The BGS Lexicon of Named Rock Units — Result Details

Miller's Dale Limestone Member

Computer Code: MDA Preferred Map Code: notEntered
Status Code: Full
Age range: Asbian Substage (CR) — Asbian Substage (CR)
Lithological Description: A massive, pale grey to grey, fine-grained calcarenite with common fossils, particularly corals, brachiopods and crinoid debris. Rare cherts occur locally in the middle part of the Member. Locally the limestones are pure white and/or have a more bedded character. Oolitic beds are present locally. The Dove Holes Tuff, 2.2m thick, occurs about 15m above the base of the Member and comprises pyritous greenish grey clay with limestone lapilli, resting on a palaeokarstic surface.
Definition of Lower Boundary: Limestone of the Miller's Dale Limestone Member overlies vesicular lava of the Lower Miller's Dale Lava Member. Locally, the basal part of the limestone is tuffaceous.
Definition of Upper Boundary: The pale grey, massive limestone of the member is separated from the generally darker limestones of the Monsal Dale Limestone Formation by a palaeokarstic surface. The Upper Miller's Dale Lava Member or a laterally equivalent bed of altered clay may intervene locally.
Thickness: Reaches 43m near Dove Holes (SK 08 77).
Geographical Limits: Only recognised as a separate unit where the underlying Lower Miller's Dale Lava Member is present, restricting the Miller's Dale Limestone Member to the Wye Valley area near Buxton, in the north of the Peak District Dinantian inlier.
Parent Unit: Bee Low Limestone Formation (BLL)
Previous Name(s): Miller's Dale Beds (-1686)
Miller's Dale Limestones Formation (-4185)
Miller's Dale Limestones (-2936)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Ashwood Dale section in a railway cutting shows the lower part of the member, including the Davidsonina septosa Bed. Aitkenhead et al., (1985) 
Reference(s):
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. 
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 W. 1933. The Lower Carboniferous succession in the Wye Valley region of North Derbyshire. Journal of the Manchester Geological Association, Vol.1, 125-145. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E099 E111