The BGS Lexicon of Named Rock Units — Result Details
Newton St Cyres Breccia Formation
| Computer Code: | NSBR | Preferred Map Code: | NSBr |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Permian Period (P) — Permian Period (P) | ||
| Lithological Description: | Reddish brown, mainly fine-grained breccia; clasts (mostly < 5cm) of shale, slate, hornfels, chert, potassium feldspar (murchisonite), vein quartz, quartz-porphyry, acid lava and tuff, microgranite and tourmalinised igneous rocks. Locally well cemented. Local sandstone beds. Sub-vertical sandstone bodies. | ||
| Definition of Lower Boundary: | Correlates with Heavitree Breccia of Exeter area. Rests on Crediton Breccia, locally with a scarp at the junction. Distinguished from Crediton Breccia by more sandy matrix, greater degree of cementation and presence (increasing towards the top) of potassium feldspar (murchisonite). | ||
| Definition of Upper Boundary: | Passes gradationally upwards and laterally into the Shute Sandstone. | ||
| Thickness: | 180m southwest of Newton St Cyres, 10m at Creedy Barton (SX 865 995). | ||
| Geographical Limits: | Present in the eastern Crediton Trough around the limbs of a synclinal structure from Newton St Cyres in the south, to Trobridge House. [SX 835 979] in the west, to near Shute [SS 890 001] in the north. | ||
| Parent Unit: | Exeter Group (EXE) | ||
| Previous Name(s): | St Cyres Breccias [Obsolete Name and Code: Use NSBR]
(-4229)
St Cyres Beds [Obsolete Name and Code: Use NSBR] (-2344) |
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| Alternative Name(s): | Heavitree Breccia [Obsolete: use HVBR] |
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| Stratotypes: | |||
| Type Area | Road cuttings in Newton St Cyres to east and west of the village. | ||
| Reference(s): | |||
| Scrivener, R C. 1988. Geology of the Newton St Cyres district (Devon). 1:10,000 Sheet SX89NE. British Geological Survey Technical Report, WA/88/5/ | |||
| Laming, D J C, 1982. The New Red Sandstone. "In" Durrance, E M and Laming, D J C, (Editors). The Geology of Devon, p.148-177. | |||
| Edmonds, E A, Wright, J E, Beer, K E, Hawkes, J R, Fenning, P J, Freshney, E C, Lovelock, P E R, McKeown, M C, Ramsbottom, W H C and Williams, M. 1968. Geology of the country around Okehampton. Memoir of the Geological Survey of Great Britain, Sheet 324 (England and Wales). | |||
| Hutchins, P F, 1963. The Lower New Red Sandstone of the Crediton Valley. Geological Magazine, Vol.100, 107-128. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| none recorded or not applicable | |||