The BGS Lexicon of Named Rock Units — Result Details

Peveril Point Member

Computer Code: PEP Preferred Map Code: PEP
Status Code: Full
Age range: Berriasian Age (KR) — Berriasian Age (KR)
Lithological Description: Calcarenites and calcirudites (rich in bioclastic material) interbedded with carbonaceous clays. The base is defined by thickly-bedded, limestones containing fragmented shells (Upper Broken Shell Limestone Bed). This passes (and fines) upwards into a biomicrite and carbonaceous mud-dominated sequence with glauconite-rich beds, which, in the west, are commonly rich in detrital quartz (Unio Bed, Upper "Cypris" Clays and Shales Beds). The limestones in this part of the Member contain abundant Unio and Viviparus.
Definition of Lower Boundary: The lower boundary is marked by the first upward occurrence of thickly- bedded, coarse biosparite limestones (i.e. the base of the Broken Shell Limestone Bed) resting on muds and finer-grained biosparites or micrites at the top of the Stair Hole Member.
Definition of Upper Boundary: The top is marked by the last occurrence of significant limestone beds (containing Unio and Viviparus) beneath monotonous sandy mudstones of the Wealden Group.
Thickness: Between 7 and 17 m in Dorset.
Geographical Limits: Member defined in and limited to the Dorset coast region. Upwey to Swanage in Dorset.
Parent Unit: Durlston Formation (DURN)
Previous Name(s): Friar Waddon Member (-445)
Upper Purbeck Beds [Obsolete Name And Code: See PEP] (UPB)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Peveril Point, north end of Durlston Bay, Dorset. Westhead, R K and Mather, A E. 1996. 
Reference Section  Eastern part of Mupe Bay, Dorset. Westhead, R K and Mather, A E, 1996. 
Reference(s):
Westhead, R K and Mather, A E. 1996. An updated lithostratigraphy of the Purbeck Limestone Group in the Dorset area. Proceedings of the Geologists' Association, Vol.107, 117-128. 
Westhead, R K. 1993. Geology of the Dorchester (south) District. British Geological Survey Technical Report, WA/93/22. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E328 E341 E342 E343