The BGS Lexicon of Named Rock Units — Result Details

Tay Catchments Subgroup

Computer Code: TAYCA Preferred Map Code: notEntered
Status Code: Full
Age range: Devensian Stage (QD) — Holocene Epoch (QH)
Lithological Description: Includes the fluvial and related organic deposits of the catchments surrounding the Tay Estuary. The deposits include alluvium and river terrace deposits comprising gravel, sand, silt, peat and head. Rock types are principally of Carboniferous and Devonian strata (sandstone, siltstone) with volcanic (basalt) and intrusive igneous rocks (microdiorite) of Midland Valley provenance. North of the Highland Boundary Fault the deposits are dominantly derived from Dalradian metasedimentary and Caledonian igneous rocks of the Grampian Highlands. South of the fault variable but generally minor components of Dalradian metasedimentary and Caledonian igneous rocks are present. A suite of fluvial (alluvium and river terrace deposits) and associated organic and lacustrine sediments that contain clasts derived from Palaeozoic rocks and glacigenic deposits cropping out in the catchment of the River Tay and other rivers flowing directly to the Firth of Tay, including the rivers Earn, Almond, Tummel, Isla, and the rivers North Esk and South Esk of Angus. Late Devensian to Holocene (MIS 2-1).
Definition of Lower Boundary: Unconformable contacts with units of the Midland Valley, Mearns and Central Grampian Glacigenic subgroups and bedrock.
Definition of Upper Boundary: Generally the ground surface, but units of the subgroup may be overlain locally by mass movement deposits or may locally interfinger with units of the British Coastal Deposits Group.
Thickness: Up to 25 m.
Geographical Limits: The present physical catchments of the River Tay and tributaries, the Firth of Tay and the Montrose Basin. The catchments extend across Perthshire and Angus (Strathmore).
Parent Unit: Britannia Catchments Group (BCAT)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
none recorded or not applicable
Reference(s):
McMillan, A A, Hamblin, R J O and Merritt, J W. 2005. An overview of the lithostratigraphical framework for the Quarternary and Neogene deposits of Great Britain (onshore). British Geological Survey Research Report RR/04/04. 
McMillan, A A, Hamblin, R J O, and Merritt, J W. 2011. A lithostratigraphical framework for onshore Quaternary and Neogene (Tertiary) superficial deposits of Great Britain and the Isle of Man. British Geological Survey Research Report, RR/10/03. 343pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable