The BGS Lexicon of Named Rock Units — Result Details

Mam Tor Beds

Computer Code: MT Preferred Map Code: MT
Status Code: Index Level
Age range: Kinderscoutian Substage (CK) — Kinderscoutian Substage (CK)
Lithological Description: Thinly to medium-bedded, upward-fining turbiditic cycles of grey-brown, very fine-to fine-grained, massive and laminated, micaceous sandstone overlain by grey, laminated siltstone and dark grey mudstone; bases of sandstones show a variety of sole marks and some trace fossils
Definition of Lower Boundary: A sharp upward change in a conformable succession from predominatly grey mudstone to sandstone. The base of the first sandstone bed above the Reticuloceras reticulatum Marine Band.
Definition of Upper Boundary: A sharp upward change in a conformable succession from sandstone to predominantly mudstone. The top of the last fine-grained sandstone bed immediately below the first massive, coarse-grained sandstone of the overlying Shale Grit.
Thickness: Up to 135 m thick.
Geographical Limits: Mam Tor, Hope Valley, upper Derwent Valley and Woolands Valley.
Parent Unit: Hebden Formation (HEBD)
Previous Name(s): none recorded or not applicable
Alternative Name(s): Mam Tor Sandstones
Stratotypes:
Type Section  Backscar of Mam Tor Landslip, west of Castleton, Derbyshire. Stevenson and Gaunt, 1971; Allen, 1960 
Reference(s):
Allen, J R L. 1960. The Mam Tor Sandstones: a "turbiditic" facies of the Namurian deltas of Derbyshire, England. Journal of Sedimentary Petrography, Vol 30, 193-208. 
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