The BGS Lexicon of Named Rock Units — Result Details

Hampshire Avon Formation

Computer Code: HAAV Preferred Map Code: notEntered
Status Code: Full
Age range: Early Pleistocene Epoch (QPE) — Holocene Epoch (QH)
Lithological Description: Floodplain alluvium and river terrace deposits. The floodplain alluvium comprises overbank deposits of mottled dark grey and orange organic silt, silty clay and clayey sand, tgether with peat, overlying sand and gravel. Fourteen river terraces are preserved. The river terrace deposits comprise very sandy gravels. The clasts are sub-angular to sub-rounded, poorly sorted up to 5cm in diameter, dominantly flint, with a little Upper Greensand chert, "sarsen" stone, vein quartz, Jurassic limestone, and well-rounded flints from the Palaeogene, in a matrix of clayey sand. Deposits of the higher terraces are cryoturbated.
Definition of Lower Boundary: The fluvial deposits rest unconformably on Palaeogene and Cretaceous strata.
Definition of Upper Boundary: Surface.
Thickness: To 8m, including up to 4m of alluvial overbank deposits.
Geographical Limits: The catchment of the Hampshire Avon and its tributaries.
Parent Unit: Solent Catchments Subgroup (SNTCA)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  The valleys of the Hampshire Avon and its tributaries from Christchurch to Warminster and Devizes. Bristow et al., 1991. 
Reference(s):
Reid, C. 1902. The geology of the country around Ringwood. Memoir of the Geological Survey of Great Britain, Sheet 314 (England and Wales). 
Clarke, M R. 1981. The sand and gravel resources of the country north of Bournemouth, Dorset. Description of parts of 1:25000 Sheets SU00, 10, 20, SZ09, 19 and 29. Mineral Assessment Report of the Institute of Geological Sciences, 51. 
White, H J O. 1917. Geology of the country around Bournemouth (2nd edition). Memoir of the Geological Survey of Great Britain, Sheet 329 (England and Wales). 
Bristow, C R, Freshney, E C and Penn, I E. 1991. Geology of the country around Bournemouth. Memoir for 1:50 000 geological sheet 329 (England and Wales). HMSO, London. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E266 E281 E282 E283 E297 E298 E314 E329