Tuesday, February 19, 2013

Formation Of Ireland As We Know It



Irelands physical geography is very unique and shows clearly how the island as we know it today was formed.  Often compared to a saucer or frying pan because of the low lying center raised edges, costal mountains surround the lower middle plain of the island making for beautiful scenery and interesting geographic inquiry.   Ireland is the product of several natural processes that help explain the landscape.
The coast is lined with small mountains that encircle the lower lying central plain
      Plate tectonics are responsible for the bulk of the physical features that define the island.  Ireland, as it is today, is on the Eurasian Plate, but the distinguishable north western part of Ireland was once part of the tectonic plate that now makes up the North American Plate.  These two plates collided 400 million years ago when a divergent plate boundary stopped spreading and the two plates were forced together. The resulting convergence, combined with the duration of that convergence, caused compression that led to major mountain building and syncline folding that can still be observed today. 
Copyright of the Geological Survey of Ireland 2006.

An example of some syncline folding left behind by the convergent boundary that  helped
create the mountainous coast of Ireland


The latest mountain building event to leave its mark on Ireland could be thought of a reversal a of the prior plate convergence.  Shifts in the lithosphere caused a divergent plate boundary to re-form along the.  This produced lava flows and sea floor spreading that ultimately created the Atlantic Ocean by forcing the Eurasian and North American Plates appart.  This volcanic activity in the area also left its mark on the island,  Slieve Gullion mountain is the remnant of a volcano that is encircled by great examples of ring dykes.  There are many conflicting theories about what type of volcano it was since it has a complex rock makeup and has been eroded by glaciers that covered the island at least twice.




Ireland's landscapes not only makes for nice pictures, but in understand how they were formed a broader picture can be drawn about the island, as well as the world have been shaped by a slow but tumultuous  past.


Sources:
http://www.doeni.gov.uk/niea/index.htm
http://www.ringofgullion.org/
http://www.ireland-information.com/