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)
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Previous Name(s): |
none recorded or not applicable
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Partial Type Section |
The banks of Bervie Water, Deep to Corbies Pot, showing the relationship with the Tannadice Sandstone Member. |
Partial Type Section |
Banks of Bervie Water. |
Partial Type Section |
Corbies Den. |
Reference(s): |
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 |
Carroll, S, 1995. Geology of the Auchenblae District. British Geological Survey Technical Report. WA/95/80. |
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. |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
S067
S066
E057
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