| Site Type: | Karst | | Site Status: | ASSI | | Council area: | Fermanagh & Omagh District Council | | Grid Reference: | H0948 | | Bing maps: | 54.38102,-7.86147 | | Google maps: | 54.38102,-7.86147 | | Rocks |
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| Rock Age: | Quaternary, Carboniferous (Asbian, Holocene, Visean) | | Rock Name: | Dartry Limestone Formation, Glenade Sandstone Formation, Glencar Limestone Formation, Knockmore Limestone Member, Meenymore Formation | | Rock Type: | Breccia, Chert, Limestone, Mudstone | | Interest |
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| Minerals: | Calcite | | Fossil Groups: | Coral | | Other interest: | bedding, fault, joints, slickensides, breakdown, cave, cave pearls, clastic sediments, column, dendritic river cave, doline, drift, dry valley, flowstone, gour pool, helictite, limestone pavement, organic sediments, sinkhole, speleothem, stalactite, stalagmite, straw, sump, varve |
| Summary of site: |
| The Noon’s Hole/Arch Cave system is part of the remarkable escarpment on the east side of the Glenade Sandstone uplands. It is situated immediately south of the Knockmore/Pollaraftra catchment, with the Reyfad catchment to the south and the Boho Cave area beyond that. | | Noon’s Hole to Arch Cave (see separate site description) is considered one of the best cave traverses in the British Isles. It incorporates the finest and deepest pothole in Ireland, exceeding 80m depth and, with over a kilometre of expansive and highly decorated passageway, an open dive through two phreatic sections in the Arch system and an expansive exit through the broad span of the eponymous arch, it offers a truly memorable caving and scientific experience. | | The catchment for the system is small, around 3.5km², because fronting the east facing escarpment of the Glenade Sandstone uplands that dip to the west, the bulk of the drainage is to the west through Big Dog Forest. There are, however, a small number of streams that flow off the sandstone and the Meenymore Formation rocks immediately below them on to the Dartry Limestone, where they sink. Most of this water is believed to enter the main Noon’s Hole/Arch Cave system to emerge at the Arch Cave resurgence at the base of the Dartry Limestone where it is in contact with the underlying Glencar Limestone. A series of cascades follows in the descent to the Screenagh River. | | There are a few other caves and potholes in the area of which only Pollanaffrin is significant. There are at least four small stream sinks which possibly feed water into Noon’s Hole, but no dye testing to prove the connections has yet been conducted. | | The upper of the two benches on the scarp face is a continuation of the fine limestone pavement mentioned in the Pollaraftra general description, and in this area the limestones include silicified fossils. | | There is a rich surface karst in the area, with dolines, potholes, dry valleys (with periodic streams), open resurgences and boulder strewn cascades, but no hint in the landscape of what lies beneath. The three dry valleys in this area probably date from the permafrost phase at the close of the final stage of the last glaciation (about 10,000 years ago) when meltwater coursed over the deeply frozen ground and maintained surface flow. As the rock gradually warmed, water in the joints and bedding planes melted and they were freed to take water until eventually they enlarged into underground courses. There is much evidence of glaciation in this general area. | | There is already environmental damage to the site caused by the indiscriminate dumping of agricultural and household refuse into Noon’s Hole and elsewhere. High flood conditions sweep it into the system and although much of it passes through to emerge at Arch Cave, light materials such as polystyrene tend to strand as unsightly blemishes throughout the system. Cattle and human effluent are also major problems. A local management scheme is essential for this nationally important karst area. | | Noon’s Hole is so named because the remains of Dominic Noon were recovered from the first ledge in the main shaft sometime in the 1820s. Noon joined an outlawed nationalist agrarian reform group known as the ‘Ribbon Men’ but acted as an informer to the authorities; it was on his evidence that a number of local men were transported to Australia. Always a popular figure in the area, particularly for his outstanding singing and dancing abilities, he was invited to a ‘wedding party’ to perform. It was a trap and, despite his police protection, he was kidnapped and hidden in a cottage in the uplands above Boho where he may have had his tongue cut out (his skull was so severely crushed that the mutilation could not be confirmed). From there he was taken to the Noon’s main shaft and thrown down. It was several days later, after rumours that his body had been thrown into a hole, that a local quarryman was lowered on a rope and Noon’s fate was confirmed. The murderer(s) was never identified. |
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