Computer Code: |
BPGR |
Preferred Map Code: |
notEntered |
Status Code: |
Full |
Age range: |
Anglian Stage (QA)
— Anglian Stage (QA) |
Lithological Description: |
Sand and gravel, with possible lenses of silt, clay or peat. [Generic description]. Horizontally stratified, matrix-supported gravel with thin tabular cross-bedded sand channels. Gravel assemblage is characterised by abundant angular flint (75-89%), sparse rounded flint (3-9%), sparse vein quartz (4-10%) and sparse quartzite (1-6%). |
Definition of Lower Boundary: |
Rests unconformably on bedrock geology (London Clay on Sheet 256). |
Definition of Upper Boundary: |
At surface. |
Thickness: |
1-6m, average 3m |
Geographical Limits: |
Thames Valley and associated tributaries. |
Parent Unit: |
Maidenhead Formation (MNHD)
|
Previous Name(s): |
none recorded or not applicable
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Type Area |
Black Park Country Park, Slough. Stratotype: up to 4m of gravel and sand. Gibbard, 1985. |
Reference(s): |
Gibbard, P L, 1985. Pleistocene history of the Middle Thames Valley. (London: Cambridge University Press.) |
Strange, P J. 1992. A new nomenclature for the River Terrace Deposits of North London. British Geological Survey Technical Report, WA/92/52. |
Gibbard, P L. 1989. The geomorphology of part of the Middle Thames forty years on: a reappraisal of the work of F Kenneth Hare. Proceedings of the Geologists' Association, Vol.100, 481-503. |
Hare, F K, 1947. The geomorphology of a part of the Middle Thames. Proceedings of the Geologists' Association, Vol.58, 294-339. |
Gibbard, P L. 1979. Middle Pleistocene drainage in the Thames Valley. Geological Magazine, Vol.116, 35-44. |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
E254
E256
E257
E268
|