The BGS Lexicon of Named Rock Units — Result Details

Glendearg Formation

Computer Code: GDE Preferred Map Code: GDE
Status Code: Full
Age range: Llandovery Epoch (SL) — Llandovery Epoch (SL)
Lithological Description: Sandstone, typically fine- to medium-grained but ranging from very fine- to coarse-grained. Generally medium- to thick-bedded over thicknesses of tens of metres interspersed with units up to few metres very thin to thin-bedded. Scattered very thick beds in some cases parallel laminated throughout. Interbedded siltstone or silty mudstone generally in thin beds. Sandstone and siltstone typically greenish grey when fresh, pale brown weathering. Distinguished from the Selcoth Formation by the occurrence of very thick beds of parallel laminated sandstone. Other distinguishing factors include the wider age range (although overlapping in lowersmost part) and no evidence of a basal stratigraphical relationship with the Moffat Shale Group. Distinguished from Eskdalemuir Formation by the occurrence of very thick beds of parallel laminated sandstone and paler, less pervasive weathering reflecting lower carbonate content of the sandstone.
Definition of Lower Boundary: Faulted; no stratigraphical contact preserved.
Definition of Upper Boundary: Faulted; no stratigraphical contact preserved.
Thickness: Uncertain, may be few hundred metres to 2000m
Geographical Limits: Southern Scotland.
Parent Unit: Ettrick Group (ETRK)
Previous Name(s): Hawick Rocks (-3383)
Queesnberry Formation (-3420)
Hawick Group (HWK)
Queensberry Grits (-1552)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Scabcleugh Burn and Craig Hill, Eskdale. 
Partial Type Section  Glendearg Burn, north of Eskdalemuir. Webb et al, 1993; White et al, 1991. 
Reference(s):
British Geological Survey. 1991. Moffatdale. Solid Geology. 1:25 000. Classical areas of British geology. (Keyworth, Nottingham: British Geological Survey). 
Peach, B N and Horne, J. 1899. The Silurian Rocks of Britain, Volume 1. Scotland. Memoir of the Geological Survey of the United Kingdom. 
White, D E, Barron, H F, Barnes, R P and Lintern, B C. 1991. Biostratigraphy of late Llandovery (Telychian) and Wenlock turbiditic sequences in the SW Southern Uplands, Scotland. Transactions of the Royal Society of Edinburgh: Earth Sciences, Vol.82, 297-322. 
Webb, B C, Rushton, A W A and White, D E. 1993. Moffatdale and the upper Ettrick valley. Description of the solid geology of parts of 1:25000 sheets NT10, 11, 20 and 21. Classical Areas of British Geology. (London: British Geological Survey, HMSO.) 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable