The BGS Lexicon of Named Rock Units — Result Details
Tavy Formation
| Computer Code: | TVY | Preferred Map Code: | Tvy |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Frasnian Age (DR) — Famennian Age (DA) | ||
| Lithological Description: | Pale green and grey-green slaty silty mudstone with minor thin fine-grained sandstone beds and lenses. Medium- to fine-grained sandstone interbedded with mudstone and laminated siltstone constitute the Trehills Member. | ||
| Definition of Lower Boundary: | A transition into the Torpoint Formation. Pale green slaty mudstone of the Tavy Formation passing into purplish red slaty mudstone of the Torpoint Formation. | ||
| Definition of Upper Boundary: | A transition between the Tavy Formation and the Burraton Formation (grey slate) is observed in the vicinity of North Hooc Mine [4254 6608], and Holes Hole [425 655] in an inverted sequence. | ||
| Thickness: | Not known. | ||
| Geographical Limits: | Defined on Sheet 348 but similar lithologies occur on: 335/336 (Tredom Slate Formation), 337 (Kate Brook Slate Formation), 338 and 339 (Kate Brook Slate Formation), 349 (Upper Devonian Slate). | ||
| Parent Unit: | Tamar Group (TAMA) | ||
| Previous Name(s): | Tredorn Beds [Obsolete Name and Code: Use TSL, TVY]
(-4939)
Tredorn Phyllites [Obsolete Name and Code: Use TSL, TVY] (-4940) Kate Brook Succession [Obsolete Name and Code: Use TVY] (-4377) Delabole Slates [Obsolete Name and Code: Use UDSL, TVY, DLBS, TSL] (-3996) Woolgarden Slates [Obsolete Name And Code: See TVY] (WSL) Penpethy Beds [Obsolete Name and Code: Use DLBS, TVY] (-2152) Kate Brook Slate [Obsolete Name And Code: See TVY] (KBSL) Woolgarden Phyllite [Obsolete Name and Code: Use TVY, TSL] (-2506) Cann Wood Slate Formation [Obsolete Name and Code: Use TVY] (-3099) Halwell Cottage Beds [Obsolete Name and Code: Use TVY] (-3100) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Reference Section | River cliff, inverted sequence and transitional top of Formation at Holes Hole. | ||
| Reference Section | River cliff at Weir Point containing a transitional boundary between the greenish grey slatey mudstone of the Tavy Formation and the purplish red silty mudstone of the Torpoint Formation. | ||
| Partial Type Section | River cliff. Tavy Bridge to Hole's Hole. | ||
| Partial Type Section | River cliff. Warleigh Quay to Potters Bridge. | ||
| Partial Type Section | River cliff. Tavy Bridge to Whittacliffe Wood. | ||
| Reference(s): | |||
| Parkinson, J, 1903. On the geology of the Tintagel and Davidstow district, Quarterly Journal of the Geological Society,Vol.59,408-421. | |||
| Waters, R A, 1970. The Variscan structure of eastern Dartmoor. Proceedings of the Ussher Society, Vol.2, 191-197. | |||
| Selwood, E B, Edwards, R A, Simpson, S, Chesher, J A, Hamblin, R J O, Henson, M R, Riddolls, B W and Waters, R A. 1984. Geology of the countryside around Newton Abbot. Memoir of the British Geological Survey, Sheet 339 (England and Wales). | |||
| Leveridge B E, Holder, M T, Goode, A J J, Scrivener R C, Jones N S and Merriman, R J. 2002. Geology of the Plymouth and south-east Cornwall area. Memoir of the British Geological Survey, Sheet 348 (England and Wales). | |||
| Dewey, H, 1909. On Overthrusts at Tintagel (North Cornwall). Quarterly Journal of the Geological Society, Vol.65, 265-280. | |||
| Chandler, P and McCall, G J H, 1985. Stratigraphy and structure of the Plymouth-Plymstock area: a preliminary revision. Proceedings of the Ussher Society, Vol.6, 253-257. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E335 E336 E339 E337 E348 E338 E349 | |||