| Computer Code: |
HFFL |
Preferred Map Code: |
HfF |
| Status Code: |
Full |
| Age range: |
Sinemurian Age (JS)
— Sinemurian Age (JS) |
| Lithological Description: |
One to two bluish grey, weathering yellowish brown, silty, slightly sandy, shelly limestone beds 0.02 to 0.8 m thick, separated by mudstone (0.35m thick in type section). Both limestone and mudstone contain pyritic shells and debris and the limestones include much amorphous pyrite. Fauna includes bivlaves (including common pectiniids and numerous Gryphaea), ammonites, belemnites, ostracods and echinoderms. Forms a weak feature. |
| Definition of Lower Boundary: |
Change up from grey mudstone with small phosphatic nodules and ammonites, and large limestone nodules of the undifferentiated Foston Member; at 13.11 m depth in type section Fulbeck Airfield Borehole (SK95SW/17). |
| Definition of Upper Boundary: |
Change up into grey mudstone of the undifferentiated Foston Member; at 12.59 m depth in type section Fulbeck Airfield Borehole (SK95SW/17). |
| Thickness: |
0.1 to 1.5 m; 0.52 m in type section. |
| Geographical Limits: |
East Midlands: north Leicestershire to Linclonshire. Not recognised in the Scunthorpe Mudstone Formation of 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: |
Foston Member (FSTL)
|
| Previous Name(s): |
Highfield Farm Limestone [Obsolete Name and Code: Use HFFL]
(-3466)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Fulbeck Airfield Borehole F/B5 (SK95SW/17). |
| Reference(s): |
| 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). |
| 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). |
| 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. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E127
E142
E126
|
