The BGS Lexicon of Named Rock Units — Result Details

Park Farm Clay Member

Computer Code: PAF Preferred Map Code: notEntered
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: Greyish brown to dark grey, slightly fissured, laminated, soft (0.2-2cm varves) silt and clay with rare fine sand layers. Horizons of fine-grained sand to 1m thick occur within the unit.
Definition of Lower Boundary: Observed in boreholes, this unit rests on either a sand and gravel lag deposit or directly on bedrock.
Definition of Upper Boundary: The Park Farm Clay Member is succeeded by the Lawns House Farm Sand Member, The contact with the Lawns House Farm Sand Member is typically sharp.
Thickness: To 16m
Geographical Limits: Vale of York, south of the Escrick Moraine between the rivers Ouse, Foulness and Humber where the Lawns Farm Sand Member is present, and extending northwards beneath the Escrick Moraine, the York Moraine and the tills of the Vale of York Formation.
Parent Unit: Hemingbrough Glaciolacustrine Formation (HEM)
Previous Name(s): Sand Clay Of 25 Foot Drift Of Vale Of York (-2967)
Alternative Name(s): Warp
Stratotypes:
Partial Type Section  250m wide section at north end of disused clay pit to west of Park Farm, 2.5km eastsoutheast of Stillingfleet. Shows 7m of greyish brown, laminated, glaciolacustrine silt and clay. Very little coarse material is present at this site. The deposit shows some sub-horizontal deformation and vertical fissures, which might be due to dewatering processes or glaciotectonism. The unit is capped by the Bielby Sand Member. 
Reference(s):
1:50k geological map of Selby (Sheet 71) (in prep): Selby Sheet Explantion (in prep). 
British Geological Survey, 1973. Sheet 71 Selby solid and drift/compiled and draw in Leeds Office of the Institute of Geological Sciences - Solid and drft ed. Provisional ed. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable