Computer Code: |
ITCH |
Preferred Map Code: |
notEntered |
Status Code: |
Full |
Age range: |
Early Pleistocene (QPE)
— Holocene Epoch (QH) |
Lithological Description: |
Floodplain alluvium and river terrace deposits. The floodplain alluvium comprises overbank deposits of brown organic silty clay, together with peaty clay and peat, overlying sand and gravel. Tufa occurs as 1 to 2m-high raised hummocky spreads. The surviving river terrace deposits comprise sand and gravel, planar bedded or cross-bedded, locally overlain by overbank deposits of clayey and sandy silts and silty clays. These fine-grained deposits may be partly aeolian in origin. The major gravel lithology is flint, dominantly sub-rounded to sub-angular and a little well-rounded, and subordinate quartz, ironstone and "sarson". The sand fraction is composed of fine- to coarse-grained well-rounded quartz grains, with subangular flint in the coarse fraction. The older, higher terraces are commonly cryoturbated. |
Definition of Lower Boundary: |
Unconformable on Palaeogene and Cretaceous bedrock. |
Definition of Upper Boundary: |
Surface. |
Thickness: |
To c.12m |
Geographical Limits: |
The catchment of the River Itchen and its tributaries in the Southampton-Alresford area. |
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 valley of the River Itchen and its tributaries in the Southampton-Alresford area. Edwards and Freshney, 1987. |
Reference(s): |
Edwards, R A and Freshney, E C. 1987. Geology of the country around Southampton. Memoir of the British Geological Survey, Sheet 315 (England and Wales). |
Booth, K A. 2002. Geology of the Winchester District - a brief explanation of the geological map. Sheet Explanation of the British Geological Survey. 1:50 000 Sheet 299, Winchester (England and Wales). |
Farrant, A R. 2002. Geology of the Alreford district - a brief explanation of the geological map. Sheet explanation of the British Geological Survey. 1:50 000 sheet 300 Alresford [England and Wales]. 30pp. |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
E299
E300
E315
|