The BGS Lexicon of Named Rock Units — Result Details

Castle Eden Fissure-fill Formation

Computer Code: CEDN Preferred Map Code: notEntered
Status Code: Full
Age range: Mesozoic Era (MZ) — Cromerian Stage (QC)
Lithological Description: Breccia formed of limestone and dolostone together with sparse clasts of red mudstone filling subvertical karstic fissures in the limestone and dolostones of the Zechstein Group (formerly Magnesian Limestone) (Francis, 1970). Two distinct units occur. The lower "unfossiliferous fissure fills" are likely to be either Mesozoic or early Palaeogene in age as they are similar to evaporite dissolution breccias that occur elsewhere within the Permian limestones. The upper "fossiliferous fissure fills" contain clay, in addition to limestone debris, that has yielded assemblages of partially pyritized organic material including peat, seeds, tree trunks, ostrocods, mammalian bones and freshwater molluscs. The remains of over 100 species of plant have been identified from lower parts. Of this "Castle Eden Flora" 64% of the species no longer grow in Britain, or are extinct. This flora suggests an Early Pleistocene age, which is supported by the identification of Mammuthus meridionalis, an elephant that was common in Europe in the Early Pleistocene up to the Cromerian. Sparse glacial erratics of supposed Scandinavian origin have been found in fissure fill deposits south of Limekiln Gill [NZ 4776 3813].
Definition of Lower Boundary: Unconformable contact with underlying fractured limestones and dolostones of the Zechstein Group (formerly Magnesian Limestone). The fissures are generally linear, vary from 1 to 7 m wide and extend down to 25 m vertically through the limestone cliffs from rockhead, locally along faults. Other fissure fills are cylindrical in shape. Fissure walls commonly bear subvertical slickensides resulting from compaction and many of the fragments are striated and polished.
Definition of Upper Boundary: Channelled erosional, unconformable contact with overlying limestone-rich gravel of the Limekiln Gill Gravel Formation or planar subhorizontal, unconformable contact with dark grey stony sandy silty clay diamicton of the Blackhall Till Formation.
Thickness: Up to 25 m.
Geographical Limits: Coast of County Durham.
Parent Unit: Great Britain Superficial Deposits Supergroup (GBG)
Previous Name(s): Durham Fissure Fillings (-762)
Alternative Name(s): Blackhall Colliery Formation
Stratotypes:
Type Area  A 9 km stretch of cliff sections in the limestones and dolostones of the Zechstein Group (formerly Magnesian Limestone) between Hawthorn Hive and Crimdon Park, County Durham (Smith and Francis, 1967). 
Reference(s):
Bridgland, D R, Horton, B P and Innes, J B. 1999. The Quaternary of northeast England. Field Guide. Quaternary Research Assocation, London. 
Huddart, D. 2002. Warren House Gill. 51-56 in Huddart, D and Glasser, N F (editors), Quaternary of Northern England. Geological Conservation Review Series, No.25. [Peterborough: Joint Nature Conservation Committee.] 745pp. 
Smith, D B and Francis, E A. 1967. Geology of the country between Durham and West Hartlepool. Memoir of the Geological Survey of Great Britain, Sheet 27 (England and Wales). 
McMillan, A A, Hamblin, R J O, and Merritt, J W. 2011. A lithostratigraphical framework for onshore Quaternary and Neogene (Tertiary) superficial deposits of Great Britain and the Isle of Man. British Geological Survey Research Report, RR/10/03. 343pp. 
Francis, E A. 1970. Quaternary. 134-152 in Johnson, G A L, Geology of Durham County. [Newcastle: Natural History Society of Northumberland, Durham and Newcastle-upon-Tyne.] 152pp. 
Thomas, G S P. 1999. Northern England. 91-98 in Bowen, D Q (Editor), A revised correlation of Quaternary and Neogene deposits in the British Isles. Geological Society Special Report No.23. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable