Great Pollet Sea Arch is one of Ireland's finest coastal geographical features. Situated off the coast of County Donegal's Fanad Peninsula, the sea arch stands at 20 metres above the crashing waves along this rocky headland.
Known in Irish as Stua Mór Phollaide (Great Pollet Arch), the sea arch as seen here separated from the mainland on the left due to coastal erosion during the millions of years since these rocks were formed.
Here the rocks are quartzite having been formed during the late Precambrian, somewhere between 2.5 billion and 541 million years ago part of the Dalradian Supergroup that runs between the north of Ireland and central Scotland.
As throughout Ireland, much erosion has taken place in the intervening time and at some point, likely in the last 11,700 years which is known as the Holocene (since the end of the last Ice Age) this section of the headland became a bridge with a sea cave eroded through it and then subsequently it became detached from the mainland behind it.
Thus forming what we see today, an impressive sea arch which is Ireland's largest sea arch. Note that a sea stack, such as Dun Briste is different to a sea arch.
