The BGS Lexicon of Named Rock Units — Result Details

Eycott Volcanic Group

Computer Code: EVG Preferred Map Code: EVG
Status Code: Full
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: Medium-K continental-margin type basalt-andesite-rhyolite volcanic association, transtional between tholeiitic and calc-alkaline affinities. Comprises porphyritic basalt, basaltic andesite, andesite and dacite lava flows and sills with intercalated volcaniclastic deposits, comprising tuff, lapilli-tuff, breccia, conglomerate and volcaniclastic sedimentary rocks.
Definition of Lower Boundary: Taken at the base of volcanic rocks overlying mudstones of Skiddaw Group; in parts defined by base of Overwater Formation. Angular unconformity seen in some localities (Millward and Molyneux, 1992); elsewhere proved from biostratigraphical evidence from underlying Skiddaw Group.
Definition of Upper Boundary: Unconformity with overlying Carboniferous strata.
Thickness: To 3200m
Geographical Limits: Bothel-Binsey-Brae Fell-Caldbeck Fells; Eycott Hill; Greystoke Park (BGS 1:50k sheets 23, 24, 29); Melmerby Fell (Cross Fell Inlier) (BGS 1:50k sheet 24), Cumbria.
Parent Unit: Not Applicable (-)
Previous Name(s): Eycott Lava [Obsolete Name And Code: See EVG] (EYLA)
High Ireby Formation [Obsolete Name And Code: Undifferentiated Part Of EVG] (HIF)
Binsey Formation [Obsolete Name And Code: Undifferentiated Part Of EVG] (BY)
Eycott Group (-2177)
Undifferentiated Part Of Borrowdale Volcanic Group (-2178)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Fell side of Binsey 
Reference Section  Eycott Hill 
Reference(s):
Millward, D, 2003. A stratigraphical framework for the Lower Palaeozoic igneous rocks of the Lake District and adjacent areas. British Geological Survey Research Report, RR/03/?? 
Millward, D et al., 2000. The Eycott Volcanic Group, an Ordovician continental margin andesite suite in the English Lake District. Proceedings of the Yorkshire Geological Society, Vol.53, 81-96. 
Downie, C and Soper, N J, 1972. Age of the Eycott Volcanic Group and its conformable relationship to the Skiddaw Slates in the English Lake District. Geological Magazine, Vol.109, 259-268. 
Millward, D and Molyneaux, S G, 1992. Field and Biostratigraphic Evidence for an unconformity at the base of Eycott Volcanic Group in the Lake District. Geological Magazine, Vol.129/1, p.77-92. 
Wadge, A J, 1978.Classification and stratigraphical relationships of the Lower Ordovician Rocks. 68-78 in The Geology of the Lake District (editor F. Moseley). Yorkshire Geological Society, Occasional Publication No.3. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E023 E029 E024