Marble Arch Caves
The Marble Arch Caves are a series of natural limestone caves located near the village of Florencecourt in County Fermanagh, Northern Ireland. The caves are named after the nearby Marble Arch, a natural limestone arch at the upstream end of Cladagh Glen under which the Cladagh River flows.
The caves are formed from three rivers draining off the northern slopes of Cuilcagh mountain, which combine underground to form the Cladagh. On the surface, the river emerges from the largest karst resurgence in Ireland, and one of the largest in the United Kingdom.
At, the Marble Arch Caves form the longest known cave system in Northern Ireland, and the karst is considered to be among the finest in the British Isles.
History
1907–1908: Great Boulder Chamber and dye tracing
In 1907, English cavers from the Yorkshire Ramblers' Club began exploration in the area, and without access to a boat they decided to wade the section of underground river as far as The Junction, subsequently reaching the extent of Martel and Jameson's explorations. Bolstered by the experience, and the good possibility of further discoveries, the Yorkshire Ramblers returned in Easter 1908. A group of cavers descended a pothole located close to the large dolines on the plateau and discovered the Great Boulder Chamber. After a few hours of exploring, they realised that they had found a new route into Pool Chamber, bypassing the deep water of the original entrance.During the 1908 explorations, the Yorkshire Ramblers conducted tests to ascertain the hydrological connections between caves. They performed a dye tracing experiment with fluorescein, establishing a direct hydrological connection from the Aghinrawn River sink at Monastir cliff, via Upper Cradle Hole Cave, to the Cladagh Glen resurgence. While surveying Lower Cradle Hole Cave, one caver sent a floating candle downstream along the river, until it floated under a low ceiling out of sight at the end of the known passage. On plotting the surveyed passage on a map alongside Marble Arch Cave, it was apparent that only separated the end of this passage from the upstream end of the Grand Gallery, and it was postulated that a connection between the two might be forged.
1935–1938: Skreen Hill and connections
No further exploration was made until Easter 1935 when another group from the Yorkshire Ramblers' Club made their way from England. In wet conditions, the cavers re-entered Pool Chamber via the entrance found in 1908, and after some investigation discovered a high-level crawling passage exiting the chamber. The passage ended high in the wall of New Chamber, a cavern of considerable size, where the upstream continuation of the river was found. Exploration was halted here as the water was too deep to pass.The club returned to New Chamber in 1936 to explore and survey the ongoing Skreen Hill passage, named after the hill on the surface above. After of walking passage, the cavers stopped at a deep lake. This section of deep water is where the path of the current show cave ends. When club members returned again in 1938, they brought an inflatable dinghy, allowing them to progress across the lake, only to discover that the way on was blocked by Sump 1, just from the shore.
During the 1935 expedition, another group of cavers explored Lower Cradle Hole Cave. On reaching the downstream end of the cave, they discovered that water levels were now low enough to see a series of low arches above the water surface. By anchoring a floating candle part-way through the passage, exiting the cave and returning to the end of the Grand Gallery in Marble Arch Cave, the cavers confirmed that the passages were connected; subsequently, two of the party swam through to make the first through-trip between Marble Arch Cave and Lower Cradle Hole Cave.
1966–1967: Skreen Hill 2, 3 and Legnabrocky Way
By the mid-1960s, a number of advancements had been made in cave diving, by which method speleologists had extended their explorations into caves beyond the sumps that would normally have halted progress. In December 1966 divers Dave Cobley and Mike Boon made preparations to dive Sump 1 in Skreen Hill passage. Before making the dive however, they investigated a small dry passage leading off on the left bank of the lake, finding it to be blocked at the end by unstable boulders in the roof. The cavers removed one of the boulders to reveal a way on, which led via a dry route to the far side of Sump 1. The new section of river passage beyond was named Skreen Hill 2, and a further inlet passage was named Legnabrocky Way. A notable feature of the Legnabrocky Way is the Giant's Hall, a large chamber 60 m long, 30 m high and 15 m wide. Despite only carrying a small stream, the Legnabrocky Way is the largest section of passage in Marble Arch Cave.The upstream continuation of the river in Skreen Hill 2 was found to be shortly blocked by Sump 3, so in March 1967 a team of divers returned to attempt further exploration. William Frakes and John Ogden were the first to successfully pass the sump to reach Skreen Hill 3, of "magnificent stream passage" ending in boulder choke. In the ensuing months a comprehensive survey was made of all of Marble Arch Caves, including the newly discovered sections. During this time, surveyors learned of the deaths of Frakes, Ogden and Colin Vickers—another of the divers in the original team—in the Mossdale Caverns accident. In tribute, a number of cave features in Skreen Hill 3 were named after the three cavers.
