The BGS Lexicon of Named Rock Units — Result Details

Eldersfield Mudstone Formation [Obsolete Name And Code: Use SIM]

Computer Code: ELM Preferred Map Code: ElM
Status Code: Index Level
Age range: Anisian Age (TA) — Carnian Age (TC)
Lithological Description: Mainly structureless red-brown silty mudstones and siltstones in the upper part (c.130m); lower part comprises alternating structureless and laminated beds with common green beds. Thin sandstones common in basal 20m. Includes Droitwich Halite Member.
Definition of Lower Boundary: As for base of the Mercia Mudstone Group, where mudstone and siltstone become dominant over sandstone in transition with underlying Sherwood Sandstone Group.
Definition of Upper Boundary: Sharp or transitional junction from red mudstone to green beds of the overlying Arden Sandstone Formation.
Thickness: c.366m in Eldersfield Borehole; c.410m in Kempsey Borehole; 120-130m in eastern Warwickshire.
Geographical Limits: Worcester Basin (Gloucestershire to Hereford and Worcester) and Warwickshire.
Parent Unit: Mercia Mudstone Group (MMG)
Previous Name(s): Eldersfield Formation (-4022)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  BGS Eldersfield Borehole (cored) From 4.77-368.53m depth. (Barclay, W J and others, 1997; Worssam, and others, 1989). 
Reference Section  BGS Worcester Borehole. From 30m to base of borehole at 301.32m 
Reference Section  BGS Stowell Park Borehole. From 2577ft 1in. to 3553ft 4ins (785.49-1083.06m) depth (Green and Melville, 1956). 
Reference(s):
Worssam, B C, Ellison, R A and Moorlock, B S P. 1989. Geology of the country around Tewkesbury. Memoir of the British Geological Survey, Sheet 216 (England and Wales). 
Barclay, W J, Ambrose K, Chadwick, R A and Pharaoh, T C. 1997. Geology of the country around Worcester. Memoir of the British Geological Survey, Sheet 199 (England and Wales). 
Green, G W and Melville, R V. 1956. The stratigraphy of the Stowell Park Borehole (1949-1951). Bulletin of the Geological Survey of Great Britain, No.11, p.1-66. 
Warrington, G, Audley-Charles, M G, Elliott, R E, Evans, W B, Ivimey-Cook, H C, Kent, P E, Robinson, P L, Shotton, F W and Taylor, F M. 1980. A correlation of the Triassic rocks in the British Isles. Special Report of the Geological Society of London, No.13. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E199 E137 E058 E096