The BGS Lexicon of Named Rock Units — Result Details

Gourock Sandstone Member

Computer Code: GKA Preferred Map Code: GKA
Status Code: Full
Age range: Tournaisian Stage (CT) — Tournaisian Stage (CT)
Lithological Description: White, cross-bedded sandstone with thin beds of red-brown silty mudstone; nodules and thin beds of pedogenic carbonate. This unit is distinguished from other units of the Clyde Sandstone Formation by the presence of thicker beds of sandstone, a lesser proportion of mudstone and less abundant calcareous nodules (Paterson and Hall, 1986; BGS, 1990). The sandstone is described as thick multi-storey bodies of white pebbly sandstone by Paterson et al. (1990).
Definition of Lower Boundary: Although the boundary is not exposed it has been mapped in the vicinity of Gourock Golf Course [NS 2230 7630] on the basis of the presence of thick beds of white, cross-bedded pebbly sandstone belonging to the Gourock Sandstone Member overlying the more thinly bedded rocks of the Knocknairshill Member.
Definition of Upper Boundary: Top not seen, but is presumed to be overlain by sandstone and mudstone strata of the Broadlee Glen Sandstone Member (Paterson and Hall, 1986) that include distinct plant debris and beds of grey mudstone (BGS, 1990).
Thickness: c.300m
Geographical Limits: Greenock district south of the River Clyde, also west of the Largs Fault Zone, Strathclyde, Scotland.
Parent Unit: Clyde Sandstone Formation (CYD)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Type Area  Currently best seen on 1:50K sheet S029E (Dunoon). 
British Geological Survey, 1990. Greenock. Scotland sheet 30W. 1:50 000 Series, Solid. (Keyworth, Nottingham: British Geological Survey.) 
Paterson, I B, Hall, I H S & Stephenson, D. 1990. Geology of the Greenock district: Memoir for 1:50000 geological sheet 30W and part of sheet 29E (Scotland). 
Paterson, I B and Hall, I H S, 1986. Lithostratigraphy of the late Devonian and early Carboniferous rocks in the Midland Valley of Scotland. British Geological Survey Report, 18/3. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S029 S030 S029