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 [Obsolete Name and Code: Use DEEVA]
(-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 |