| Computer Code: |
KFRD |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Quaternary Period (Q)
— Quaternary Period (Q) |
| Lithological Description: |
Sand and gravel. In a borehole at Timworth Green [TL 8590 6923] BGS Registered No.TL86NE/82, they had a mean composition of 5 per cent 'fines', 55 per cent sand and 40 per cent gravel, but the lithology tends to be very variable. The gravel fraction is predominantly flint. |
| Definition of Lower Boundary: |
Generally unconformably overlying Chalk bedrock or chalky till. |
| Definition of Upper Boundary: |
At surface. |
| Thickness: |
Generally up to about 4 m but in places for example at [TL 706 634] the deposits are at least 6 m thick. |
| Geographical Limits: |
Within the valley of the River Lark at Timworth Green [TL 860 692] and its tributaries, the Kennet and the Black Bourn at Grimstone End [TL 934 696] Suffolk. |
| Parent Unit: |
Lark Valley Formation (LKVY)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
3rd Terrace Of River Lark (Bristow,1990)
|
| Stratotypes: |
| Type Section |
The stratotype is a borehole about 400 m north-west of Cock and Bull Farm, Kentford (BGS Registered No. TL76NW/93, 0-5.0 m). Clayton, 1983. |
| Reference(s): |
| 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. |
| 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). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E189
|
