| Computer Code: |
LFRD |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Quaternary Period (Q)
— Quaternary Period (Q) |
| Lithological Description: |
Sand and gravel, but also with beds of interbedded clay and silt. Typically about 6 per cent 'fines', 65 per cent sand and 29 per cent gravel. |
| Definition of Lower Boundary: |
Generally unconformably overlying Chalk bedrock or chalky till, but also overlying glacial silt infilling buried valleys. |
| Definition of Upper Boundary: |
At surface. |
| Thickness: |
Generally up to between about 4 and 5 m, but locally over 9 m thick. |
| Geographical Limits: |
Within the valley of the River Lark especially Hawstead, Bury St Edmunds, Lackford and Mildenhall, and the Lark tributaries, the Kennet and the Black Bourn. |
| Parent Unit: |
Lark Valley Formation (LKVY)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
1st Terrace Of River Lark (Bristow,1990)
|
| Stratotypes: |
| Type Section |
The stratotype is the north face of a gravel pit just south of the River Lark about 1 km north-east of Lackford. Bristow, 1990. |
| Reference(s): |
| Bowen, D Q. 1999. A revised correlation of Quaternary deposits in the British Isles. Geological Society Special Report, No. 23. |
| Bristow, C R. 1990. Geology of the country around Bury St Edmunds. Memoir of the British Geological Survey, Sheet 189 (England and Wales). |
| Clayton, A R. 1983. The sand and gravel resources of the country between Maidenhall and Barrow, Suffolk: description of 1:25000 Sheets TL76, TL77 and part of TL87. Mineral Assessment Report, 123, Institute of Geological Sciences, London. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E189
|
