| Computer Code: |
MTL |
Preferred Map Code: |
MtL |
| Status Code: |
Full |
| Age range: |
Tournaisian Age (CT)
— Chadian Substage (CI) |
| Lithological Description: |
Mainly carbonate mudstones, but with significant grainstones, locally cross-bedded, and oolites in upper part; ranges from peritidal to marine. Extensively dolomitized. |
| Definition of Lower Boundary: |
Not exposed. Taken where limestone becomes dominant over shale (Rose and Dunham, 1977, p.28). In practice, taken in boreholes at first significant shale parting, beds below there being assigned to `Basement Beds', now renamed `Low Furness Basal Formation'. |
| Definition of Upper Boundary: |
Base of "Red Hill Oolite", now redefined as the Red Hill Limestone Formation. |
| Thickness: |
0-135m |
| Geographical Limits: |
South Cumbria, West Cumbria. |
| Parent Unit: |
Great Scar Limestone Group (GSCL)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Martin Quarry (now partly filled in) (see Leviston, 1979 for section), near Dalton in Furness. |
| Reference Section |
Meathop Quarry, Grange-over-Sands (see Leviston, 1979 for section). |
| Reference(s): |
| Johnson, E W, Soper, N J, Burgess, I C, Ball, D F, Beddoe-Stephens, B, Carruthers, R M, Fortey, N J, Hirons, S, Merritt, J W, Millward, D, Roberts, B, Walker, A B and Young, B. 2001. Geology of the country around Ulverston. Memoir of the British Geological Survey, England and Wales, Sheet 48. |
| Dunham, K C and Rose, W C C. 1941. Geology of the iron-ore field of south Cumberland and Furness. Geological Survey of Great Britain, Wartime Pamphlet, No.16. |
| Leviston, D. 1979. A study of four localities, the Martin Limestone (Lower Carboniferous, Dinantian) of Furness and Grange-over-Sands. Proceedings of the Cumberland Geological Society, Vol.4, 3-20. |
| Nicholas, C. 1968. The stratigraphy and sedimentary petrology of the Lower Carboniferous rocks south west of the Lake District. Unpublished Ph.D. thesis, University of London. |
| Rose, W C C. 1977. Geology and Hematite deposits of South Cumbria. Economic Memoir for 1:50,000 Sheet 58 and southern part of Sheet 48. Memoir of the geological Survey of Great Britain. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E048
E039
|
