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Summary Full report
Boho; Boho Caves Sink
Rec. Number:385File Number: H14
Locality Type:Cave Status: PASSI
Grid Reference: H12684431 Not Entered
County: Fermanagh District:Fermanagh District Council
Period:Quaternary, Carboniferous
Stages:Asbian, Holocene, Visean
Lithostrat:Dartry Limestone Formation
Site Description
The Boho Cave System is an extensive horizontal joint controlled maze cave developed in the Cherty Facies of the Dartry Limestone. The joint sets are approximately at right angles, one oriented N-S and the other E-W. In the area of Boho Caves the bedding dips gently to the west. Fissures in both main orientations have been enlarged, but the N-S development predominates. All the passages in the system are characterised by chert bands which in many areas have been etched, leaving them as protruding ledges.
There are at least seven entrances to the main areas of cave but the Quarry Entrance and the episodic sink of the Aghanaglack River are the largest and are those commonly used to gain access to the system.
From the episodic sink there are a number of constricted routes leading north into a series of fossil chambers (Formation Passage and Coleraine Chamber) which contain the best calcite speleothems in the system. There are good examples of straws, stalactites, stalagmites, soft calcite, flowstone, curtains, gour pools and canopies which are developed on roof, walls and on a floor of medium to fine clastic sediment infill. Some flowstone canopies have sandstone pebbles cemented into exposed undersides. Coleraine Chamber is a large breakdown area and through the boulders of the floor the episodic zone can be reached. To the west Flush Passage and the Sewerage System are also part of the episodic zone and there are some breakdown chambers such as Henry's Hall.
The main open passage from the episodic sink leads via fine phreatic tubes, areas of pebble and cobble banks and cherty rifts to the Quarry Entrance, which is the flood rising. This route takes a large amount of the flow during flood. To the south is a complicated area of opened cross joints leading to the Field Shakeholes and the Southern Series, while to the north of the main passage lies the Virgin Circuit. This area has another group of breakdown chambers which are inundated during flood.
Organic debris gathers among the breakdown which chokes the chamber floors and fine sediment banks are also present in which charcoal layers are seen. A number of enlarged joints are now infilled with clastic sediments. Soft calcite deposits are common in the Virgin Circuit chambers and there are also gour pools, straw stalactites and a number of other speleothem deposits.
In the Ravine are two short sections of cave, the Upper and Lower Ravine Caves.

Boho Cave Sink is a feature of the Boho Cave System of the Belmore, Ballintempo and Tullybrack Uplands.

For general information on the systems and features of the Boho Caves, including this one, and a reference list, see site description 'Belmore, Ballintempo & Tullybrack Uplands; Boho'.

Minerals:No data
Rocks:Chert, Limestone
FossilGroups:No data
Fossil List:
Relations:No Data
Geomorph:cave, sinkhole
Length:No dataWidth:No dataHeight:No data
Depth:No dataArea:No data  
Approach:Not entered
Restrictions:Not entered
Management:The Boho Quarry and Ravine are owned and managed by Fermanagh District Council. The upstream episodic sink entrance has been modified by the installation of a flood debris grill as part of a water course management programme. There is also a dam at this sink which is presumed to have been built as a silt trap for commercial use or for water course management. The Fermanagh Environmental Impact Group undertook a rubbish removal programme in the Ravines and cave, a refencing of the site and some minor woodland management, during the early 1990's, which has largely restored the quality of the site. Both the Boho Caves area and Pollnagollum Coolarkan are accessible to casual visitors and are promoted in some tourist guide books as sites of interest. There is also an aspiration in the local community to 'develop' the caves for visitors. There are both conservation and safety implications in such proposals. Internal threats: The episodic passages of the Boho Caves can be classified as high energy and the relict areas as medium to low energy. The main high energy passages are regularly used by education and adventure caving groups but as the access to the speleothem rich abandoned areas is via tight cave passage these groups do not visit them. The flood inundation has brought household and farm debris into the cave in the past but the problem is not as significant today. The easily accessible passages from the Quarry Entrance to the Main Sink has suffered graffiti from casual visitors in the form of large painted arrows on the cave walls. Pollnagollum Coolarkan is medium to high energy cave passage and is also regularly used by caving groups. As the passage is easily accessible, relatively easy and short (and the small areas of speleothems are generally out of reach) the cave provides a good facility for speleological education. External threats: It appears that large scale dumping of rubbish in the Ravine at Boho has stopped, however, debris dumped in the river above the cave system is washed into the cave. The flood debris grill, which is cleared regularly, stops the majority of large items. There are a number of houses and roads directly above the Boho Cave system and there are numerous houses, farms and large areas of forestry in the catchment. Leaching of effluent above the caves could affect the speleothems in the abandoned areas and the water quality in the cave. Effluent discharged into the river and drainage changes in the catchment could also affect the cave. Sporadic quarrying activity at Coolarkan Quarry still takes place and should the face closest to the doline be worked there would be a threat to the site. Aghanaglack Cave has been blocked during construction of a private road and is inaccessible.
Uses:Not entered
Potential:Not entered
Educ. Level:Not entered


None entered

Map No:None entered
Rec Type ESCR report Recorder:  
Enterer: Doughty, P.J.
Updates: 12 Jun 2004 / 10 Apr 2004 / 27 FEB 97 / 26 DEC 96 / 18 NOV 96 / 17 JAN 96 / 16 JAN 96
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