Mayo location included in prestigious world geological heritage sites listing
In the second major geology-related accolade in 2026 in Mayo-Galway, an area from Clew Bay to Galway Bay has been included in a top selection of world geological heritage sites as having significant value for education and learning.
Known to geologists as the Grampian-Taconic Orogeny transect in Connemara and South Mayo, this site covers about 4000km2 between the two bays, and to the west of Lough Mask and Lough Corrib.
The recognition is due to its very rich Geodiversity (range of different types of rock) including the most complete and accessible record of the opening and closing of the Iapetus Ocean (ancient ocean that separated Ireland in two halves until 400 million years ago).
The rocks also record the formation of ancient mountain ranges, now worn down, that were formed by the tectonic processes linked with the closure of this ocean.
A large part of the area is included in the Joyce Country and Western Lakes area, which achieved UNESCO Global Geopark status in April 2026.
World-famous Connemara Marble is the most commonly recognisable rock in the region. Others include granite, volcanic rocks and quartzite – one of the hardest rocks found in nature and forming the peaked mountains in the region of the 12 Bens and Maumturks.
This region has been studied by geologists for over 200 years, rising to global recognition through the application of plate tectonics to ancient mountain building (orogens) in the 1960s.
Today the site and the associated UNESCO Global Geopark are ideal locations for outdoor education and state of the art research.
“This IUGS listing of the wider region highlights the work of generations of geologists and recognises it as one of the best sites in the world to explore, study and research geology.” noted the Geopark geologist Dr Benjamin Thébaudeau, attending the IUGS conference in Portugal.
“It really puts us on the map, and will attract more education groups of all ages to study and learn.”
The selection of the Third 100 builds on the success and global impact of the First 100, announced in 2022, and the Second 100, announced in 2024.