The Connemara coastline
The coastline of Cleggan head is fascinating. After discovering it ourselves by kayak a few years back we were amazed, and it wasn’t long after that we decided to start our cave tours around this spectacular location!
We find the beauty of the area draws people from all over the globe, and so what makes it so unique in Connemara?
Well, the rock that forms the cliffs is quartzite and is characteristic of the district, it is the hard, white basis that forms the Twelve Bens. There is softer rock here such as sandstone and other glacial deposits like till. All along this stretch of coastline you can find examples of glacial activity.
These types of rock coupled with the wild Atlantic beating against for hundreds of years and the steep cliffs is how bays and headlands were formed…and eventually caves, arches and stacks
A bay is an inlet of the sea where the land curves inwards, usually with a beach. Hard rock such as quartzite is more resistant to the processes of erosion. When the softer rock is eroded inwards, the hard rock sticks out into the sea, forming a headland.
Caves, arches, stacks and stumps are erosional features that are commonly found on a headland.
The process
1. Cracks are widened in the headland through the erosional processes of hydraulic action and abrasion.
2. As the waves continue to grind away at the crack, it begins to open up to form a cave.
3. The cave becomes larger and eventually breaks through the headland to form an arch.
4. The base of the arch continually becomes wider through further erosion, until its roof becomes too heavy and collapses into the sea. This leaves a stack (an isolated column of rock).
5. The stack is undercut at the base until it collapses to form a stump.