The BGS Lexicon of Named Rock Units — Result Details

Roseland Breccia Formation

Computer Code: RDBR Preferred Map Code: RBr
Status Code: Pending Upgrade
Age range: Givetian Age (DV) — Frasnian Age (DR)
Lithological Description: [Olistostrome] Grey slaty mudstone with framework and matrix breccias/conglomerates, interbedded sandstone, felsic and mafic tuffs/lavas and metamorphic rock breccias. Olistoliths of Ordovician quartzite, Silurian and early to mid Devonian limestone, sandstone, breccia, metamorphic and mafic/ultramafic igneous rocks.
Definition of Lower Boundary: No details yet provided.
Definition of Upper Boundary: Dodman Thrust.
Thickness: To 1.5km
Geographical Limits: Roseland and Meneage, south Cornwall.
Parent Unit: Gramscatho Group (GRO)
Previous Name(s): Roseland Volcanics [Obsolete Name And Code: Use RDBR] (RSV)
Meneage Olistostrome [Obsolete Name: Use RDBR] (MENO)
Veryan Series (-1780)
Meneage Formation (-486)
"Meneage Crush Zone" (-3634)
Grampound Grit [Obsolete Name And Code: Use TRSA Or GRAD] (GPG)
Roseland And Meneage Breccias (-1136)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Gerrans Bay and Veryan Bay sections, south Cornwall. 
Reference(s):
Holder, M T and Leveridge, B E, 1986. A model for the tectonic evolution of south Cornwall. Journal of the Geological Society, London, Vol.143, 125-134. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E353 E354