| Computer Code: |
HFA |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Aptian Age (KP)
— Aptian Age (KP) |
| Lithological Description: |
The member is an alternation of fine, argillaceous sands and sandstones overlain by siltstones and, at the top of the succession, claystone in a sequence of five fining-upward cycles. |
| Definition of Lower Boundary: |
The base is taken where olive-grey or brownish grey siltstone of the Atherfield Clay Formation is overlain by grey, argillaceous, fine-grained sandstone of the member. |
| Definition of Upper Boundary: |
The top is taken where claystone at the top of the highest cycle of the Hoes Farm Borehole is separated, at a burrowed erosion surface, from glauconitic, calcareously cemented, indurated, fine- to medium-grained sandstone, with phosphatic nodules at the base, of the undivided upper part of the Hythe Formation. |
| Thickness: |
Up to 12.7m thick at the type site and 12.5m in the Thakeham Borehole (TQ11NW/17). |
| Geographical Limits: |
Recognised in the Hoes Farm and Thakeham boreholes in West Sussex. Ruffell (1993) noted the member at Woolmer Hill [SU 8775 3322]. This member is not shown separately on BGS maps of the district. |
| Parent Unit: |
Hythe Formation (HY)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Reference Section |
Thakeham Borehole TQ11NW/17 [TQ 1084 1765]. The Hythe Formation including the Hoes Farm Member is encountered from the surface to 24.03m depth with the member being encountered from about 11.0m to the base. Young and Lake (1988, p.28, Figure 7). |
| Type Section |
Hoes Farm Borehole (BGS SU91NE/19), where the full thickness is encountered at 59.3m to 72.0m depth below surface. Bristow et al. (1987). |
| Reference(s): |
| Bristow, C R. 1994. The geology of the Duncton district. British Geological Survey Technical Report WA/94/17. |
| Bristow, C R, Morter, A A, and Wilkinson, I P. 1987. The stratigraphy and palaeontology of the Lower Greensand of the Hoes Farm Borehole, near Petworth, Sussex. Proceedings of the Geologists' Association, Vol. 98(3), 217-227. |
| Young, B and Lake, R D. 1988. Geology of the country around Brighton and Worthing. Memoir of the British Geological Survey, Sheet 318 and 333 (England and Wales). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
