| Computer Code: |
RISA |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Kimmeridgian Age (JD)
— Tithonian Age (JI) |
| Lithological Description: |
The member comprises thick-bedded, structureless, medium-grained, poorly to well sorted sandstones. It lacks bioturbation. Composition is sub-arkosic. The sandstones contain clay clasts and thinly interbedded laminated, fissile mudstones. |
| Definition of Lower Boundary: |
The base is defined by a sharp, down-section change from sandstones to dark grey, fissile mudstones (Kimmeridge Clay). The boundary is marked by a sharp, down-section increase in gamma-ray values and a sharp increase in velocity. |
| Definition of Upper Boundary: |
The top is defined by a sharp, down-section change from dark grey, fissile mudstones (Kimmeridge Clay) to sandstones. A down-section decrease in gamma-ray values and a sharp or transitional down-section decrease in velocity coincides with the boundary. |
| Thickness: |
Up to 55 m thick. |
| Geographical Limits: |
The Ribble Sandstone Member is confined to the Fulmar Field (Quadrant 30/16) in the Central Graben. |
| Parent Unit: |
Kimmeridge Clay Formation (KC)
|
| Previous Name(s): |
Ribble Unit
(-5173)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
North Sea well 30/16- 7 between 3262 and 3305 m below KB (Richards et al., 1993). |
| Reference Section |
North Sea well 30/16- 25 between depths 3087.5 and 3115 m below KB (Richards et al., 1993). |
| Reference(s): |
| Johnson, H D, Mackay, T A and Stewart, D J. 1986. The Fulmar Oilfield (Central North Sea): geological aspects of its discovery, appraisal and development. Marine & Petroleum Geology, 3, 99-125. |
| Mehenni, M and Roodenburg, W Y. 1990. Fulmar Field- UK: South Central Graben, North Sea. In: Beaumont, E A and Foster, N H (eds.) Structural traps IV. Tectonic and non-tectonic fold traps. 113-139. [American Association of Petroleum Geologists, Tulsa] |
| Stockbridge, C P and Grey, D I. 1991. The Fulmar Field, Blocks 30/16 and 30/11b, UK North Sea. In: Abbotts, I L (ed.) United Kingdom oil and gas fields, 25 years commemorative volume. Memoir of the Geological Society, London, 14, 309-316. |
| Richards, P C, Lott, G K, Johnson, H, Knox, R W O'B. and Riding, J B. 1993. 3. Jurassic of the Central and Northern North Sea. In: Knox, R W O'B and Cordey, W G (eds.). Lithostratigraphic nomenclature of the UK North Sea. British Geological Survey, Nottingham. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
