The BGS Lexicon of Named Rock Units — Result Details

Mersey Valley Formation

Computer Code: MSYVA Preferred Map Code: notEntered
Status Code: Full
Age range: Devensian Stage (QD) — Holocene Epoch (QH)
Lithological Description: Probably silt, sand and clay (with peat in places) Alluvial sediments grading to gravel at base. River terraces are composed of gravel or gravelly sand.
Definition of Lower Boundary: Probably unconformable, irregular and in places strongly incised into lithologically variable sediments of the Caledonia and Albion Glacigenic groups or into bedrock.
Definition of Upper Boundary: At the ground surface or unconformable below artificial deposits.
Thickness: Generally less than 10m but locally in excess of 20m.
Geographical Limits: Cheshire and south Lancashire within the river valley and tributaries of the River Mersey west of the Peak District.
Parent Unit: Cheshire - North Wales Catchments Subgroup (CNWCA)
Previous Name(s): Mersey High Terrace (-409)
Swettenham Formation (-4546)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Alluvium and river terrace deposits of the valley and tributaries of the River Mersey west of the Peak District. Tributary valleys include the Dane, Goyt, Etherow and Irtwell. 
Reference(s):
Thomas, G S P. 1999. Northern England. 91-98 in Bowen, D Q (Editor), A revised correlation of Quaternary and Neogene deposits in the British Isles. Geological Society Special Report No.23. 
Harvey, A M. 1985. The river systems of northwest England. 122-139 in Johnson, J R (Editor), The Geomorphology of northwest England. [Manchester: Manchester University Press.] 
Johnson, R H. 1969. A Reconnaissance Survey of some River Terraces in parts of the Mersey and Weaver Catchments. Manchester Literary and Philosophical Society (Memoirs and Proceedings), Vol.112, 1969-1970. 
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