The BGS Lexicon of Named Rock Units — Result Details

Border Group

Computer Code: BDR Preferred Map Code: BDR
Status Code: Full
Age range: Chadian Substage (CI) — Holkerian Substage (CQ)
Lithological Description: The Border Group comprises interbedded sandstones, siltstones and limestones, with conglomerate and ferroan dolostone ("cementstone"). Component formations include the Lyne Formation , which comprises siltstone and dolostone with fine-grained sandstone, and the Fell Sandstone Formation, which comprises medium- to coarse-grained sandstone with siltstone and subsidiary fine-grained conglomerate and dolostone. Some members of the Lyne Formation are notable for their algal beds (eg the Main Algal Member). The Kershopefoot Basalt Beds are thin olivine-basalt flows within the Fell Sandstone Formation.
Definition of Lower Boundary: The thickest development is at Bewcastle where base of the unit is not seen. Here it comprises the Lyne Formation (formerly Lower Border Group) and the Fell Sandstone Formation (formerly Middle Border Group). In Annerdale, the Lyne Formation is conformable on interbedded siltstones, sandstones and ferroan dolostones ("cementstones") of the the Kirkbean Member of the Ballagan Formation (Inverclyde Group), as seen in the Hoddon No.2 Borehole (NY17SE/3, NY1641 7285). At Kirkbean, the Lyne Formation is presumed to rest unconformably on the Ballagan Formation, and comprises siltstone and dolomitic limestone with fine-grained sandstone, contrasting with the predominantly thin dolomitic limestone and fine-grained sandstone Ballagan Formation sequence. At Brampton, the base of the unit is taken at the base of interbedded thick sandstones with thin limestones and mudstones of the Fell Sandstone Formation, which rests conformably on the Ballagan Formation. Southwest of Berwick-upon-Tweed, the Fell Sandstone Formation is characterized by the presence of seven thick sandstones separated by laterally persistent mudstones. The base is taken at the base of the lowest sandstone (Thornton Sandstone of Turner et al., 1993), which rests conformably on the "cementsones facoies" (siltstones,sandstones and ferroan dolostones) of the Ballagan Formation.
Definition of Upper Boundary: In Annandale, thick medium- to coarse-grained sandstones, siltstones and seatrocks of the Fell Sandstone Formation of the Border Group are overlain conformably by interbedded sandstone, siltstone and limestone the Tyne Limestone Formation (Yoredale Group). Locally in the Annandale and Langholm districts the base of the Tyne Limestone Formation is represented by interbedded tuffaceous sandstones and siltstones of the Glencartholm Volcanic Beds. In Bewcastle the base of the Tyne Limestone Formationis represented by marine fossiliferous limestone and mudstone of the Clattering Band. In the Clattering Band colonial corals, including Lithostrtion martini and L. portlocki and gigantoproductids (Semiplanus sp.) become common. The upper boundary of the Border Group is diachronous across the Northumberland and Solway basins.
Thickness: More than 1350m
Geographical Limits: Northumberland and Solway basins, including the Solway Firth, Annandale, Langholm, Kelso district and Berwickshire from the Solway Coast (280000 548000) to the Berwickshire Coast at Berwick-upon-Tweed (400000 650000).
Parent Unit: Not Applicable (-)
Previous Name(s): Previously Comprised Lower, Middle And Upper Border Groups (-1974)
Alternative Name(s): none recorded or not applicable
Type Area  No stratotypes defined in original description in Langholm memoir. Refer to stratotypes of the Lyne Formation (Bewcastle) (LYNE) and the Fell Sandstone Formation (FELL). 
Nairn, A E M. 1956. The lower Carboniferous rocks between the rivers Esk and Annan Dumfriesshire. Transactions of the Geological Society of Glasgow, 22, p.80-93. 
Frost, D V and Holliday, D W. 1980. Geology of the country around Bellingham. Memoir of the British Geological Survey, Sheet 13 (England & Wales). 
Craig, G Y. 1956. The Lower Carboniferous outlier of Kirkbean, Kirkcudbrightshire. Transactions of the Geological Society of Glasgow, Vol. 22, 113 - 132. 
Leeder, M R. 1974. Lower Border Group (Tournaisian) fluvio-deltaic sedimentation and palaeogeography of the Northumberland Basin. Proceedings of the Yorkshire Geological Society, Vol.40, 129 - 180. 
Smith, R and McMillan, A A. 1996. Mineral investigations in the Northumberland Trough: part 3, Ecclefechan - Waterbeck area. BGS Mineral Recconnaisance Programme Open File Report No. 21. 
Turner, B R, Younger, P L and Fordham, C E. 1993. Fell Sandstone Group lithostratigraphy south-west of Berwick-upon-Tweed: implications for the regional development of the Fell Sandstone. Proceedings of the Yorkshire Geological Society. Vol.49, Part 4, 269-281. 
George, T N, Johnson, G A L, Mitchell, M, Prentice, J E, Ramsbottam, W H C, Sevastopulo, G D and Wilson, R B. 1976. A correlation of the Dinantian rocks of the British Isles. Special Report of the Geological Society of London, No 7. 
Lumsden G I, Tulloch W, Howells M F and Davies A. 1967. The geology of the neighbourhood of Langholm. Memoir of the Geological Survey, Sheet 11 (Scotland). 
Day, J B W and others, 1970. Geology of the neighbourhood around Bewcastle. Memoir of the British Geological Survey, Sheet 12. (England and Wales). 
Lintern, B C and Floyd, J D. 2000. Geology of the Kirkcudbright-Dalbeattie District. Memoir of the British Geological Survey, Sheets 5W, 5E and part of 6W (Scotland). 
Smith, S A and Holliday, D W. 1991. The sedimentology of the Middle and Upper Border groups (Visean) of the Stonehaugh Borehole, Northumberland. Proceedings of the Yorkshire Geological Society, Vol.48, 435-446. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S011 E012 E020 E023 S017 S006 S017 S034 E005 E001 E002 E013