| Marble Arch Caves | |
|---|---|
| Uaimheanna an hÁirse Marmair[1] | |
 "The Castle"gour pool formations in the Marble Arch Caves show cave | |
  | |
| Location | nearFlorencecourt,County Fermanagh |
| Coordinates | 54°15′30.34″N7°48′51.53″W / 54.2584278°N 7.8143139°W /54.2584278; -7.8143139 |
| Depth | 94 m |
| Length | 11.5 km (7.1 mi)[2] |
| Discovery | 1895 |
| Access | Show cave; accessible beyond with permission from Marble Arch Caves centre[3] |
TheMarble Arch Caves are a series of naturallimestonecaves located near the village ofFlorencecourt inCounty Fermanagh,Northern Ireland. The caves are named after the nearby Marble Arch, a naturallimestonearch at the upstream end of Cladagh Glen under which theCladagh River flows.[4]The caves are formed from three rivers draining off the northern slopes ofCuilcagh mountain, which combine underground to form the Cladagh. On the surface, the river emerges from the largestkarstresurgence in Ireland, and one of the largest in theUnited Kingdom.[5]At 11.5 kilometres (7.1 mi), the Marble Arch Caves form the longest known cave system in Northern Ireland,[2] and the karst is considered to be among the finest in theBritish Isles.[6]
The Marble Arch, Cladagh Riverresurgence and three largedolines on theplateau above the end of Cladagh Glen were all known well beforeunderground exploration began; in fact the arch was a popular tourist attraction in the 19th century.[7] As early as the 1730s, the ReverendWilliam Henry described these features, as well as the sinks of the Owenbrean, Aghinrawn and Sruh Croppa rivers which he correctly surmised to be feeders of the system.[8]
Without venturing far into the cave, Henry descended to the base of one of the dolines above the resurgence:
The arch over my head was 20 feet high, continued with a little landing for 100 yards to the other great pit, by the light of which I could observe the river flowing gently along...
— Rev. William Henry, A Natural History of the Parish of Killesher (1732)[8]
The stream passages at the base of eachshakehole were first explored byÉdouard-Alfred Martel andDublin naturalistLyster Jameson in 1895.[9] Using acanvas boat, and with candles andmagnesium flares for light, Martel and Jameson found 300 metres (1,000 ft) of passages,[10] including the junction where the three rivers (the Owenbrean and the combined Aghinrawn and Sruh Croppa) meet.[NB 1][4] They drew amap of the discoveries andline drawings depicting the expedition, noting the upstream conclusion by boat in the Grand Gallery, and on foot at Pool Chamber.[10] Today, this route to Pool Chamber forms part of the walking section of the show cave.[7]
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Martel and Jameson also investigated Cradle Hole, a very large surfaceshakehole 400 metres (1⁄4 mi) south-south-west of Marble Arch. A cave entrance in the north-eastern corner—Lower Cradle—was explored, reaching an underground river and passages with the same proportions as those in the Marble Arch Cave.[10]
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In 1907,Englishcavers from theYorkshire Ramblers' Club began exploration in the area, and without access to a boat they decided to wade the section ofunderground river as far as The Junction, subsequently reaching the extent of Martel and Jameson's explorations.[12] Bolstered by the experience, and the good possibility of further discoveries, the Yorkshire Ramblers returned in Easter 1908. A group of cavers descended apothole 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.[4]
During the 1908 explorations, the Yorkshire Ramblers conducted tests to ascertain thehydrological connections between caves. They performed adye tracing experiment withfluorescein, establishing a direct hydrological connection from the Aghinrawn River sink at Monastir cliff, via Upper Cradle Hole Cave (situated on the south side of Cradle Hole), to the Cladagh Glen resurgence.[4] 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 9 metres (30 ft) 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.[4][13]
No further exploration was made until Easter 1935 when another group from the Yorkshire Ramblers' Club made their way fromEngland.[14] 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.[14]
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 370 metres (1,200 ft) of walking passage, the cavers stopped at a deeplake.[15] This section of deep water is where the path of the current show cave ends.[7] When club members returned again in 1938, they brought aninflatable dinghy, allowing them to progress across the lake, only to discover that the way on was blocked bySump 1, just 40 metres (132 ft) from the shore.[16]
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.[14]
By the mid-1960s, a number of advancements had been made incave diving, by which methodspeleologists 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 unstableboulders 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.[17] The new 200-metre (660 ft) section of river passage beyond was named Skreen Hill 2, and a further800-metre (1⁄2 mi)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 (200×98×49 ft).[7] Despite only carrying a small stream, the Legnabrocky Way is the largest section of passage in Marble Arch Cave.[18]
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 ofdivers returned to attempt further exploration. William Frakes and John Ogden were the first to successfully pass the 25-metre (82 ft) sump to reach Skreen Hill 3, 640 metres (2,100 ft) of "magnificent stream passage" ending in boulder choke.[17][18] In the ensuing months a comprehensivesurvey 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 theMossdale Caverns accident. In tribute, a number of cave features in Skreen Hill 3 were named after the three cavers.[17]
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.[19]
