To watch an animation on fold mountain formation, go to YouTube and search for ‘Mountain building animation – Tectonics Observatory’ (0:16).
2. Anticlines and synclines
4.2 Distribution and Periods of Fold Mountain
Formation There have been three major periods of fold mountain formation: the Caledonian period, the Armorican period and the Alpine period.
1. Caledonian folding occurred 400 million years ago. In Ireland, the Dublin–Wicklow Mountains were formed during this period. Mountains formed during this period of folding have been worn down over time.
2. Armorican folding occurred 250 million years ago. Many Munster fold mountains were formed during this time, for example, MacGillycuddy’s Reeks in Kerry and the Galtee Mountains in Tipperary. These mountain ranges were once as high as the Alps but have been worn down over time.
3. Alpine folding started 35 million years ago and is still taking place today. These are the youngest and highest fold mountains in the world. They are so high because they have not yet been worn down by weathering. They include the Rockies in North America, the Himalayas in Asia and the Alps in Europe.
Managing information and thinking
Using an atlas or Google Maps, locate and identify the mountain ranges labelled 1–5 in figure 3.
1 4 3. Distribution of fold mountains in Munster 3 5 2
What evidence in this photo tells us that this rock has been folded?