The BGS Lexicon of Named Rock Units — Result Details

Dalby Group

Computer Code: DALBY Preferred Map Code: notEntered
Status Code: Full
Age range: Wenlock Epoch (SW) — Wenlock Epoch (SW)
Lithological Description: Sandstone (wacke), thin- to medium-bedded with interbedded siltstone and mudstone, locally including laminated carbonaceous siltstone and thin beds of meta-bentonite.
Definition of Lower Boundary: Visible contacts are all faulted against the Manx Group and Peel Formation. It is likely that both lower and upper stratigraphical contacts are unconformable - the lower on the Manx Group where distinguished by being sandstone-dominated facies as opposed to a mudstone, the upper probably with overlying Permian or Triassic red-bed facies.
Definition of Upper Boundary: Not seen, -see lower boundary details.
Thickness: About 1200 m thick.
Geographical Limits: Isle of Man.
Parent Unit: Not Applicable (-)
Previous Name(s): Manx Slate Series (-3975)
Manx Slates [Obsolete Name And Code: See MANX] (MXSL)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  The Niarbyl to Glen Maye. Morris et al., 1999. 
Reference(s):
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). 
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. 
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 
Morris J H, Woodcock N H and Howe M P A. 1999. The Silurian succession in the Isle of Man: the late Wenlock Niarbyl Formation, Dalby Group. 189-211 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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E400