| Computer Code: |
SEP |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Caradoc Series (O4)
— Caradoc Series (O4) |
| Lithological Description: |
Spherulitic and silicified welded rhyolitic tuff. |
| Definition of Lower Boundary: |
Taken at the sharp change from bedded tuff, lapilli-tuff and sandstone of the Newton Manor Sandstone Formation. |
| Definition of Upper Boundary: |
Overlain by other members of the Yottenfews Tuff Formation: immediately by laminated fine-grained sandstone. |
| Thickness: |
91m (uncorrected for structural dip or borehole deviation from vertical). |
| Geographical Limits: |
Sellafield borehole 7A (NY00SE/36) only. |
| Parent Unit: |
Yottenfews Tuff Formation (YOT)
|
| Previous Name(s): |
Sella Park Member [Obsolete Name and Code: Use SEP]
(-3667)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Sellafield borehole No.7A, BGS Registered No. NY00SE/36, 680.96-771.5m below Rotary Table Elevation, 627.90m-718.44m below OD. |
| Reference(s): |
| Millward, D, Beddoe-Stephens, B, Williamson, I T, Young, S R, and Petterson, M G. 1994. Lithostratigraphy of a concealed caldera-related ignimbrite sequence within the Borrowdale Volcanic Group of west Cumbria. Proceedings of the Yorkshire Geological Society, Vol.50, part 1, 25-36. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
