The BGS Lexicon of Named Rock Units — Result Details

Monsal Dale Limestone Formation

Computer Code: MO Preferred Map Code: Mo
Status Code: Full
Age range: Brigantian Substage (CX) — Brigantian Substage (CX)
Lithological Description: Pale to medium grey, thickly-bedded and bioturbated well-sorted biosparites and pelsparites, to poorly sorted biomicrites. The limestone contains sporadic chert nodules, and emergent surfaces are marked by pedogenic tubes and crusts of brown laminated micrite. The lower part at Cressbrook Dale - Millers Dale and all around Litton, comprise dark grey thinly-bedded, cherty limestone containing dark argillaceous partings, the limestone being typically a poorly sorted bioclastic calcisiltite with a micritic matrix, and includes several volcanic members of basaltic lava and tuff.
Definition of Lower Boundary: A sharp unconformable boundary with the lowest bed of dark limestone, commonly marked by abundant Girvanella or Saccamminopsis, above the pale grey limestones of the Bee Low Limestone Formation. Elsewhere, the boundary is marked by the base of the Upper Millers Dale Lava, Winstermoor Lava or Lower Matlock Lava.
Definition of Upper Boundary: Taken at the base of the dark grey - grey-brown limestones of the overlying Eyam Limestone, which locally overlies an erosive surface and clay wayboard above the pale to medium grey limestone, of the Monsal Dale Limestone Formation.
Thickness: Appears 143 m thick in the Cressbrook Dale section (200m at Ashford on the Water [SK 19 69], and 359 m at Longstone Edge [SK 20 73].
Geographical Limits: Northern and eastern parts of the Peak District.
Parent Unit: Peak Limestone Group (PKLM)
Previous Name(s): Lower Monsal Dale Beds [Obsolete Name And Code: See MO] (LMD)
Monsal Dale Formation (-3555)
Matlock Group [Obsolete Name And Code: Use MO] (MAG)
Upper Monsal Dale Beds [Obsolete Name And Code: See MO] (UMD)
Monsal Dale Group (-401)
Monsal Dale Limestones (-402)
Monsal Dale Limestones Formation (-403)
Monsal Dale Beds (-1068)
Alternative Name(s): none recorded or not applicable
Reference Section  Railway cutting betwenn Cressbrook and Litton tunnels. The base of the formation rests upon an erosion surface with palaeokarstic solution hollows on top of the Bee Low Limestone Formation. 
Type Section  Cressbrook Dale: Composite section of full 143 m thickness of formation. Stevenson and Gaunt, 1971. 
Reference Section  Station Quarry, Miller's Dale: exposes the basal 12.4 m, and the boundary with the underlying Bee Low Limestones Formation. 
Type Section  Furness Quarry: shows the uppermost 56.92 m of the formation and the boundary with the overlying Eyam Limestone Formation. 
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. 
Aitkenhead, N and Chisholm, J I. 1982. A standard nomenclature for the Dinantian formations of the Peak District of Derbshire and Staffordshire. Report of the Institute of Geological Sciences, No.82/8. 
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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E099 E111