The BGS Lexicon of Named Rock Units — Result Details

Kentford Member

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 4m but in places for example at [TL 706 634] the deposits are at least 6m 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 400m north-west of Cock and Bull Farm, Kentford (BGS Registered No.TL76NW/93, 0-5.0m.) 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