Fan Fraith is a top of

Fan Gyhirych Fan Gyhirych is a mountain in the Fforest Fawr section of Brecon Beacons National Park in south Wales. It lies within the county of Breconshire, and administered as part of the unitary authority of Powys Powys ( , ) is a Principal a ...

in the

Fforest Fawr Fforest Fawr (, ) is an extensive upland area in the county of Powys, Wales. Formerly known as the Great Forest of Brecknock in English, it was a royal hunting area for several centuries but is now used primarily for sheep grazing, forestry, wate ...

section of the

Brecon Beacons National Park Brecon Beacons National Park, officially named Bannau Brycheiniog National Park (), is a National parks of the United Kingdom, national park in Wales. It is named after the Brecon Beacons (), the mountain range at its centre. The national park ...

in the county of

Powys Powys ( , ) is a Principal areas of Wales, county and Preserved counties of Wales, preserved county in Wales. It borders Gwynedd, Denbighshire, and Wrexham County Borough, Wrexham to the north; the English Ceremonial counties of England, ceremo ...

, south

Wales Wales ( ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by the Irish Sea to the north and west, England to the England–Wales border, east, the Bristol Channel to the south, and the Celtic ...

. Its summit is at a height of 2192 feet or 668 m. It lies within

Fforest Fawr Geopark Fforest Fawr Geopark is a Geopark in the Brecon Beacons National Park, south Wales. It is the first designated Geopark in Wales having gained membership of both the European Geoparks Network and the UNESCO-assisted Global Network of National G ...

Geology

The bulk of the hill is formed from

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

s and

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, ...

s of the Brownstones Formation of the

Old Red Sandstone Old Red Sandstone, abbreviated ORS, is an assemblage of rocks in the North Atlantic region largely of Devonian age. It extends in the east across Great Britain, Ireland and Norway, and in the west along the eastern seaboard of North America. It ...

laid down during the

Devonian period The Devonian ( ) is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at million years ago ( Ma), to the beginning of the succeeding C ...

. Sandstones of the overlying Plateau Beds Formation occur in the summit area as do beds of the Grey Grits Formation - both are assigned to the upper Devonian. The Plateau Beds sandstones occur across the whole southern aspect of the mountain and are often present as boulder fields,a result of

periglacial Periglaciation (adjective: "periglacial", referring to places at the edges of glacial areas) describes geomorphic processes that result from seasonal thawing and freezing, very often in areas of permafrost. The meltwater may refreeze in ice wedg ...

activity. Several geological faults affect these rocks, the most significant of which is the northeast-southwest aligned Swansea Fault, a part of the

Cribarth Disturbance The Cribarth Disturbance is a geological structure forming a lineament which stretches across south Wales from Swansea up the Swansea Valley then northeastwards to Brecon and beyond. It consists of both a series of faults and associated folds wh ...

.British Geological Survey 1:50,000 map sheet 231 'Merthyr Tydfil' & accompanying memoir

Access

The hill is entirely within access land and freely available to walkers. A private vehicular track which runs over the southeastern shoulder of neighbouring

affords the easiest and most commonly used ascent of Fan Fraith.

References

{{Reflist

External links

images of Fan Fraith & surrounding area on Geograph website
Mountains and hills of Powys Fforest Fawr Nuttalls