The BGS Lexicon of Named Rock Units — Result Details

Glen Dhoo Formation

Computer Code: GLDH Preferred Map Code: notEntered
Status Code: Full
Age range: Tremadoc Series (O1) — Tremadoc Series (O1)
Lithological Description: A pale grey mudstone, with a variable proportion of siltstone laminae and sandstone dispersed in thin; sandstone locally predominant in thin to thick-bedded packets; siltstone, massive, dominant locally; minor occurences of andesitic tuff and volcanic breccia
Definition of Lower Boundary: Faulted.
Definition of Upper Boundary: Faulted contact only with the Ladyport Formation, which is distinguished by a change from a siltstone/sandstone-dominated facies to a mudstone-dominated facies in the Ladyport.
Thickness: About 300 m thick.
Geographical Limits: Isle of Man.
Parent Unit: Manx Group (MANX)
Previous Name(s): Glion Cam Unit (-282)
Lonan And Niarbyl Flags, Glen Dhoo Flags And Cronkshamerk Slates (-283)
Lonan And Niarbyl Flags (-2206)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Upper and Glen Dhoo. Chadwick et al., 2001. 
Reference(s):
Woodcock N H, Morris J H, Quirk D G, Barnes R P, Burnett D, Fitches W R, Kennan P S and Power G M. 1999. Revised lithostratigraphy of the Manx Group, Isle of Man. 45-68 in 'In sight of the suture' the Palaeozoic geology of the Isle of Man in its lapetus Ocean context. Woodcock N H, Fitches W R, Quirk D G and Barnes R P [editors]. Geological Society of London, Special Publication No. 160. 
Geological Survey. 1898. Isle of Man. Sheet 36,45,46 and 57. Solid and Drift geology. 1:63 360 scale. Reprinted at 1:50 000 scale by Institute of Geological Sciences 1975 (Southampton: Ordnance Survey). 
Lamplugh G W. 1903. The geology of the Isle of Man. Memoir Geological Survey of Great Britain 
Simpson A. 1963. The stratigraphy and tectonics of the Manx Slate Series. Quarterly Journal of the Geological Society of London, Vol. 119, 367-400 
Chadwick, R A, Jackson, D I, Barnes, R P, Kimbell, G S, Johnson, H, Chiverell, R C, Thomas, G S P, Jones, N S, Riley, N J, Pickett, E A, Young, B, Holliday, D W, Ball, D F, Molyneux, S G, Long, D, Power, G M and Roberts, D H. 2001. Geology of the Isle of Man and its offshore area. British Geological Survey Research Report, RR/01/06. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E400