The BGS Lexicon of Named Rock Units — Result Details

Tredorn Slate Formation

Computer Code: TSL Preferred Map Code: TSl
Status Code: Pending Upgrade
Age range: Famennian Age (DA) — Famennian Age (DA)
Lithological Description: Greenish grey quartz-chlorite-mica slate, locally interbedded with thinly bedded, commonly lenticular bioclastic limestone and dolomite beds, up to 0.15m thick, and with sandstone, siltstone and rare tuff beds.
Definition of Lower Boundary: Faulted.
Definition of Upper Boundary: Faulted.
Thickness: 500-800m (estimated structural thickness).
Geographical Limits: From Tregardock to south of South Petherwin, north Cornwall.
Parent Unit: Tamar Group (TAMA)
Previous Name(s): Tredorn Beds (-4939)
Tredorn Phyllites (-4940)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Tredorn area, north Cornwall. Selwood, E B, et al, 1998. 
Reference(s):
Selwood, E B, Thomas, J M, Williams, B J, Clayton, R, Durning, B, Smith, O and Warr, L N, 1998. Geology of the country around Trevose Head and Camelford. Memoir of the British Geological Survey, sheets 335 and 336 (England and Wales). 
Freshney, E C, McKeown, M C and Williams, M. 1972. Geology of the coast between Tintagel and Bude. Memoir of the Geological Survey of Great Britain, part of sheet 322 (England and Wales). 
McKeown, M C, Edmonds, E A, Williams, M, Freshney, E C and Masson Smith, D J. 1973. Geology of the country around Boscastle and Holsworthy. Memoir of the British Geological Survey, sheets 322 and 323 (England and Wales). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E322 E336 E337