One of the major assets of our Geopark is its geodiversity (see more info here). This diversity of bedrock that attracts regular geological fieldtrips from universities tells the story of the opening and closing of the ancient Iapetus Ocean. And in the Coillte run Tourmakeady woods, you can now get a sense of this geodiversity in a simple 900m walk among the trees, by the river Glensaul and towards the glorious waterfall.

Notre Géoparc can boast to include bedrocks from all types spanning a geological story of 700 million years. The history of the opening and closing of the Iapetus Ocean is illustrated in the Dalradian Supergroup with its range of metasedimentary rocks (quartzites, schists, marbles) describing the earlier deposition during the opening phase in the Neoproterozoic and their later metamorphism during the closing phase in the Ordovician. The arc volcanism of the early Ordovician associated with the closing phase is represented by the Lough Nafooey group of pillow basalt and the Tourmakeady succession that includes rhyolite. The South Mayo basin contains a range of sedimentary rocks from the Ordovician and Silurian from conglomerates to sandstones. Carboniferous limestone is also extensively present to the east of the Western Lakes and a number of magmatic intrusions are also present that include the extensive Galway granite batholith. These lithologies are clearly distinct and very useful to illustrate the variety of rocks on the planet and of the processes that form them.

Each boulders, of about 1m³, were sourced from local quarries or donated by local landowners and placed in reverse chronology, going back in time as you walk towards the waterfall. And they each have a simple panel describing the specific features of the rock and how they formed. The walk was designed in partnership with Coillte and the local community of Tourmakeady and with expert help from Dr Brian McConnell and Dr Nancy Riggs.