Computer Code: |
OLS |
Preferred Map Code: |
notEntered |
Status Code: |
Full |
Age range: |
Arnsbergian Substage (CG)
— Arnsbergian Substage (CG) |
Lithological Description: |
A pale to dark grey, fine-grained, argillaceous, crinoidal, bioclastic, locally shelly limestone. |
Definition of Lower Boundary: |
Generally seen as a change from a marine mudstone within the Upper Limestone Formation Orchard Beds. |
Definition of Upper Boundary: |
Generally seen as a change from limestone to thick marine mudstone within the Orchard Beds of the Upper Limestone Formation. |
Thickness: |
From 0.15m to 1.2m, or locally less, in the Airdrie, Falkirk and Glasgow districts, but reaches over 5m thickness in shelf settings in Ayrshire. |
Geographical Limits: |
Distributed throughout most of the outcrop and subcrop of the Upper Limestone Formation in the Midland Valley of Scotland, although it can be locally difficult to recognize in Fife, for example, in on-delta settings, where thick mudstones only of the Orchard Beds are present. |
Parent Unit: |
Upper Limestone Formation (ULGS)
|
Previous Name(s): |
none recorded or not applicable
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Reference Section |
Mossneuk Borehole, BGS reg. No. NS88NE/204, south of Alloa, with a unit base at 590m depth and a thickness of 0.23m. Orchard Farm is near Giffnock, Glasgow. |
Type Area |
Arden "basin". Hinxman et al., 1920. |
Reference(s): |
Cameron, I B, Aitken, A M, Browne, M A E and Stephenson, D. 1998. Geology of Falkirk District. Memoir of the British Geological Survey Sheet 31E (Scotland). |
Hall, I H S, Browne, M A E and Forsyth, I H. 1998. Geology of the Glasgow district. Memoir of the British Geological Survey, Sheet 30E (Scotland). |
Hinxman, L W, Anderson, E M and Carruthers, R G. 1920. The economic geology of the Central Coalfield of Scotland, Area IV; Paisley, Barrhead, Renfrew. Memoir of the Geological Survey, Scotland. |
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). |
Forsyth, I H, Hall, I H S and McMillan, A A. 1996. Geology of the Airdrie district. Memoir of the British Geological Survey, Sheet 31W (Scotland). |
Monro, S K. 1999. Geology of the Irvine District. Memoir of the British Geological Survey, Sheet 22W and part of 21E (Scotland). |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
S012
S023
S031
S031
S025
S024
S014
S015
S023
S032
S040
S040
S030
S039
S039
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