| Computer Code: |
NARC |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Mid Pleistocene (QPM)
— Holocene Epoch (QH) |
| Lithological Description: |
The Nar Valley Formation encompasses the fluvial, lacustrine, organic and marine deposits of the Nar River and its tributaries. Floodplain alluvium comprises soft clay, silts and fine sands, with bodies of peat, overlying sands and gravels. River terrace deposits (Wormegay Member, Pentney Member and Marham Member of Lewis, 1999) comprise sands, gravelly sands and gravels, with the pebbles dominantly of angular to sub-rounded flint, and Chalk. Marine deposits ("Nar Valley Clay") comprise blue-grey finely laminated shelly silty clays; the underlying Nar Valley Freshwater Bed comprises grey fine-grained silty sands and silts and a compressed wood peat. |
| Definition of Lower Boundary: |
Unconformable on Mid Pleistocene glacial deposits, and on bedrock. |
| Definition of Upper Boundary: |
Surface. |
| Thickness: |
To c.5m |
| Geographical Limits: |
The entire catchment of the Nar River and tributaries, in Norfolk. |
| Parent Unit: |
Ouse-Nene Catchments Subgroup (ONCA)
|
| Previous Name(s): |
Nar Valley Clay [Obsolete Code: Use NARC]
(NV)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
The valley of the Nar River, Norfolk. Ventris, 1986. |
| Reference(s): |
| Lewis, S G. 1999. Eastern England. 10-27 in Bowen D Q (editor), A revised correlation of Quaternary deposits in the British Isles. Geological Society Special Report, 23. [London: Geological Society.] |
| Ventris, P A. 1986. The Nar Valley. 7-55 in West, R G and Whiteman, C A (editors), The Nar Valley and North Norfolk Field Guide. [Coventry: Quaternary Research Association.] |
| Ventris, P A. 1985. Pleistocene environmental history of the Nar Valley, Norfolk. PhD, University of Cambridge. |
| Gallois, R W, 1994. The geology of the country around King's Lynn and The Wash. Memoir of the British Geological Survey, Sheet 145 and part of 129 (England and Wales). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E160
E146
E145
E129
E159
|
