The BGS Lexicon of Named Rock Units — Result Details

Strathclyde Group

Computer Code: SYG Preferred Map Code: SYG
Status Code: Full
Age range: Chadian Substage (CI) — Brigantian Substage (CX)
Lithological Description: The ascending sequence of the Strathclyde Group (Paterson and Hall, 1986; see also Browne et al., 1999, fig. 2) includes: In the western Midland Valley of Scotland, the Birgidale, Laggan Cottage Mudstone, Clyde Plateau Volcanic, Kirkwood, and Lawmuir formations; In Fife, the Fife Ness, Anstruther, Pittenweem, Sandy Craig, and Pathhead formations; In West Lothian, the Arthur's Seat Volcanic, Gullane, and West Lothian Oil-Shale formations; In East Lothian, the Garleton Hills Volcanic, Gullane, and Aberlady formations. The group comprises mainly heterolithic clastic and nonmarine carbonate facies strata deposited in fluviatile, deltaic and lacustrine or lagoonal environments. Lithologies are laterally variable. The sedimentary rocks consist of interbedded sandstone, siltstone and mudstone (including oil shales) with common seatearth, coal and sideritic ironstone. The volcanic successions comprise typically transitional to mildly alkaline lavas, pyroclastic rocks and volcaniclastic sedimentary rocks. Thin bioclastic limestone occurs within the uppermost part of the group that is characterised by the incoming of Yoredale-type cyclothems representing increasing marine conditions (Francis, 1991). Visean (Chadian to Brigantian) in age.
Definition of Lower Boundary: The base of the group is taken, in Fife, at the conformable base of the Fife Ness Formation; in the Lothians, at the mainly conformable base of the Gullane Formation or Arthur's Seat Volcanic Formation; and in Central and Western parts of the Midland Valley, at the sharp, irregular, unconformable base of the Clyde Plateau Volcanic Formation. The group represents a lithological change from the cornstone- and cementstone-bearing strata of the Inverclyde Group to a seatrock and/or coal-bearing sequence in which volcanic rocks may be common.
Definition of Upper Boundary: The base of the Clackmannan Group (mixed shelf carbonate and deltaic ('Yoredale') facies of a variable succession) defines the top of the Strathclyde Group.
Thickness: The Strathclyde Group exceeds 1250 m in thickness. Paterson and Hall (1986) suggested it is about 1500 m thick in the type area. It may locally exceed 2000 m.
Geographical Limits: The type area of the Strathclyde Group is the Glasgow area of the Strathclyde Region (see Paterson and Hall, 1986). Reference sections include coastal sections in east Fife, and the group extends across the Midland Valley of Scotland to include Machrihanish, the Isle of Arran, the Cumbrae isles and Bute and Cowal. It also includes Whitecleuch (Leadhills, Southern Uplands).
Parent Unit: Not Applicable (-)
Previous Name(s): Lower Oil Shale Group [Obsolete Name and Code: Use SYG] (LRO)
Calciferous Sandstone Measures [Obsolete Name and Code: Use INV, SYG] (CSM)
Upper Oil Shale Group [Obsolete Name and Code: Use SYG] (URO)
Oil-Shale Group [Obsolete Name and Code: Use SYG] (-2468)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Coastal sections, east Fife: Pathhead Beds, Sandy Craig Beds, Pittenweem Beds, Anstruther Beds, Fife Ness Beds. 
Type Area  Glasgow area, Strathclyde, Scotland. (Ref Sections: See Type Sections of components: Clyde Plateau Volcanic, Kirkwood, Lawmuir, Gullane, Aberlady, West Lothian Oil-Shale, Arthur's Seat Volcanic and Garleton Hills Volcanic formations). 
Reference(s):
MacGregor, A G, 1960. Division of the Carboniferous on Geological Survey Scottish Maps. Bulletin of the Geological Survey of Great Britain, No.16, 127-130. 
Paterson, I B and Hall, I H S. 1986. Lithostratigraphy of the late Devonian and early Carboniferous rocks in the Midland Valley of Scotland. British Geological Survey Report, 18/3. 
Dean, M T, Browne, M A E, Waters, C N and Powell, J H. 2011. A lithostratigraphical framework for the Carboniferous successions of northern Great Britain (onshore). British Geological Survey Research Report, RR/10/007. 165pp. 
Waters, C N, Gillespie, M R, Smith, K, Auton, C A, Floyd, J D, Leslie, A G, Millward, D, Mitchell, W I, McMillan, A A, Stone, P, Barron, A J M, Dean, M T, Hopson, P M, Krabbendam, M, Browne, M A E, Stephenson, D, Akhurst, M C, and Barnes, R P. 2007. Stratigraphical Chart of the United Kingdom: Northern Britain. (British Geological Survey.) 
Browne, M A E, Dean, M T, Hall, I H S, McAdam, A D Monro, S K and Chisholm, J I. 1999. A lithostratigraphical framework for the Carboniferous rocks in the Midland Valley of Scotland. British Geological Survey Research Report, RR/99/07. 
Waters, C N, Browne, M A E, Dean, M T and Powell, J H. 2007. Lithostratigraphical framework for Carboniferous successions of Great Britain (Onshore). British Geological Survey Research Report, RR/07/01. 
Francis, E H. 1991. Carboniferous. 347-392 in Geology of Scotland (3rd edition). Craig, G Y (editor). (London: The Geological Society.) 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S008 S015 S025 S024 S023 S024 S033 S021 S049 S030 S030 S039 S040 S041