| Computer Code: |
TIL |
Preferred Map Code: |
TL |
| Status Code: |
Full |
| Age range: |
Brigantian Substage (CX)
— Brigantian Substage (CX) |
| Lithological Description: |
Buff to pale grey, fine- to medium-grained massive to thinly bedded dolostone and limestones, with shaly mudstone interbeds, common palaeosols and karstic surfaces with green clayey drapes, and bioclastic grainstones and calcaeous mudstones where undolomitised. Some sandy dolostones and dolomitic sandstones are present at the base of the formation. |
| Definition of Lower Boundary: |
The lower unconformable boundary is taken at the base of the lowest palaeosol, recognised by 1- 2 m of heterogeneous, friable siltstone and sandstone with carbonate nodules, above fine- to coarse-grained dolostones containing shaly mudstone partings, of the Cloud Hill Dolostone Formation. |
| Definition of Upper Boundary: |
The highest bed of limestone or dolostone in the Peak Limestone Group, is overlain rapidly by grey mudstone, siltstone or sandstone of the Millstone Grit Group or red-bed Permo-Triassic breccia of the Moira Formation. |
| Thickness: |
Estimated to be 60 m thick in the type area, and possibly up to 90 m between the Worthington Borehole and Cloud Hill Quarry. |
| Geographical Limits: |
South Derbyshire to north-west Leicestershire, between Ticknall [SK 35 24] and Thringstone, near Grace Dieu [SK 42 17]. |
| Parent Unit: |
Peak Limestone Group (PKLM)
|
| Previous Name(s): |
Carboniferous Limestone (Series) [Obsolete Name and Code: Use TIL]
(-1232)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Reference Section |
Base: South-west corner of Cloud Hill Quarry, about 14 m thick at the topmost part of the face. |
| Reference Section |
BGS Worthington Borehole (SK42SW/204), which displays a continuous cored sequence through the upper of 43 m of the formation (base not seen). |
| Type Area |
Top: Disused limestone quarries at Ticknall, south Derbyshire. |
| Reference Section |
BGS Ticknall Borehole (SK32SE/103), displaying 55 m of continous cored sequence from a probable unconformity at the base, to just below the top of the formation. |
| Reference(s): |
| Monteleone, P H, 1973. The Carboniferous Limestone of Leicestershire and south Derbyshire. Unpublished PhD thesis, University of Leicester. |
| Ambrose, K, and Carney, J N. 1997. Geology of the Ticknall area. British Geological Survey Technical Report WA/97/17. |
| Carney, J N, Ambrose, K and Brandon, A. 2001. Geology of the country between Burton, Loughborough and Derby. Description of 1:50k Sheet 141 (England and Wales). |
| Parsons, L M. 1918. The Carboniferous Limestone bordering the Leicestershire Coalfield. Quarterly Journal of the Geological Society, 73, 84-110. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E141
|
