The BGS Lexicon of Named Rock Units — Result Details

Craighall Conglomerate Formation

Computer Code: CHCG Preferred Map Code: CHCG
Status Code: Full
Age range: Early Devonian Epoch (DL) — Early Devonian Epoch (DL)
Lithological Description: A generally massive, well-rounded pebble and boulder (up to 0.6m diameter) conglomerate, of andesitic lava, locally quartzite and other lithologies of 'Highland' origin, interbedded with andesite, basaltic andesite and basalt lava members, together with minor sandstone, siltstone and mudstone beds.
Definition of Lower Boundary: An unconformable contact on ignimbrites of the Crawton Volcanic Formation or on Dalradian Supergroup metamorphic rocks, varied along the Highland Border area.
Definition of Upper Boundary: The base of the Scone Sandstone Formation, which is locally overlain by the Hatton Conglomerate Member, with the Highland conglomerate overlying the volcanic conglomerate.
Thickness: Over 500 m thick.
Geographical Limits: The north-western limit of the Strathmore Syncline in the Highland Border area, north-east of Perth in the Midland Valley of Scotland. sheets 48W, 56W, in the Blairgowrie area.
Parent Unit: Arbuthnott-Garvock Group (ATGK)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Basal contact seen in the River Ericht, section at Milton of Drimmie, upstream of Samuel's Pool [NO 1750 4765], continuing west of Craighall House [NO 172 469]. 
Reference(s):
Armstrong, M, Paterson, I B and Browne, M A E, 1985. Geology of the Perth and Dundee district. Memoir of the British Geological Survey, Sheets 48W, 48E and 49 (Scotland). 108pp. 
Fletcher, T P, 1993. Geology of the Blairgowrie-Rattray district. British Geological Survey Technical Report WA/93/97. 
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:
S056 S056 S048 S056 S047