| Computer Code: |
NSFS |
Preferred Map Code: |
notEntered |
| Status Code: |
Index Level |
| Age range: |
Arnsbergian Substage (CG)
— Arnsbergian Substage (CG) |
| Lithological Description: |
Fine-grained sandstone (quartz arenite), well-sorted, thinly planar bedded and laminated, cross-bedded and ripple cross-laminated in places, with wave and current ripples. In the Steeton [SE04SW] and Cowling [SD94SE] areas the sandstone is medium-grained, medium-bedded and feldspathic. |
| Definition of Lower Boundary: |
The base is gradational. with an upward coarsening succession of dark grey silty mudstone and grey siltstone with thin beds of sandstone that become more common upwards. The base of the Nesfield Sandstone is placed where sandstone becomes predominant over siltstone. |
| Definition of Upper Boundary: |
Sharp transition from Nesfield Sandstone quartz arenite to overlying dark grey mudstone with up to three marine bands, the Nuculoceras nuculum marine bands (E2C 2-4) between 10 and 20m above the top of the sandstone. |
| Thickness: |
To 20m: thickest near Addingham [SE 09 05]. |
| Geographical Limits: |
West Yorkshire area [Nesfield, near Ilkley]. |
| Parent Unit: |
Silsden Formation (SILS)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
River Wharfe at Addingham from 200m upstream of Low Mill Village weir to 200m downstream of the weir. Sandstone is 6m thick in this section (Martinson, 1990). |
| Reference(s): |
| Martinson, O J, 1990. Interaction between eustacy, tectonics and sedimentation with particular reference to the Namurian E1c - H2c of the Craven-Askrigg area, Northern England. Unpublished PhD thesis, University of Bergen, Norway. |
| Stephens, J V, Mitchell, G H and Edwards, W N. 1953. Geology of the country between Bradford and Skipton. Memoir of the Geological Survey of Great Britain, Sheet 69 (England and Wales). |
| Waters, C N, 2000. Geology of the Bradford district. Sheet description of the BGS. 1:50000 Series, Sheet 69 Bradford (England and Wales). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E069
|
