| Computer Code: |
GRBL |
Preferred Map Code: |
Gby |
| Status Code: |
Full |
| Age range: |
Hettangian Age (JH)
— Sinemurian Age (JS) |
| Lithological Description: |
Grey calcareous mudstones with numerous thin, laterally persistent, shelly, bioclastic limestones occurring in groups and comprising more than 10% of the sequence. |
| Definition of Lower Boundary: |
Base of lowest limestone in unit; at 87.35m in type section, borehole F/B5 (SK95SW/17); at top of Barnby Member. |
| Definition of Upper Boundary: |
Top of highest limestone in unit; at 56.75m in type section borehole F/B5 (SK95SW/17), at base of Beckingham Member. |
| Thickness: |
30.60m in borehole F/B5. |
| Geographical Limits: |
East Midlands Shelf (south Yorkshire to London Platform area). |
| Parent Unit: |
Scunthorpe Mudstone Formation (SMD)
|
| Previous Name(s): |
Granby Limestones [Obsolete Name and Code: Use GRBL, SMD]
(-3440)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Reference Section |
Fulbeck Airfield Borehole F/B1 (SK85SE/25), depths 40.5 to 70.9m |
| Type Section |
Fulbeck Airfield Borehole F/B5 (SK95SW/17), depths 56.75 to 87.35m |
| 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. |
| Sumbler, M G, 1987. Geological Notes and Local Details for 1:10,000 Sheet SK85SE (Beckingham). British Geological Survey Technical Report. |
| Sumbler, M G, 1987. Geological Notes and Local Details for 1:10,000 Sheet SK95SW (Brant Broughton). British Geological Survey Technical Report. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E127
E142
|
