The BGS Lexicon of Named Rock Units — Result Details

Tintagel Volcanic Formation

Computer Code: TVF Preferred Map Code: notEntered
Status Code: Full
Age range: Visean Stage (CV) — Visean Stage (CV)
Lithological Description: Poorly sorted green fine-to coarse-grained basaltic calcareous tuffs with subordinate agglomerates and recrystallised carbonate-rich basaltic lavas. A few thin pink limestones occur scattered throughout the Formation.
Definition of Lower Boundary: The lower boundary is taken at the sharp contact of tuffs, lavas and agglomerates of the Tintagel Volcanic Formation with the siltstone-striped mudstones of the underlying Barras Nose Formation.
Definition of Upper Boundary: The upper boundary is taken at the sharp contact of the finely banded dark to pale grey mudstones with thin siltstones of the overlying Trambley Cove Formation with the tuffs, lavas and agglomerates of the Tintagel Volcanic Formation.
Thickness: To 90m
Geographical Limits: Tintagel area (SX 06 89) to south of Launceston (SX 32 77), Cornwall.
Parent Unit: Teign Valley Group (TEVY)
Previous Name(s): Volcanic Series (-1877)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Crags on the north side of the road leading to the beach at Trebarwith Strand, 2km south of Tintagel, north Cornwall. Section exposes about 70m of tuffs with subordinate agglomerates overlying the mudstones of the Barras Nose Formation. Basal contact seen but upper contact not seen. 
Type Area  Cliff sections around Tintagel. Freshney, E C, McKeown, M C and Williams, M, 1972. 
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). 
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). 
Parkinson, J, 1903. On the geology of the Tintagel and Davidstow district, Quarterly Journal of the Geological Society,Vol.59,408-421. 
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). 
Dewey, H, 1909. On Overthrusts at Tintagel (North Cornwall). Quarterly Journal of the Geological Society, Vol.65, 265-280. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E322 E336 E337