| Computer Code: |
ATG |
Preferred Map Code: |
ABT |
| Status Code: |
Full |
| Age range: |
Lochkovian Age (DO)
— Pragian Age (DP) |
| Lithological Description: |
[Obsolete: use ATGK] Sandstone predominates, interbedded with clast-supported conglomerate with well-rounded boulders, cobbles and pebbles predominantly of lava, psammite and quartzite in the north-east and adjacent to the Highland Boundary Fault. Siltstone and mudstone are interbedded with the sandstone, particularly in Dundee area. Piles of andesitic, basaltic and rhyolitic lavas, locally very thick, are interbedded with conglomerate and sandstone in many areas. Lenses and thicker formations of volcaniclastic sandstone are interbedded with conglomerate in the Stonehaven area and are associated with lavas elsewhere. |
| Definition of Lower Boundary: |
Diachronous, rising to higher levels towards the south-west. In the type area it lies at top of highest lava of Crawton Volcanic Formation, where this is overlain by clast-supported conglomerate. Elsewhere its base is taken to lie at the eroded top of the Lintrathen Porphyry or its presumed correlatives (cf. Paterson and Harris, 1969). Where these horizons are absent, on sheets 66E and 67, the base has been taken at the base of the lowest of the series of andesitic lavas that characterise the Arbuthnott Group in that area. |
| Definition of Upper Boundary: |
Diachronous, taken to lie at top of thick pile of andesitic lavas in south-west (Ochil Volcanic Formation) and north-east (Montrose Volcanic Formation) of crop. In Dundee area, taken at level of top of highest fine-grained horizon (`fish-bed') at the top of the Dundee Formation. |
| Thickness: |
Variable; the complete group ranges in thickness from 880-1350m in the Stonehaven area, while in the Stirling area, the Ochil Volcanic Formation alone reaches a maximum of 2400m. |
| Geographical Limits: |
North Midland Valley, Arran to Stonehaven. |
| Parent Unit: |
none recorded or not applicable
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Partial Type Section |
Sea cliffs and foreshore, Crawton Bay to Whistleberry. |
| Type Area |
Dundee area. [see also type sections of constituent formations.] |
| 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. |
| Carroll, S, 1995. Geology of the Auchenblae District. British Geological Survey Technical Report. WA/95/80. |
| Carroll, S, 1995. Geology of the Laurencekirk District. British Geological Survey Technical Report No.WA/95/81. |
| Carroll, S, 1994. Geology of the Stonehaven District. 1:10 000 Sheets NO88NW, NO88NE, NO88SW and NO88SE. British Geological Survey Technical Report WA/94/19. |
| 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 |
| Campbell, R, 1913. The geology of south-eastern Kincardineshire. Transactions of the Royal Society of Edinburgh, Vol.48, pp.923-960. |
| Carroll, S. 1994. Geology of the Inverbervie and Catterline district, 1:10 000 sheets NO87NW, NO87NE and NO87SW. British Geological Survey, Technical Report, WA/94/20. |
| Richardson, J B, Ford, J H and Parker, F, 1984. Miospores correlation and age of some Scottish Lower Old Red Sandstone sediments from the Strathmore region (Fife and Angus). Journal of Micropalaeontology, Vol.3, 109-124. |
| Francis, E H, Forsyth, I H, Read, W A and Armstrong, M. 1970. The geology of the Stirling district. Memoir of the Geological Survey of Great Britain, Sheet 39 (Scotland). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
S067
S066
S013
S338
S038
S045
|
