Cliffs Of Moher

Cliffs of Moher – Geosite

The Cliffs of Moher and Visitor Centre are open all year round. Highlights include over 800m of cliff edge paths and viewing areas, the gothic style 19th century O’Briens Tower near the highest point of the cliffs and the eco-friendly underground visitor centre building containing visitor services and facilities, gift shop, restaurant & coffee shop and the award winning Atlantic Edge Exhibition.
As a special protected area (SPA) for seabirds the Cliffs are home to over 30,000 pairs of seabirds. Internationally significant numbers of both Guillemots and Razorbill can be found here along with Puffins, Kittiwakes, Fulmars, Peregrine Falcons and Choughs.

Cliffs of Moher – Geology

One of the most visited tourist locations in Ireland is also a Geosite because the 5km of cliffs display a spectacular example of an ancient infilling marine sedimentary basin.

Deltaic sediments

Some 320 million years ago a continent existed to the southwest of the present-day Cliffs of Moher. Massive rivers drained mountain ranges and carried enormous quantities of mud and sand. As these rivers eventually reached the sea they started to deposit the sediment. The amount of sediment was so large that a large Delta, similar to the Mississippi River Delta of today, began to form.

The rock layers near the base of the cliffs are the oldest and were deposited in fairly deep water, as more sediment was supplied the deposits began to accumulate and build out into the sea and those deep water layers were covered by progressively shallower water deposits until at the top of the Cliffs of Moher there is evidence that the area which was once marine had become land.

This change is recorded in the fossils found in the Cliffs which change from marine, free-swimming goniatites to terrestrial land plants.

Trace Fossils

As you walk around the Cliffs of Moher Visitor Centre you will notice that the walls and footpath are lined with slabs of rock with curious and distinctive sinuous markings. These flagstones (known locally as ‘Moher Flags’) are quarried from the top of the Cliffs of Moher and the sinuous markings are the traces formed by unknown creatures that burrowed through the sand and mud nearly 320 million years ago. These flagstones are used for building stone and have been exported overseas since the 1800’s.

Birds

As well as their considerable geological importance the Cliffs of Moher are also home to the largest colony of nesting seabirds on mainland Ireland. The area has been designated a Special Area of Conservation and is protected under the EU habitats Directive. Some of the birds include; Puffins, choughs, kittiwakes, guillemot, razorbills and fulmar. In the sea below, whales, basking sharks, dolphins, seals and otters are found.