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
Type Area  In Littledale, the maximum thickness is exposed but the base is not seen. Cooper et al, 1995 
Type Area  Robinson, east of Buttermere. Cooper et al, 1995 
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. 
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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used: