The BGS Lexicon of Named Rock Units — Result Details

Robinson Member

Computer Code: RNM Preferred Map Code: RNM
Status Code: Full
Age range: Arenig Series (OR) — Arenig Series (OR)
Lithological Description: A series of large sandstone-rich olistoliths ranging in size up to 1km across. Mainly quartz-rich lithic wackes and granule conglomerates interbedded with siltstone amd mudstone.
Definition of Lower Boundary: The Robinson Member is locally conformable with the underlying Goat Gills Member (breccia) [NY 1895 1624], but the lowest beds are highly disturbed and in Goats Gills [NY 1914 1630] they are truncated against the underlying unit.
Definition of Upper Boundary: The Robinson Member is surrounded by an envelope of sandstone-rich Buttermere Formation rocks.
Thickness: 250m
Geographical Limits: Occurs in the south of the Skiddaw inlier within the Buttermere Formation and bounded to the north by the Causey Pike Fault.
Parent Unit: Buttermere Formation (BUF)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Robinson, east of Buttermere. Cooper et al, 1995 
Type Area  In Littledale, the maximum thickness is exposed but the base is not seen. Cooper et al, 1995 
Reference(s):
Cooper, A H, Rushton, A W A, Molyneux, S G, Hughes, R A, Moore, R M and Webb, B C. 1995. The stratigraphy,correlation, provenance and palaeogeography of the Skiddaw Group (Ordovician) in the English Lake District. Geological Magazine, Vol.132(2), 185-211. 
Webb, B C and Cooper, A H. 1988. Slump folds and gravity slide structures in a Lower Palaeozoic marginal basin sequence (the Skiddaw Group), NW England. Journal of Structural Geology, Vol.10(5), 463-472. 
Webb, B C. 1990. The Buttermere Formation (Skiddaw Group) in the Robinson area. 74-82 in Moseley, F (Ed.), The Geology of the Lake District. [The Geologists' Association.] 
Cooper, D C, Lee, M K, Forty, N J, Cooper, A H, Rundle, C C, Webb, B C and Allen, P M. 1988. The Crummock Water Aureole: a zone of metasomatism and source of ore metals in the English Lake District. Journal of the Geological Society, Vol.145(4), 523-540. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E029