The BGS Lexicon of Named Rock Units — Result Details

Johnston Intrusive Complex

Computer Code: JOIN Preferred Map Code: notEntered
Status Code: Index Level
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Intrusions of quartz diorite, tonalite, granite,and pegmatite, with some hybrid rock types.
Definition of Lower Boundary: Not applicable; contacts mostly faulted.
Definition of Upper Boundary: Not applicable.
Thickness: Unknown.
Geographical Limits: Southwest Wales, Pembrokeshire.
Parent Unit: Not Available (!)
Previous Name(s): Johnston Complex (-984)
Johnston Diorite Complex (-985)
Johnston Series (-986)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Johnston railway cutting Strahan et al., 1914 
Reference(s):
Strahan A, Cantrill T C, Dixon E E L, Thomas H H and Jones O T. 1914. The geology of the South Wales Coalfield. Part XI. The country around Haverfordwest. Memoir of the Geological Survey of Great Britain. (London: HMSO). 262pp. 
Bevins, R E, Pharaoh, T C, Cope, J C W and Brewer, T S. 1985. Geochemical character of Neoproterozoic volcanic rocks in southwest Wales. Geological Magazine, Vol.132, 339-349. 
Baker, J W. 1982. The Precambrian of south-west Dyfed. 15-25 in Geological Exclusions in Dyfed, South-west Wales. Bassett, M G (Editor). (Cardiff: National Museum of Wales). 
Thorpe, R S. 1972. Possible subduction zone origin for two Precambrian calc-alkaline plutonic complexes from southern Britain. Bulletin of the Geological Society of America, Vol. 83, 3663-3668. 
Pharaoh T C and Gibbons W. 1994. Precambrian rocks in England and Wales south of the Menai Strait Fault System. 85-97 in Gibbons W and Harris A L (editors), A revised correlation of Precambrian rocks in the British Isles. Geological Society of London Special Report No.22. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E227 E228