| Computer Code: |
DDDN |
Preferred Map Code: |
DDN |
| Status Code: |
Full |
| Age range: |
Sinemurian Age (JS)
— Sinemurian Age (JS) |
| Lithological Description: |
Sequence of grey mudstone beds with numerous ovoid, grey, ochreous-weathering, argillaceous limestone nodules 0.05 to 0.2 m in diameter, which are conspicuous in the soil. Some nodules are rich in small bivalves (Modiolus), and with gastropods. May include thin, silty, shelly, ferruginous limestone beds at base. Forms a strong feature with a dip slope in places. |
| Definition of Lower Boundary: |
Change up from bluish grey, shaly mudstone of undifferentiated Beckingham Member; at 40.56 m depth in type section Fulbeck Airfield Borehole F/B5 (SK95SW/17). |
| Definition of Upper Boundary: |
Change up into grey, shelly, bioclastic limestone of the undifferentiated Beckingham Member; at 38.62 in type section Fulbeck Airfield Borehole F/B5 (SK95SW/17). |
| Thickness: |
About 2 m; 1.94 m in type section. |
| Geographical Limits: |
East Midlands; north Leicestershire to Lincolnshire. Not recognised in north Lincolnshire, or south Leicestershire, where it passes south into either part of the more argillaceous Rugby Limestone Member of the Blue Lias Formation or part of the mudstone dominated Charmouth Mudstone Formation. |
| Parent Unit: |
Beckingham Member (BKHM)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Fulbeck Airfield Borehole F/B5 (SK95SW/17). |
| Reference(s): |
| Brandon, A, Sumbler, M G, and Ivimey-Cook, H C. 1990. A revised lithostratigraphy for the Lower and Middle Lias (Lower Jurassic) east of Nottingham, England. Proceedings of the Yorkshire Geological Society, Vol. 48, 121-141. |
| Ambrose, K. 2001. The lithostratigraphy of the Blue Lias Formation (Late Rhaetian-Early Sinemurian) in the southern part of the English Midlands. Proceedings of the Geologists' Association, Vol. 112, 97-110. |
| Carney, J N, Ambrose, K and Brandon A. 2002. Geology of the Melton Mowbray district - a brief explanation of the geological map. British Geological Survey Sheet Explanation, Sheet 142 (England and Wales). |
| Berridge, N G, Pattison, J, Samuel, M D A, Brandon, A, Howard, A S, Pharaoh, T C, and Riley, N J. 1999. Geology of the Grantham district. Memoir of the British Geological Survey, sheet 127 (England and Wales). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E127
E142
E126
|
