The Variscan Orogeny From about 320 to 290 million years ago, more continents were bashing into each other. Geologists refer to this event as the Variscan Orogeny. As a result of the Variscan Orogeny, another mountain chain sprang up to the south which altered the rocks of Cork. When continents collide, a lot of dramatic things happen: ocean floors and deep rocks are pushed up onto land, rocks layers are compressed and heated and, more relevant to Cork, solid rock starts moving, bending, folding and breaking dramatically.
The folding of the rock layers of Cork City due to the Variscan Orogeny took millions of years, but was an immensely powerful event nonetheless.
This folding took place over many millions of years and would have caused many earthquakes. We see this today as the huge folds and faults in the rocks of Cork, and it gives the rocks in Cork City their characteristic appearance. These appear on different scales: across the entire county, the folds on the scale of kilometres make rock layers dip up and down across the landscape like waves. On a smaller scale in Cork City, we see geological folds on the scale of several metres. Finally on a human-sized scale, we see smaller folds and also linear/planar textures in the rock known as cleavage. These textures can be compared to the look of elongated grains in wood. The directions that the cleavage textures tell geologists in from which direction the rocks were deformed. Eventually, the continents stopped colliding and Cork was now part of an even bigger continent. Actually, this was a supercontinent called Pangea and it was made up of nearly every other current continent.
13
Powered by FlippingBook