| Computer Code: |
COLLF |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Quaternary Period (Q)
— Quaternary Period (Q) |
| Lithological Description: |
Massive or brecciated silty clay or interlayered sand and silty clay, representing estuarine deposits and mud flats and sand flats. |
| Definition of Lower Boundary: |
Conformably overlies the Creeting Sand - junction taken at change from sand lithology to interbedded silt and clay. |
| Definition of Upper Boundary: |
Overlain unconformably by Lowestoft Formation chalk-rich till. Very distinct change of lithology across junction. In places overlain unconformably by sands and gravels of the Kesgrave Formation. |
| Thickness: |
Up to 3.75 m thick. |
| Geographical Limits: |
Restricted to area around Great Blakenham, Suffolk. |
| Parent Unit: |
Norwich Crag Formation (NCG)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Former face in quarry, at Great Blakenham, other more recent sections may still be present (Allen, 1984). |
| Reference(s): |
| Allen, P. 1984. Field guide to the Gipping and Waveney valleys, Suffolk, May, 1982. Cambridge, Quaternary Research Association. |
| Gibbard, P L, Allen, P, Field, M H, and Hallam, D F. 1996. Early Pleistocene sediments at Great Blakenham, Suffolk, England. Quaternary Science Reviews, Vol. 15(5-6), 413-424. |
| Moorlock, B S P, Riding, J B, Hamblin, R J O, Allen, P, and Rose, J. 2002. The Pleistocene College Farm Silty Clay at Great Blakenham, Suffolk, England - additional information on the course of the early River Thames. The Netherlands Journal of Geosciences, Vol.81, 9-17. |
| Field, M H. 1992. Azolla tegeliensis Florschutz from the early Pleistocene of the British Isles. Geological Magazine, Vol. 129(3), 363-365. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
