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== Border Group [http://www.bgs.ac.uk/lexicon/lexicon.cfm?pub=BDR (BDR)], Carboniferous, Northern England Province==

===Lithology===
The Border Group (Lumsden et al. 1967<ref>Lumsden, G I, Tulloch, W, Howells, M F, and Davies, A. 1967. The geology of the neighbourhood of Langholm.''Memoir of the Geological Survey of Great Britain'', Sheet 11 (Scotland).</ref>; Day, 1970<ref name="day70"> Day, J B W. 1970. Geology of the country around Bewcastle.''Memoir of the Geological Survey of Great Britain'', Sheet 12 (England and Wales).</ref>) consists of two sedimentary formations corresponding to some extent to the geographically extended, former Lower and Middle Border groups of Day (1970<ref name="day70" />; see also Waters et al., 2007<ref>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.</ref>). The lower, the [[Lyne Formation]] (which equates with the ‘Cementstones’ of older terminology in Northumberland) comprises strata of ''heterolithic'' ''clastic'' and ''nonmarine carbonate facies''. The [[Fell Sandstone Formation]], of ''fluviodeltaic (‘Millstone Grit’) facies'', diachronously overlies the [[Lyne Formation]]. Thin olivine basalt lavas occur as the Kershopefoot basalts (Williamson in Stephenson et al., 2003)<ref>Stephenson, D, Loughlin, S C, Millward, D, Waters, C N, and Williamson, I T.2003.Carboniferous and Permian Igneous Rocks of Great Britain North of the Variscan Front.''Geological Conservation Review Series'', No. 27. (Peterborough: Joint Nature Conservation Committee.)</ref>.

===Lower and upper boundaries===
The base of the group is conformable where the interbedded sandstones, limestones, anhydrites, rootlet beds and thin coals of the [[Ballagan Formation]] ([[Inverclyde Group]]) pass upward into the cyclical sequences of sandstone, mudstone and thin limestone of the [[Lyne Formation]]. This is the presumption at Bewcastle and Kirkbean, and it has been proved in a borehole at Annandale. The base is also conformable at Brampton where the [[Ballagan Formation]] passes upwards into the sandstone-dominated [[Fell Sandstone Formation]]. However, in the north-east part of the Northumberland Trough the same boundary is unconformable; and within the central part of the trough, the base of the group has not been proved. The base of the [[Yoredale Group]] ''(mixed shelf carbonate and deltaic (‘Yoredale’) facies)'' defines the top of the Border Group.

===Thickness===
Greater than 1350 m thick in the central part of the Northumberland Trough.

===Distribution===
The Border Group is restricted in geographical extent to the Northumberland Trough and Solway Basin.

===Age===
It is late Tournaisian to Holkerian in age.

== References ==
<references/>
[[Category:Carboniferous lithostratigraphical nomenclature]]

Border Group - Revision history

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Geosource>Volunteer 01 at 11:46, 14 July 2015