The BGS Lexicon of Named Rock Units — Result Details

Scarlett Point Member

Computer Code: SCPT Preferred Map Code: notEntered
Status Code: Full
Age range: Asbian Substage (CR) — Asbian Substage (CR)
Lithological Description: The member is characterised by tabular beds of pale wackestone and calcisiltite. These beds, which can be cherty and pyritious, have gradational (locally dolomitised) boundaries with the interbedded black fissile, blocky claystones. 'Chondritiform' and Helminthoides burrows are common in the limestones. Inadunate crinoid lags and scattered ammonoids (Beyrichoceras or Bollandoceras) also occur, some preserved in a semi-buoyant resting position, with the venter resting on the former sea bed. Deposition was in a deep marine hemi-pelagic environment, but with periodic fine clastic and carbonate supply (gravitational).
Definition of Lower Boundary: Taken at the lowest black claystone, which is about 0.12m thick, overlying the fine-grained, pale mottled limestone (wackestone) of the Hodderense Limestone Formation at Scarlett Point [SC 2583 6633].
Definition of Upper Boundary: This is not exposed, so the nature of the upper boundary is therefore unknown. The overlying succession comprises black hemipelagic mudstones of the Bowland Shale Formation.
Thickness: 14m
Geographical Limits: The southern part of the Isle of Man, in the Castletown area, from Scarlett Point [SC 2583 6633] northwestwards to Poyllvaaish [SC 2440 6761]. Dinantian rocks in the northern part of the island are entirely concealed and hence it is unknown whether the unit is present in the north.
Parent Unit: Bowland Shale Formation (BSG)
Previous Name(s): Scarlett And Strandhall Beds (-3021)
Scarlett Beds [Obsolete Name And Code: Use SCPT] (SCLB)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Scarlett Point, where the Member is exposed in coastal sections. 
Reference(s):
Lewis, H P. 1930. The Avonian succession in the south of the Isle of Man. Quarterly Journal of the Geological Society of London, 86, 234-290. 
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. 
Dickson, J A D, Ford, T D and Swift, A. 1987. The stratigraphy of the Carboniferous rocks around Castletown, Isle of Man. Proceedings of the Yorkshire Geological Society, Vol.46, 203-229. 
Lamplugh G W. 1903. The geology of the Isle of Man. Memoir Geological Survey of Great Britain 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E400