south of Mullingar.

The Geological Survey’s Tellus Programme has unearthed aspects of the long buried history of counties Roscommon, Longford and Westmeath.

The maps reveal new detail of 300 million-year-old volcanoes on the Westmeath/Offaly border, which appear in the new airborne geophysical data as a cluster of small magnetic bodies.

The survey, conducted using low flying aircraft, also shows prominent bands of highly magnetic volcanic rocks several kilometres deep near Strokestown, Co Roscommon, which are associated with a major geological fault that can be traced through Ireland to Scotland.

The researchers say these structures are considered important in the development of mineral deposits and their location will be of considerable interest to exploration companies.

The survey aircraft, use technology that effectively sees through Ireland’s often deep glacial deposits and extensive peat cover.

“Tellus continues to reveal extraordinary new detail in Ireland’s geological landscape buried beneath our feet, building upon existing data gaps and developing natural resource opportunities,” said Geological Survey of Ireland principal geologist Ray Scanlon.

The fourth phase of Tellus is underway across the east of the country where the airborne survey over counties Offaly, Kildare, Meath, rural county Dublin and northern parts of Wicklow and Laois is almost 60 per cent complete.

Attention is currently focused on county Dublin.

The aim of the programme is to complete the geological ‘jigsaw’ of Ireland which will support better environmental decision making, radon mapping, smart agriculture and increased investment in mineral exploration.