Photos • Location
Closer view of the rock formation
| South Stack Formation | |
|---|---|
|
Stratigraphic range:
Furongian-
Tremadoc ~ | |
 Folded metamorphosed sandstones of the South Stack Formation | |
| Type | Geological formation |
| Unit of | Holy Island Group |
| Underlies | New Harbour Group |
| Overlies | not exposed |
| Thickness | ~360–1,000 m (1,180–3,280 ft) |
| Lithology | |
| Primary | Metamorphosed sandstone |
| Other | Metamorphosed mudstone |
| Location | |
| Coordinates | 53°18′N 4°41′W / 53.300°N 4.683°W |
| Region | Holy Island, Anglesey |
| Country | 
Wales |
| Type section | |
| Named for | South Stack |
  South Stack Formation (the United Kingdom)  South Stack Formation (Wales) | |
The South Stack Formation is a sequence of Cambro- Ordovician ( Furongian to Tremadocian) metasedimentary rocks exposed in northwestern Anglesey, North Wales. [1] The outcrop of this formation at South Stack was chosen as one of the top 100 geosites in the United Kingdom by the Geological Society of London, for its display of small-scale folding. [2]
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References
- ^ "South Stack Formation". The BGS Lexicon of Named Rock Units. British Geological Survey. Retrieved 13 October 2014.
- ^ "The Geological Society's 100 Great Geosites". The Geological Society. 2014. Retrieved 14 October 2014.
Further reading
- Phillips, E, 1991. Progressive deformation of the South Stack and New Harbour Groups, Holy Island, Western Anglesey, North Wales. Quarterly Journal of the Geological Society, Vol.148, p. 1091-1100
- Shackleton, R M, 1954. The structure and succession of Anglesey and the Lleyn Peninsula. British Association for the Advancement of Science, Vol.11, p. 106-108
- Greenly, E. 1919. Geology of Anglesey. Memoir of the Geological Survey, UK
- Blake, J F, 1888. The Monian System of rocks. Quarterly Journal of the Geological Society, Vol.44, p. 476-480