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Outdoor Activity Links:
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Brecon
Beacons Guide to Outdoor Activities Caving
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Beacons Tour Operators Outdoor
Adventure Centres in the Brecon Beacons
Geology and Cave Creation:
The Brecon Beacons National Park encompasses some of the most
important cave systems in Europe. There are many outdoor centres and specialists in the
Brecon Beacons which offer caving courses suitable for the beginner and the more
experienced caver. However, be mindful that caving can be dangerous and you should not
consider visiting any cave without a qualified instructor. Some of the more extensive cave
systems can only be accessed with the prior permission of local caving clubs. Their
experience can be invaluable.
This southern edge of the Brecon Beacons National Park contains a
belt of carboniferous limestone wedged between Old Red sandstone to the north
and the Millstone Grit containing coal deposits to the south. . A narrow belt on the
southern rim of the national park boundary consists of a Carboniferous Limestone
outcrop. To the north of this belt can be found the mountainous outcrops of Old
Red Sandstone which form the main upland region of the national park reaching
above 600
metres high. Although the altitude reached by the Carboniferous Limestone rim is
significantly lower the landscape has a distinctive appearance
and character of its own which makes it equally fascinating for the visitor and
geologist. The Carboniferous Limestone within the Brecon Beacons National Park
were in all probability deposited more than 300 million years ago. Limestone is
a rock consisting mainly of calcite and is often of organic origin.
One of the
characteristics of limestone is that it is soluble in water and this
particular mountain range rarely lacks water. Significant levels of rainfall are further enhanced by
the predominantly southwards drainage of water from the Old Red Sandstone
mountain range to the north. This gives rise to a karst landscape which
often has a deep layer of peat on the surface holding water throughout the year
and where the surface drainage does not dispose of all the water collected.
This in turn leads to the development of underground drainage routes evolved
over geological time in the cracks and fissures of the soluble limestone.
One of the characteristics of carboniferous limestone is that it is
susceptible to the action of slightly acidic water. Rain falling in this
locality absorbs carbon monoxide from the air thus creating a mild
solution of carbonic acid. As this slightly acidic water passes through
the naturally occurring cracks and fissures in the carboniferous limestone
over geological time it has created
some of the most important cave systems in Europe.
Public Access and Safety:
The extensive
cave systems in the Brecon Beacons are only accessible to the experienced
caver and only then with local knowledge or the assistance of a guide with
local knowledge. however, two opportunities exist for members of the
public to experience this aspect of the Carboniferous limestone geology on
the southern edge of the national park.
-
Porth
yr Ogof is the largest cave
entrance in the national park and is within a short walking distance
from an adjacent car park albeit via a steep uneven twisting path.
Visitors should not attempt to venture further than the immediate
entrance of the cave Particular care should be taken during or
following heavy rainfall as the cave entrance becomes quickly flooded
and the foot paths leading to the cave are especially hazardous when
wet.
-
Just north of
the Abercrave the
National Show Caves at Dan yr Ogof are one of the most popular
visitor attractions in national park. This is an extensive cave
system of which some of the major caves including the spectacular
"Cathedral Cavern" are open to the public. This very popular
visitor attraction a range of other items of interest including a
Dinosaur Park, Iron Age Farm, Shire Horses, and much more. This is the safest
opportunity for visitors to taste a cave system.
There are many outdoor
centres and specialists in
the Brecon Beacons which offer caving courses suitable for the beginner
and the more experienced caver. However, be mindful that caving can be
dangerous and you should not consider visiting any cave without a
qualified instructor. Some of the more extensive cave systems can only be
accessed with the prior permission of local caving clubs. Their experience
can be invaluable. Please make sure to visit our Outdoor Activities Advisory Page and
consider carefully the advice offered on the page in respect of making sure that
any outdoor activities provider is suitably qualified, registered and
experienced. Listing on this page is not an endorsement or otherwise of any
kind.
Ogof Ffynnon Ddu:
On the hillside above Craig y Nos country park,
north of Abercrave, can be found the headquarters of the South Wales
Caving Club. Impressively located in a long terraced role of form a
quarry workers cottages, this is the base of one of the largest caving
clubs in the country. It is located here because near by is a major
underground cave system which is one of the most complex and the deepest
in Britain - Ogof Ffynnon Du - which roughly translates as the spring
emerging from the black cave. The largest cave passage in Britain referred to
as The Time Machine can be found within Ogof Darren Cilau.
This particular
passage is more than 30 m high and of a similar width.
The Black Mountains:
There are three cave systems in the eastern section
of the national park which are well worth a mention.
The Llangattock
Escarpment which dominates the
landscape above the Usk Valley as it continues its journey south from
Crickhowell is particularly noteworthy and for further information
please continue to the following page -
Llangattock Escarpment.
The
Clydach Gorge has numerous cave passages
most of which are of little general interest. An experienced caver
seeking specialised information on this locality would be best advised
to get in touch with one of the local caving clubs or to consult the
field guide mentioned in the publications list at the foot of this page.
However, the resurgence at Pwll y Cwm is of interest to the general
visitor is well as the caver. The resurgence at Pwll y Cwm takes the
form of a pool which is much deeper than its appearance would suggest.
It is a significant exit sump from the Ogof Daren
Cilau cave system which starts at the
Llangattock Escarpment.
Black Mountain:
Dan yr Ogof is the only major cave system so far
discovered in the western part of the national park known as the Black
Mountain. This extensive cave system has more than ten miles of passages
that have been explored with many other passages awaiting exploration and
discovery. in 1912 to local men, Tommy and Jeff Morgan, decided to explore
the cave entrance from which the river Llynfell emerged from a resurgence
at the base of a cliff face. Their initial exploration of the cave
ended when they reached a large underground lake. They returned to
continue their exploration crossing the first lake and three others using
a coracle which was small and light enough for their purposes. Further
exploration of this extensive cave system did not make progress until 1963
when Eileen Davies, a local member of the South Wales Caving Club managed
to crawl through a tight passageway that had defeated earlier explorers.
Visitors to the show cave enter through a mined tunnel which gives access
to a number of the areas originally discovered by the Morgan brothers
including the large Cathedral Cave which is 10 m high at one point.
Walker's on the mountain above Dan
yr Ogof are likely to encounter a large sink hole at SN 811180. Sinc y
Giedd is the principal sink for the Dan yr Ogof cave system. This narrow
deep valley set amongst rather barren moorland gathered surface water and
directed it into the underground cave system.
No major cave system has been discovered in the
limestone area in the far west of the national park. However, there
are a number of lesser features worth noting.
Carreg Cennen Castle is located on
top of a outstanding limestone crag and the construction of the Castle has
incorporated a natural cave passage which may have served as a water
supply for the occupants.
Afon Llwchwr emerges dramatically from the limestone at
a major resurgence located at S. N. 669 178.
Further
Information:
Links:
Local Caving Links:
UK Caving Equipment and Shops:
Disclaimer:
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