| Computer Code: |
DKSA |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Tithonian Age (JI)
— Berriasian Age (KR) |
| Lithological Description: |
Very fine to medium-grained, well sorted, well cemented, locally carbonaceous and weakly calcareous sandstones, interbedded with dark coloured, organic-rich mudstones typical of the Kimmeridge Clay. |
| Definition of Lower Boundary: |
The boundary is defined by the down-section decrease in the proportion of sandstone to mudstone and a down-section increase in gamma-ray values. A distinctly high gamma-ray mudstone unit separates the Dirk Sandstone Member from the Claymore Sandstone Member in the type section. |
| Definition of Upper Boundary: |
The top is marked by a downward change from mudstones to sandstones interbedded with mudstone, together with a decrease in average gamma values and an increase in velocity. |
| Thickness: |
Up to 28 m. |
| Geographical Limits: |
Known only in the Galley Field, Block 15/23. |
| Parent Unit: |
Kimmeridge Clay Formation (KC)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
North Sea well 15/23- 2 between the depths 3900 and 3928.5 m below KB (Richards et al., 1993). |
| Reference(s): |
| 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 |
