The BGS Lexicon of Named Rock Units — Result Details

Deerness Volcanic Member

Computer Code: DSV Preferred Map Code: DsV
Status Code: Full
Age range: Givetian Age (DV) — Givetian Age (DV)
Lithological Description: (a) Basic lava (b) Tuff and tuffaceous sandstone (c) Agglomerate extrusions associated with sills of olivine-dolerite and teschenite locally, which can be distinguished only at coastal exposure. NOTE: The recognised lithologies crop out extensively on the Deerness Peninsula, Orkney. Poor exposure makes subdivision impractical inland, though intrusive and extrusive rock types have been recognised at some sites. Where intrusive basic rocks are recognised they are excluded from the Member. The name is changed from Eday Lavas because some of the rocks are sills, the Eday Flagstone, Eday Sandstone, etc. already exist, and the volcanic rocks do not occur on Eday, which is the type site for the remainder of the Eday sequence.
Definition of Lower Boundary: (a) Conformable contact on Eday Flagstone, (b) Conformable contact on Eday Flagstone, (c) Conformable and cross cutting contacts within lavas.
Definition of Upper Boundary: (a) Conformably overlain by tuffaceous sandstone within Eday Flagstone, (b) Conformably overlain by Eday Flagstone, (c) Conformable with Eday Flags and conformable/cross-cutting within lavas.
Thickness: (a) 2 flows: one >7m, second thin (0.5m) (b) 5m at Muckle Castle type section (c) unknown-thin.
Geographical Limits: Deerness, Tankerness, Copinsay and Shapinsay: Orkney Islands.
Parent Unit: Eday Flagstone Formation (EDF)
Previous Name(s): Eday Lavas [Obsolete Name And Code: Use DSV] (EDL)
Alkaline Basic Igneous Rocks In The Orkneys (-4009)
Eday Volcanic Rocks (-2769)
Eday Volcanics (-219)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Shore exposures between Haco's Ness and Scarf Skerry, extreme south-east of Shapinsay. 
Partial Type Section  Shore exposures at Point of Ayre, Deerness, Orkney. 
Partial Type Section  Shore exposures at Muckle Castle Stack, Deerness, Orkney. 
Reference(s):
Mykura W, 1976 British Regional Geology: Orkney and Shetland (HMSO, Edinburgh).] 
Astin, T R, 1985. The palaeogeography of the Middle Devonian Lower Eday Sandstone, Orkney. Scottish Journal of Geology, Vol.21, (3), p.353-375. 
Wilson, G V and others. 1935. The Geology of the Orkneys. Memoir of the Geological Survey of Scotland. 
Kellock, E, 1969. Alkaline basic igneous rocks in the Orkneys. Scottish Journal of Geology, Vol.5, (2), P.140-153. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S119 S120