New Bedrock Geology map of Ireland
Geology Matters 16

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New Bedrock Geology map of Ireland
Brian McConnell, Land Mapping Unit, GSI

The GSI ‘Geology of Ireland’ map (“Schools Map”), which is aimed at secondary school level and accompanies our book on Irish geology, is nearly out of print, so we have taken the opportunity to replace it with a proper 1:1M scale digital data set, as a contribution to international and derived products.

The starting point was the island of Ireland 1:500,000 map, published in 2006 as a collaborative product with the Geological Survey of Northern Ireland.

To derive the 1M map, 83 units were grouped into 35 units of related rocks and the outlines smoothed to the new scale.

The 1M map was initially served up online for the international New 1:1 million Bedrock Geology of Ireland map  OneGeology map project (, coded by IUGS chronostratigraphical age or international lithological classification. A proper island of Ireland map, however, should present the specific geological history and combine age and lithology in a lithostratigraphical scheme. For example, preserving the Dalradian distinct from other Neoproterozoic metasedimentary rocks, or distinguishing the Silurian sandstones of Iapetus-margin Longford-Down from those of post- Grampian basins in Mayo.

For the printed product, we have used the Emodnet project map ( compiled by the Marine section in GSI, plus some British Geological Survey mapping, to continue the geology offshore and fill the white space traditionally seen in the areas covered by sea.

Launch of new schools Geology map
Former Minister Fergus O’Dowd at launch of new Schools Geology Map, with local students,
Molly Brown (to left) and Clara Cowan (to right) both are Year 9 students at Sacred Heart
Grammar School Newry. The map was launched at the GEOExpo in Newry, organised
by Mourne Cooley Gullion Geotourism Expo in Newry.

The map has separate onshore and offshore legends but a fairly seamless visual appearance.

The aim is that it is sufficiently attractive and easy to read to be useful in education, while at the same time being sufficiently detailed for use as a technical overview of the bedrock geology of Ireland and a contribution to international projects and derived map products.

New Geology map
A pdf download is available on The printed version of the map, with Irish language on one side and English language on opposite side, will be available before schools reopen in September.