| Computer Code: |
BMN |
Preferred Map Code: |
BrM |
| Status Code: |
Full |
| Age range: |
Sinemurian Age (JS)
— Pliensbachian Age (JE) |
| Lithological Description: |
[Obsolete: use CHAM] Mainly grey mudstones; includes scattered calcite mudstone nodules, and several continuous beds with abundant nodules of calcite mudstone, phosphate or siderite mudstone: also in type area two thin limestone beds, calcareous siltstone bed, and basal thin ferruginous oolite. |
| Definition of Lower Boundary: |
Erosive, non-sequential contact of Glebe Farm Bed with underlying Scunthorpe Mudstone Formation in type area. In north Lincolnshire, at top of Frodingham Ironstone. |
| Definition of Upper Boundary: |
Sharp contact with basal sandstone of Marlstone Rock Formation, in Grantham area. |
| Thickness: |
c. 110m in Type Area, thicker in Vale of Belvoir, thinning towards Humberside in north and London Platform to south. |
| Geographical Limits: |
East Midlands Shelf Area, from Humberside to London Platform. |
| Parent Unit: |
none recorded or not applicable
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
Coleby Mudstone Formation [Obsolete: use CHAM, WHM]
|
| Stratotypes: |
| Type Area |
Fulbeck area, Lincs: sequence based on mapping and ditch-dredgings-summarised by Brandon, and others, 1990, fig.5. |
| Reference Section |
Thorpe-By-Water Borehole (SP89NE/1), 5.6m to 125.86m. |
| Reference Section |
Copper Hill Borehole, Ancaster, (SK94SE/56), depth 68.48m to 182.60m. |
| 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. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E127
|
