The BGS Lexicon of Named Rock Units — Result Details

Deep Conglomerate Formation

Computer Code: DECO Preferred Map Code: DECO
Status Code: Full
Age range: Lochkovian Age (DO) — Pragian Age (DP)
Lithological Description: A pebbly and cobbly, well-rounded, clast-supported conglomerate of lava, psammite, quartzite and feldspar-porphyry in a matrix of poorly-sorted, fine- to medium-grained lithic sandstone, commonly with lenses of trough cross-bedded pebbly sandstone.
Definition of Lower Boundary: The base of the formation is placed at the top of a thick succession of andesitic lavas of the Montrose Volcanic Formation where this is conformably and somewhat diachronously overlain by a massive clast-supported conglomerate, above which it passes laterally into, and interfingers with, sandstone of the Tannadice Sandstone Member of the Scone Sandstone Formation.
Definition of Upper Boundary: A clast-supported conglomerate conformably, somewhat diachronously and locally interfingered with the base of a red, massive or laminated, poorly-sorted siltstone of the Cromlix Mudstone Formation.
Thickness: Up to 880 m thick in the type area, passing laterally into sandstone of Tannadice Sandstone Member towards the south-west.
Geographical Limits: North-eastern Midland Valley, between Drumlithie and the River South Esk.
Parent Unit: Arbuthnott-Garvock Group (ATGK)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Banks of Bervie Water. 
Partial Type Section  Corbies Den. 
Partial Type Section  The banks of Bervie Water, Deep to Corbies Pot, showing the relationship with the Tannadice Sandstone Member. 
Reference(s):
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. 
Carroll, S, 1995. Geology of the Laurencekirk District. British Geological Survey Technical Report No.WA/95/81. 
Carroll, S, 1995. Geology of the Auchenblae District. British Geological Survey Technical Report. WA/95/80. 
Armstrong, M and Paterson, I B, 1970. The Lower Old Red Sandstone of the Strathmore Region. Report of the Institute of Geological Sciences No.70/12 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S067 S066 E057