A World of Ice and Fire: the geology of the Game of Thrones...by Kirstin Lemon

Northern Ireland :
The Real Westeros

For its size, Northern Ireland has some of the most diverse geology in the world.  This incredible geology has led to the development of a vast array of natural landscapes many of which, like the Giant's Causeway, are famous throughout the world.

This stunning geology hasn't gone unnoticed by the TV and film industry and many locations across Northern Ireland have been the settings for some high profile filming. 'Dracula Untold', released in October 2014, was filmed at numerous locations including at the Giant's Causeway's famous basalt columns, and at Scrabo Country Park, known for its beautiful pink sandstone used in many local buildings. The recent BBC drama 'The Fall' whilst based in Belfast, used the surrounding Belfast Hills as the backdrop for many of its more sinister scenes easily recognised by the characteristic layers of white limestone, overlain by black basalt.

                     Carrickarede viewed from the mainland                    

But perhaps Northern Ireland is most notable for being the location for filming a huge portion of HBO's multi award-winning fantasy drama series 'Game of Thrones'. The series is set on the fictional continents of Westeros and Essos, with Northern Ireland being the filming location for most of Westeros. Discover Northern Ireland have produced a tourist map guiding visitors to the main filming locations. We've provided a taster of some of the geological Game of Thrones locations and fans won't have to travel very far to come across somewhere that looks just more than a little familiar.

Starting in the north-west, the stunning beach of Downhill is the location for Dragonstone chosen because of its dramatic basalt cliffs that tower over the beach below. Formed from a series of lava flows around 60 million years ago, the basalt cliffs are notoriously unstable at this location causing a serious engineering headache due to the presence of a train line at the base of the cliff.

Following the famous Causeway Coastal route to the east, the next filming location is Larrybane, or The Stormlands to Game of Thrones fans. Larrybane translates from the Irish as 'white headland' and this classic outcrop is formed from Cretaceous white limestone, formed around 80 million years ago, and more commonly known as chalk. Just along from Larrybane is Carrickarede, an explosive volcanic vent that would have burst its way through the limestone at the beginning of the Palaeogene period around 60 million years ago and well known for its nail-biting rope bridge.

Slemish Mountain

The next stop on the journey is the beautiful harbour of Ballintoy, used by hundreds of geology students every year for its accessible outcrops of limestone and basalt. This tranquil harbour was built to transport amongst other things, quicklime, a form of processed limestone that was produced in the purpose-built lime kilns at the harbour. Ballintoy was transformed into Pyke, in the Iron Islands for Game of Thrones and is perhaps one of the most easily recognisable locations.
As you continue along the Causeway Coastal route, the village of Cushendun is next on the list of film locations. Again, a spot for many geology students every year, if nothing else for a break from the limestone and basalt that dominates this area. The caves at Cushendun are conglomerate, a rock made up of numerous large pebbles that were carried here from a desert upland area by flash floods over 400 million years ago. The caves are where Melisandre (or the Red Witch) gave birth to the shadow baby in one of the more fantastical scenes in the series.



            Magheramorne Quarry with King's Landing in the           
            foreground and Castle Black perched on top of the          
            white limestone with black basalt behind           

The next location on the list is not far from the town of Ballymena. Already a religious pilgrimage site in its own right, Slemish Mountain is a Palaeogene volcanic plug composed of dolerite. Due to its different composition from the surrounding basalt, it has eroded at a different rate and can be seen standing proud on the landscape for miles around. There are a number of such plugs on the Antrim Plateau, all associated with a period of volcanic activity around 60 million years ago, but Slemish is by far the largest. The surrounding area was transformed into the Dothraki Grasslands for Game of Thrones.


One of the sites that you won't find on any of the tourist maps is Magheramorne Quarry, just south of Larne. This disused quarry was earmarked for development as an eco-village before the recession but has found a new lease of life as the set for King's Landing and Castle Black in Game of Thrones. The quarry was worked for white limestone, and it has the typical overlying basalt geology. In between the two is the clay-with-flints deposit, originally thought of as being a residual weathering product, and later as a volcaniclastic deposit. Both of these theories are being revisited so check back for further updates. Because of the importance of the clay-with-flints, this site is being designated as an Area of Special Scientific Interest (ASSI) which allowed for BGS scientists to gain access to the quarry.  

Landscapes surrounding Castle Ward

Moving much further south and this time to the shore of Strangford Lough, the grounds of Castle Ward were used for filming Winterfell (Old Castle Ward itself) and Rob Stark's Camp. The more subdued landscapes of the area surrounding Strangford Lough were shaped by ice during the last glaciation and are home to one of the most impressive drumlin fields in the country.

The last stop, and the most westerly point for filming is Pollnagollum Cave located in the Marble Arch Caves Global Geopark. The cave can be found in Belmore Forest and was used as a Victorian show caves long before the Marble Arch Caves were even dreamt of. Access to the cave is down through a collapsed cave roof, and like the majority of the bedrock in this part of Co. Fermanagh they are formed out of Carboniferous limestone that was deposited around 340 million years ago.

Pollnagollum Cave

Due to the growing number of visitors wanted to visit the filming locations, in addition to the tourist map of the main locations for filming, there are numerous tour companies taking visitors to key locations. So if you love Game of Thrones and love geology then perhaps now is the time to come and see one of the largest natural film sets in the world!

For further information on any of the geological sites mentioned then contact Dr Kirstin Lemon at klem@bgs.ac.uk