Complete History of Ireland

Around 600 million years ago, what today is Ireland lay in two halves down near where North Africa now is. At this time Ireland lay beneath a tropical sea, which allowed layers of sand and mud to build up on the sea floor, forming sandstone and mudstone. As the North American and European continental plates collided, Ireland's two halves united and buckled to form several fold mountains, e.g. the Wicklow Mountains. The sedimentary rocks that had been resting on the sea floor were put under great heat and pressure, turning them into metamorphic rocks. The mudstone turned to slate and schist, while the sandstone became quartzite. The lava which came to the surface during this collision cooled and turned to granite, an igneous rock. Granite, slate, schist, and quartzite are today the most common rocks to be found around the fold mountains created in this collision. Elsewhere in Ireland, other sedimentary rocks (most notably Limestone, formed when layers of decaying sea creatures built up and compressed) and Igneous rocks can be found.

At this stage (around 400 million years ago) Ireland was above sea level, near the equator. Plants and land-animals lived on the land in this period. Most of Europe then sank underwater again. Many tropical reefs grew, forming limestone in the centre of the country. As the water level fell again, swamps and forests flourished, with their remains forming coal. This coal and much limestone was eroded as Ireland rose further out of the water and was carried North by continental drift.

The next time Ireland was submerged (about 200 million years ago) it was no longer in an area that could support tropical reefs. This sea left behind large chalky deposits on Ireland's landscape. Around 65 million years ago Ireland became a volcanic land, with many volcanic mountains, such as the Mourne mountains, forming.

From 25 million years ago to present, Ireland began assuming it's current position and climate, with erosion creating our current landscape.

This picture roughly shows the journey that Ireland has taken over the last half a billion years. A and B united at the multicoloured dot before drifting upwards.


















Picture from http://geography.about.com/