The BGS Lexicon of Named Rock Units — Result Details
Byley Mudstone Member
| Computer Code: | BYM | Preferred Map Code: | ByM |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Anisian Age (TA) — Ladinian Age (TD) | ||
| Lithological Description: | Alternations of structureless reddish brown mudstone and laminated greenish grey and reddish brown mudstones. NOTE: The contact between the Byley Mudstones and overlying Wych Mudstones is not currently shown on British Geological Survey maps, and they have been mapped as one division. | ||
| Definition of Lower Boundary: | Top of Northwich Halite. | ||
| Definition of Upper Boundary: | Top of highest substantial laminated greenish grey and reddish brown bed in this formation; base of Wych Mudstones. | ||
| Thickness: | 180.90 m in Byley borehole (SJ 76 NW/7). | ||
| Geographical Limits: | Chesire Basin. | ||
| Parent Unit: | Sidmouth Mudstone Formation (SIM) | ||
| Previous Name(s): | Byley Mudstone Formation [Obsolete Name and Code: Use BYM]
(-2038)
Keuper Marl, Middle [Obsolete Name And Code: Use MMG] (MKM) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Reference Section | Crewe heat flow borehole (SJ65SE/6) 156-299.3 m depth. Core at British Geological Survey, Keyworth. | ||
| Reference Section | Wych Brook (Scars beside stream). | ||
| Type Section | Byley borehole (SJ76NW/7) 272.20 m - 453.10 m. | ||
| Reference(s): | |||
| Howard, A S, Warrington, G, Ambrose, K, and Rees, J G. 2008. A formational framework for the Mercia Mudstone Group (Triassic) of England and Wales. British Geological Survey Research Report, RR/08/04. | |||
| Wilson, A A. 1993. The Mercia Mudstone Group (Trias) of the Cheshire Basin. Proceedings of the Yorkshire Geological Society, Vol.49, 171-188. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E123 | |||