60 million years ago wasn’t the only time this part of Ireland experienced igneous activity. The rocks that make up Camlough Mountain is called granodiorite. Granodiorite, just like the rocks that make up Slieve Gullion, forms from the cooling, deep underground, of molten magma. However unlike the rocks that make up Slieve Gullion and the Ring of Gullion, the granodiorites of Camlough Mountain are around 410 million years old. Whereas the younger rocks of Gullion are associated with igneous activity related to the formation of the present day Atlantic Ocean, the rocks of Camlough Mountain are associated with igneous activity related to the closure of a precursor to the present day Atlantic, the now long disappeared Iapetus Ocean. This lost ocean disappeared as ancient continents moved together and eventually came into collision between 470 and 400 million years ago. In the final stages of this long, complicated process, large volumes of magma were generated deep in the Earth’s crust. They later cooled to form the granodiorirte we see today. These continental collisions not only created a range of mountains of Himalayan proportions (the eroded remains of which form today’s Sperrin and Donegal Mountains) but it also stitched together the two parts of Ireland (the north and west as well as the south and east) which had been stranded on parts of different continents on opposite sides of the Iapetus Ocean.
Posted on 14th August 2021
Linen & Lace Exhibition- A Rich Heritage