Global cooling in Europe began in the Tertiary Period culminating in the Ice Age about 1.7mya. During the Ice Age the climate alternated between cold and warm stages and Ireland's last cold stage only ended 10,000 years ago. The Iveragh Penninsula shows every kind of mountain glaciation from the past such as can be found in the Alps, Scandinavian and Alaskan Mountains. 7000 BC Ireland was joined to the Iberian Penninsula, Denmark but not to England.
One of the later events during the Cork/Kerry glaciation was the formation of a great ice centre in the upper part of Kenmare Bay, around the Templenoe area. The major glacier moved westward and was joined by several glaciers which broke through the mountains from the north and by smaller corrie glaciers. The entire ice mass moved along the southern edge of the Geopark area. Evidence of its movement can be found in the smoothing of the rocks and the scraping of their surface (striae) at Lough Fadda and Coongar Harbour near Tahilla.
1m years ago Kenmare Bay was a mass of ice. A sheet of ice drove north from Bantry and left debris on its way eg. east of Lough Currane. Rocks were rounded as in the Long Lake and Molls Gap. The ice withdrew into the cooms- Coom Caillee, Coom Casig, Coumnahorna- and scooped out lakes like the Upper Lake, Coom Caillee Lake and other lakes in Sneem- Caherdaniel. The mountains around Sneem are full of scooped glacial hollows called cooms from the Irish word for "bent".
The last of the ice caps was formed in Kenmare estuary; the high grounds exercise control but in places a tongue of ice gouged out a valley eg Gap of Dunloe. Its final retreat was into the Black Valley.
Glacial Breaches The ice which pushed through the mountains from the north, breaking through from one valley to another formed glacial breaches. The Glenmore Breach and Staigue Breach are evidence of this type of movement. Corrie Lakes
The evidence for the many small mountain glaciers is found in the presence of small deep lakes high up in the mountains. During the cold periods snow fell on the sheltered lee of the hills and turned to ice. Eventually the accumulating ice could no longer hang on to the hillside and began to flow down into the old river valleys. The continuous movement of ice in and out of the hollows, along with the pebbles and rocks which it carried, gradually gouged out and deepened the depressions leaving a corrie or cum filled with water when it melted. This type of feature is very common within the Geopark area.
As the ice moved down the river valleys as valley glaciers, loaded with rock debris, it straightened out the valleys and deepened them. The landscape to the north-east of Sneem contains classic examples of corries and valley glaciation.
Some Corrie Lakes in the Kerry Geopark -Coomrooanig
Lough Sallagh (Esknaloughoge)
Lough Sallagh (Finnararagh)
As the corries were sculpted out and the valleys were deepened the resulting rock was carried forward by the glacier. When the ice melted it was dumped. Evidence of this is found in the cross-sections of the coastal cliff between Hogs Head and Waterville which consist of moraine or glacial till. This dumped material was also responsible for blocking existing water flow channels and creating lakes. Lough Currane is the largest of such moraine locked lakes on the Iveragh Peninsula. Glacial till deposits can also be seen a little east of the Derrynane Hotel on the N70 Kenmare Bay is also a product of the ice. It is a broad-mouthed drowned valley or ria formed in a major synclinal valley. The valley was formed by earth movements in the late Tertiary Period but it only became submerged to approximately its present depth before the growth of the Quaternary Period ice sheets.