Topic 8: Laurentia, Avalonia, and the Iapetus Ocean

Now that we’ve covered all the main types of rocks, looking at how they form and some of the ways they’ve influenced society, it’s time to think about how all those types of rock come together to form particular places. And what better place to consider than our own island of Ireland. During this week, we will look at how Ireland used to be part of not one but two different continents, called Laurentia and Avalonia, separated by an ocean called Iapetus. We’ll cover what happened to those continents and that ocean, and how those events have had lasting impacts that still influence Irish society today.

Lecture

Lecture slides: L8 Laurentia, Avalonia, and Iapetus

Reading

I suggest reading Chapter 10 of Lutgens and Tarbuck 2015 Essentials of Geology. This is the chapter on the origin and evolution of the ocean floor, and it will help you to understand what was happening during the events described in the lecture.

I would also suggest reading Chapters 2-4 of Understanding Earth Processes Rocks and the Geology of Ireland by Sleeman et al. These cover the Precambrian to Silurian, and will more directly expand on what we cover in the lecture.

Additional

I would also like you to read a short paper on how mining influenced society. The virtual field trip during reading week looked at Parys mine in Wales - at the same time, we had copper mining in Waterford. Cowman, D. 1983 Life and Labour in Three Irish Mining Communities circa 1840. Saothar 9, 10-19

Here’s a YouTube short showing some metamorphic rocks on Mull, in Scotland: The geology of Mull - Ardlanish Beach