The BGS Lexicon of Named Rock Units — Result Details

Dee Valley Formation

Computer Code: DEEVA Preferred Map Code: notEntered
Status Code: Full
Age range: Devensian Stage (QD) — Holocene Epoch (QH)
Lithological Description: Alluvium of silt, sand and clay with some peat, grading to gravel towards the base. River Terraces are composed of silty sand or sandy gravel with rare clay.
Definition of Lower Boundary: Probably unconformable, irregular and in places strongly incised into lithologically variable sediments of the Caledonia or Albion Glacigenic groups or into bedrock.
Definition of Upper Boundary: Ground surface or unconformable below artificial deposits.
Thickness: To 10m
Geographical Limits: Cheshire, within the river valley and tributaries of the River Dee.
Parent Unit: Cheshire - North Wales Catchments Subgroup (CNWCA)
Previous Name(s): Tywi Formation (-2749)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Alluvium and river terrace deposits of the river valley and tributaries of the River Dee, Cheshire. McMillan et al., 2005. 
Reference(s):
McMillan, A A, Hamblin, R J O and Merritt, J W. 2005. An overview of the lithostratigraphical framework for the Quarternary and Neogene deposits of Great Britain (onshore). British Geological Survey Research Report RR/04/04. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable