The BGS Lexicon of Named Rock Units — Result Details
Rora Mudstone Formation
| Computer Code: | RRAM | Preferred Map Code: | notEntered |
|---|---|---|---|
| Status Code: | Pending Upgrade | ||
| Age range: | Famennian Age (DA) — Tournaisian Age (CT) | ||
| Lithological Description: | Purple, green and greyish green mudstones. Scattered siliceous and calcareous nodules developed at some levels. A prominent 10m-thick unit of buff-weathering calcareous laminated siltstone capped by 2m of interbedded grey silty mudstones and siliceous black mudstones is present at the top of the Formation. | ||
| Definition of Lower Boundary: | The lower boundary is not seen. May possibly overlie the Tavy Formation but further investigation is needed. | ||
| Definition of Upper Boundary: | The upper boundary is taken at the sharp incoming of the black mudstones of the "Ararat Slate" (Teign Chert Formation) above the buff-weathering calcareous laminated siltstones capped by 2m of interbedded grey silty mudstones and siliceous black mudstones at the top of the underlying Rora Mudstone Formation. | ||
| Thickness: | Uncertain, but probably not more than 200m exposed. | ||
| Geographical Limits: | Liverton area (SX79 75), south Devon. | ||
| Parent Unit: | Tamar Group (TAMA) | ||
| Previous Name(s): | Rora Slate Formation [Obsolete Name And Code: Use RRAM]
(RSL)
Islington Slates [Obsolete Name and Code: Use RRAM] (-2402) Rora Slate [Obsolete Name and Code: Use RRAM] (-2403) Liverton Slates [Obsolete Name and Code: Use RRAM] (-3646) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Partial Type Section | South Rora Down Quarry, southwest of Liverton, south Devon. 2m of green and purple mudstones with a thin bed of black siliceous mudstone is exposed in the upper part of the Formation. Neither the base nor the top of the Formation is seen. | ||
| Reference(s): | |||
| Bristow, C M. 1963. The geology of the area between Islington, Liverton and Bickington. Proceedings of the Ussher Society, Vol. 1, 65-67. | |||
| 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). | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| none recorded or not applicable | |||