The BGS Lexicon of Named Rock Units — Result Details

Inchmurrin Conglomerate Member

Computer Code: IMC Preferred Map Code: IMC
Status Code: Full
Age range: Early Devonian Epoch (DL) — Early Devonian Epoch (DL)
Lithological Description: A conglomerate with clast sizes mostly from 10 to 15 cm, predominantly of quartzite in the lower part but with igneous and volcanic clasts also, at higher levels.
Definition of Lower Boundary: The Inchmurrin Conglomerate Member is commonly faulted against Dalradian or Highland Border Complex rocks. Mapping in the Gualann area suggests that the Inchmurrin Conglomerate Member lies within the Ruchill Flagstone Formation, overlying the Craig of Monievreckie Conglomerate Formation.
Definition of Upper Boundary: Originally, the top of the Inchmurrin Conglomerate Member was found to be unexposed or obscured by faulting (Paterson, Hall and Stephenson, 1992, p.7). Later mapping in the Balmaha-Gualann area (1995 season), suggests that the Inchmurrin Conglomerate Member is a conglomerate body within the Ruchill Flagstone Formation. Where not affected by faulting, it is overlain by a flaggy, locally pebbly sandstone of the Ruchill Flagstone Formation.
Thickness: At least 300 m thick.
Geographical Limits: Cardross-Drymen area, the north-west limb of the Strathmore Syncline, Sheets 30W, 38W, 38E.
Parent Unit: Ruchill Flagstone Formation (RLF)
Previous Name(s): Inchmurrin Conglomerate Formation (-2864)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Sheet SO30W. 
Reference(s):
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). 
Browne, M A E, Smith, R A and Aitken, A M. 2001. A lithostratigraphical framework for the Devonian (Old Red Sandstone) rocks of Scotland south of a line from Fort William to Aberdeen. Version 3. British Geological Survey Research Report RR/01/04. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S030 S038 S038