1982–1985: show cave development
From 1982, until after opening in 1985, sections of Marble Arch Cave underwent development to improve accessibility in order to accept tourist visitors. As well as concrete pathways, safety barriers and electric lighting, this involved installing weirs and jetties for boat access to enable visitors to enter the caves by the same route that Martel and the early explorers took.The development also included boring a new entrance shaft into Skreen Hill and, significantly, excavating a corridor using quarrymens' plugs and feathers through the short section of rock separating Pool Chamber from New Chamber. This connected Skreen Hill all the way to The Junction for walking visitors for the first time.
At this time, all known entrances to the cave system were gated to control access. From then on, cavers were only allowed access by agreement with show cave management. The show cave has since become established as a popular tourist attraction.
1995: Cradle Hole tragedy
Three cavers died on a trip into Lower Cradle Hole on 15 January 1995. They were in a group of ten cavers, mostly students from University College Dublin and Dublin Institute of Technology caving clubs, when the three were swept away by fast running water and drowned in the low air-space section of passage between the end of Lower Cradle Hole and the Grand Gallery in Marble Arch Cave. Those killed were Philip Marshall, Brian Patrick Kennedy and Conleth Cormican.A memorial plaque outside Lower Cradle commemorates the disaster, and the entrance remains accessible to cavers via a gate. Three oak saplings were also planted on the grassy area south of the car park by each of the families on the tenth anniversary of the accident.
2009–2010: diving connections
In 2009 and 2010, diving connections were made to nearby cave systems by Artur Kozłowski. Kozłowski made the first connecting dive to Prod's Pot – Cascades Rising, doubling the total length of the system from. Subsequently, he and Chris Jewell connected the newly established Monastir Sink – Upper Cradle system, extending the Marble Arch system to. The discoveries make this the longest cave in Northern Ireland.Hydrology and development
The Marble Arch Cave system is chiefly formed from three rivers which drain off the Marlbank area on the north side of Cuilcagh mountain. From west to east, these tributaries are the Sruh Croppa, the Aghinrawn and the Owenbrean.The Prod's Pot – Cascades Rising section of the system has a complex hydrology which includes drainage from at least five small sinks on the eastern Marlbank ; sections of the Owenbrean River upstream of its main sink at Pollasumera; and most notably Goat Pot, Aghatirourke Pot, Pigeon Pots and Badger Pot on East Cuilcagh, nearly to the southeast.
Of these, Goat Pot and Aghatirourke Pot have also been traced to Tullyhona Rising ; Pigeon Pots, Badger Pot and Aghatirourke Pot also flow to Gortalughany Rising ; and Badger Pot and Pigeon Pots also flow to Shannon Pot on the far western slopes of Cuilcagh.
Show cave
Édouard-Alfred Martel first postulated that Marble Arch Cave would make a worthy show cave after initially exploring the system in 1895. However, it was not until 1982 that work eventually began on creating a new underground tourist attraction. Development included:- Building concrete and metal walkways with handrails throughout the show cave;
- Installation of electric lighting;
- A new tunnel between Pool Chamber and New Chamber, providing walking access to Skreen Hill passageways;
- An access shaft and staircase into Skreen Hill passage from one of the large surface dolines on the plateau;
- A short section of walled pathway dug into the floor of the cave, under a low ceiling—the "Moses Walk" is so-called because the river continues to run at shoulder level either side of the path;
- A visitor centre, car park and access road on the surface.
Between 1985 and 2008, the show cave attracted approximately 1 million visitors, from 100 countries worldwide. Annual visitor capacity is 94,060.