The BGS Lexicon of Named Rock Units — Result Details
Cromlix Mudstone Formation
Computer Code: | CXF | Preferred Map Code: | CLX |
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Status Code: | Full | ||
Age range: | Emsian Age (DE) — Emsian Age (DE) | ||
Lithological Description: | Characteristically soft, bright red to dull brownish-red, maroon or purplish-brown, with green reduction spots in the north-eastern Midland Valley, generally massive but often thinly laminated, poorly-sorted, fine-grained silty sandstones, sandy siltstones, siltstones and mudstones, which lithologies may be locally interbedded with thin lenses of medium to coarse-grained pebbly sandstone. | ||
Definition of Lower Boundary: | Conformable, locally diachronous or interfingered base of red, massive or laminated and poorly-sorted, siltstone or mudstone, overlying fine- to medium-grained cross-bedded sandstone or conglomerate of the Arbuthnott-Garvock Group. | ||
Definition of Upper Boundary: | Conformable and gradational, generally diachronous, interfingering with and passing up into the Teith Sandstone Formation (or former Edzell Sandstone Formation) with increasing abundance of sandstone lithologies. | ||
Thickness: | From 240 m to 1200 m, passing laterally into the Teith Sandstone Formation (or former Edzell Sandstone Formation) towards the northwest. | ||
Geographical Limits: | Northern Midland Valley, between Stirling and Drumlithie. | ||
Parent Unit: | Strathmore Group (SEG) | ||
Previous Name(s): | Edzell Mudstone Formation [Obsolete Name And Code: See CXF]
(EDM)
Cromlix Formation [Obsolete Name and Code: Use CXF] (-2133) Laurencekirk Mudstone Formation [Obsolete Name And Code: See CXF] (LKMU) |
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Alternative Name(s): | Sannox Siltstones [Obsolete: use SXS] |
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Stratotypes: | |||
Reference Section | Exposure showing interfingering with former Edzell Sandstone Formation and Strathfinella Hill Conglomerate, banks of Shag Burn, Auchenblae, | ||
Partial Type Section | Banks of Bullie Burn, Braco. | ||
Reference Section | Banks of River Almond, Almondbank. | ||
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 Auchenblae District. British Geological Survey Technical Report. WA/95/80. | |||
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). | |||
Friend, P F, Harland, W B and Hudson, J D, 1963. The Old Red Sandstone and the Highland Boundary in Arran, Scotland. Transactions of the Edinburgh Geological Society, Vol.19, 363-425. | |||
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 | |||
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. | |||
1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
S066 S038 S048 S048 S056 S066 S030 S038 S039 S039 S047 |