The BGS Lexicon of Named Rock Units — Result Details

Upper Miller's Dale Lava Member

Computer Code: UMB Preferred Map Code: UMB
Status Code: Full
Age range: Brigantian Substage (CX) — Brigantian Substage (CX)
Lithological Description: An amygdaloidal olivine basalt with calcite and chlorite infilling vesicles. At the type locality the lava is brown-weathered with a flow banding and degraded lava blocks up to 0.6 m diameter. In Miller's Dale, where the member is thickest, the member was subdivided into a 5.2 m thick tuff with a thin amygdaloidal basalt, overlain by a 30 m thick lava, at least in part comprising non-vesicular, holocrystalline basalt with spheroidal weathering (Walters and Ineson, 1981).
Definition of Lower Boundary: At the type section, basalt of the Upper Miller's Dale Lava Member rests upon dark grey, thinly bedded, fine-grained limestone of the Miller's Dale Limestone Formation. Outside of the Miller's Dale area the Member rests disconformably upon pale grey limestones of the Bee Low Limestone Formation.
Definition of Upper Boundary: At the type locality, an irregular upper surface of the lava is overlain by grey, fine-grained, irregularly bedded limestones of the Monsal Dale Limestone Formation, including rounded and decomposed fragments of lava immediately above the boundary.
Thickness: Up to about 35 m thick in Miller's Dale (SK 140 730), decreasing markedly to the east toward the type locality.
Geographical Limits: Nearly continuous outcrop from Hurdlow Town (SK 112 669) and Miller's Dale (SK 134 731) and an isolated outcrop at Harpur Hill (SK 066 713) and Cressbrook Dale (SK 173 724).
Parent Unit: Monsal Dale Limestone Formation (MO)
Previous Name(s): Upper Millers Dale Basalt (-2518)
Upper Miller's Dale Lava (-3745)
Alternative Name(s): none recorded or not applicable
Type Section  Litton Mill disused railway cutting, where the member is 5.18 m thick. (Cope, 1937; Walkden, 1977; Waters, 2003). 
Reference Section  Two small quarries (SK 134 731 and 134 730) west of the disused Lime Works Quarry expose of 10 m of non-vesicular lava, part of the 35 m succession formerly exposed at the Lime Works Quarry. (Walters, 1981). 
Stevenson, I P and Gaunt, G D, 1971. Geology of the country around Chapel-en-le-Frith. Memoir of the Geological Survey of Great Britain, England and Wales, Sheet 99. 
Cope, F. 1937. Some Features In The D1-D2 Limestones Of The Miller's Dale Region, Derbyshire. Proceedings of the Yorkshire Geological Society, Vol. 23-42, 178-195. 
Walkden, G M. 1977. Volcanic and erosive events on an Upper Visean carbonate platform, North Derbyshire. Proceedings of the Yorkshire Geological Society, Vol. 41, 347-367. 
Aitkenhead, N, Chisholm, J I and Stevenson, I P. 1985. Geology of the country around Buxton, Leek and Bakewell. Memoir of the British Geological Survey, England and Wales Sheet 111. 
Waters, C N. 2003. Carboniferous and Permian igneous rocks of central England and the Welsh Borderland. In: Carboniferous and Permian Igneous Rocks of Great Britain North of the Variscan Front. (editors Stephenson D, Loughlin S C, Millward D, Waters C N, and Williamson I T.), pp. 279-316, Geological Conservation Review Series, No. 27 (JNCC). 
Walters, S G and Ineson, P R. 1981. A review of the distribution of and the correlation of igneous rocks in Derbyshire, England. Mercian Geologist, Vol. 8, 81-132. 
Stephenson, D, Loughlin, S C, Millward, D, Waters, C N and Williamson, I. 2003. Carboniferous and Permian igneous rocks of Great Britain, north of the Variscan Front. Geological Conservation Review Volume 27. Joint Nature Conservation Committee: Peterborough. 374 pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E111 E099