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 [Obsolete Name and Code: Use MSYVA]
(-409)
Swettenham Formation [Obsolete Name and Code: Use CLCA, CNWCA, LUNV, MSYVA] (-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): | |||
| 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. | |||
| 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. | |||
| 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 | |||