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The development also included boring a new entrance shaft into Skreen Hill and, significantly, excavating a corridor using quarrymens' plugs and feathers (instead of potentially damaging explosives)[citation needed] 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.[citation needed]
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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.[3] The show cave has since become established as a popular tourist attraction.[20]
Three caversdied on a trip into Lower Cradle Hole on 15 January 1995. They were in a group of ten cavers, mostly students fromUniversity College Dublin andDublin Institute of Technology caving clubs, when the three were swept away by fast running water and drowned in the low air-space (or "duck", (which was flooded to the roof on this particular occasion) section of passage between the end of Lower Cradle Hole and the Grand Gallery in Marble Arch Cave.[21] Those killed were Philip Marshall (20), Brian Patrick Kennedy (22) and Conleth Cormican (21).[22][23]
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.[24]
In 2009 and 2010, diving connections were made to nearby cave systems byArtur Kozłowski. Kozłowski made the first connecting dive to Prod's Pot – Cascades Rising, doubling the total length of the system from 4.5 to 9 km (2.8 to 5.6 mi).[25] Subsequently, he and Chris Jewell connected the newly established Monastir Sink – Upper Cradle system,[26] extending the Marble Arch system to 11.5 km (7.1 mi).[27] The discoveries make this the longest cave in Northern Ireland.[2]
The Marble Arch Cave system is chieflyformed from three rivers which drain off the Marlbank area on the north side of Cuilcagh mountain. From west to east, thesetributaries are the Sruh Croppa, the Aghinrawn (or Monastir) and theOwenbrean.[NB 1][7]
The Prod's Pot – Cascades Rising section of the system (connected to Marble Arch Caves in 2009)[25] has a complexhydrology which includes drainage from at least five small sinks on the eastern Marlbank (Gortmaconnell Pot, Little Gortmaconnell Pot, Smokey Mountain Sink and two unnamed sinks at Brookfield have beendye traced to Cascades); sections of the Owenbrean River upstream of its main sink at Pollasumera; and most notably Goat Pot, Aghatirourke Pot,Pigeon Pots andBadger Pot on East Cuilcagh, nearly 3 kilometres (1.9 mi) to the southeast.[28]Of these, Goat Pot and Aghatirourke Pot have also been traced to Tullyhona Rising (1.5 kilometres (0.93 mi) east-southeast from Cascades Rising); Pigeon Pots, Badger Pot and Aghatirourke Pot also flow to Gortalughany Rising (an overflowrising on East Cuilcagh); and Badger Pot and Pigeon Pots also flow toShannon Pot on the far western slopes of Cuilcagh.[29]
Édouard-Alfred Martel first postulated that Marble Arch Cave would make a worthyshow cave after initially exploring the system in 1895.[10] However, it was not until 1982 that work eventually began on creating a new undergroundtourist attraction.[30] Development included:
Covering a section of the main stream passage of the system, the Marble Arch Caves show cave was opened to the public on 29 May 1985.[30] Visitors travel through the first part of the caves by boat on the subterranean Cladagh River, before walking through the rest of the chambers.[31]
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Between 1985 and 2008, the show cave attracted approximately 1 million visitors, from 100 countries worldwide.[32] Annual visitor capacity (during the period that the cave is open, March–September) is 94,060.[20]
In 2001, the caves and the nearbyCuilcagh Mountain Park joined to become a European Geopark under the name Marble Arch Caves European Geopark, the first park in theUK to be recognised by theEuropean Geoparks Network (EGN).[31] This allocation was due in part to the existence of the caves themselves and also the rareblanket bog which covers a vast area of the mountains. Under an agreement between the EGN and theUNESCO Earth Sciences division in 2004,[33] the park became part of theGlobal Network of National Geoparks (GGN) scheme and was renamedMarble Arch Caves Global Geopark. In 2008, the park boundaries were extended across theborder into parts ofCounty Cavan in theRepublic of Ireland, making it the first international Geopark in the world.[34]
The cutting ofturf has led to damage in the area. Extensivedrainage in parts of the bog has damaged the bog's ability to retain water, resulting inflooding and abnormally high water levels in the caves downstream.[36][37] This has impeded tourist activity in the past, notably in 1989 when the impact of such damage influencing cave water levels first became evident.[36] As a protective measure, turf cutting has been banned within the wider Geopark. In addition more than 1200 smalldams have been put in place across the bogland to slow water flow and encourage the growth of new bog.[38]
Another problem is that human interference can cause the limestone to be damaged oreroded. In a particular case in 1984, a group of vandals broke into the show cave before it was opened to the public and threw stones at some of thecalciteformations around the entrance. Many smallstalactites were snapped off at their bases, while the tip of the largest stalactite in the show cave (over 2 metres [6.6 ft] in length)[35] was broken off. This tip fell onto asandbank on the cave floor where it was retrieved the next day by a workman. It was then sent to theUlster Museum inBelfast where a calciteresin was specially produced and subsequently used to stick the tip back onto its original position.[39]
Geomorphological knowledge of the Marble Arch Upland and indeed of all the other upland karst in this part of Ireland is exceedingly poor which is surprising since the karst is among the finest in the British Isles.[5]
54°15′30.34″N7°48′51.53″W / 54.2584278°N 7.8143139°W /54.2584278; -7.8143139
