The BGS Lexicon of Named Rock Units — Result Details

Naburn Sand Member

Computer Code: NABS Preferred Map Code: notEntered
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: Mottled brownish yellow, yellowish brown, brown and grey silty, sporadically clayey fine to coarse sand. Characteristically poorly sorted and locally laminated. Grains dominated by quartz with sporadic plagioclase feldspar. Commonly shows a fining upwards sequence from lower boundary with underlying laminated clay.
Definition of Lower Boundary: Commonly sharply erosive, and characterised by a thin (<10mm) bed of coarse sand with rare gravel directly overlying mottled reddish brown and grey stiff laminated clay of the Hemingbrough Glaciolacustrine Formation
Definition of Upper Boundary: This unit is typically exposed at surface, or the upper boundary is represented by a gradational contact with fine-grained aeolian sand of the Sutton Sand Formation. This unit is inferred to thin and pinch out eastwards to the west of Elvington.
Thickness: Varies from <0.5m to 2.5m at Naburn flood alleviation pit [SE 59840 45280].
Geographical Limits: The Naburn Sand Member is distributed radially from Fulford, south of York to the east where it pinches out to the west of Elvington. The northern limit is marked by the York Moraine Member to the south of York. The southern limit is marked by the southwest to northeast trending Escrick Moraine Member [SE 584 407].
Parent Unit: Breighton Sand Formation (BREI)
Previous Name(s): Sand Of The 25 Foot Drift Of The Vale Of York (-3573)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Naburn Environment Agency flood alleviation excavation just to the south of Naburn Village at Herons Reach. Permanent but grassed over. Revealed 2.5m of yellowish brown, silty, fine to coarse sand, fining upwards. 
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 drawn in the Leeds Office of the Institute of Geological Sciences - Solid and drift ed. Provisional ed. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable