The BGS Lexicon of Named Rock Units — Result Details

Winterbourne Formation

Computer Code: WINT Preferred Map Code: notEntered
Status Code: Pending Upgrade
Age range: Bolsovian Substage (CC) — Bolsovian Substage (CC)
Lithological Description: Grey and red mudstones with common thin and lenticular beds of quartz-conglomerate and pebbly sandstone.
Definition of Lower Boundary: The base of the formation is taken at the top of the dark grey to black fisile mudstone of the Cambriense Marine Band (locally termed the Winterbourne Marine Band), overlain by grey and red mudstone, locally conglomerate and pebbly sandstone, of the Winterbourne Formation.
Definition of Upper Boundary: The grey and red mudstone, locally conglomerate and pebbly sandstone, of the Winterbourne Formation is overlain with a sharp, slightly erosive base, by the first lithic sandstone of "Pennant" type of the Downend Member
Thickness: 180m
Geographical Limits: Northern limb of Kingswood Anticline and Coalpit Heath Basin of Bristol Coalfield [ST 70 80].
Parent Unit: Warwickshire Group (WAWK)
Previous Name(s): Downend Formation (-4001)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Harry Stoke C [Downend] Borehole [ST67NE/1]: entire thickness of formation from 485.0m to 317.1m depth. Kellaway and Welch, 1993 
Reference(s):
Waters, C N, Brown, M A E, Dean, M T and Powell, J H. In press. Lithostratigraphical framework for Carboniferous successions of Great Britain (Onshore). British Geological Survey Research Report, RR/05/06. 
Kellaway, G A and Welch, F B A, 1993. Geology of the Bristol district. Memoir of the British Geological Survey Special Sheet [England and Wales]. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E250 E264