| Computer Code: |
CARR |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Callovian Age (JC)
— Callovian Age (JC) |
| Lithological Description: |
Sandstones with subordinate siltstones and mudstones. Basal mudstone (up to 15 m thick) comprises dark grey, calcareous, micaceous, carbonaceous and pyritic mudstone with belemnites and marine bivalves. The mudstone coarsens up-section to siltstone and into fine- to medium-grained (occasionally coarse-grained), bioturbated sandstone, which comprises the upper part of the member. Locally, two or more upward-coarsening cycles occur within the sandstone unit. Calcareous ooliths, bivalves and belemnites are common at the top of the upper cycle. See Linsey et al. (1980), Stephen et al. (1993) and Stevens (1991). |
| Definition of Lower Boundary: |
The base is defined by a sharp down-section change from mudstones to sandstones (Louise Member, Beatrice Formation). The boundary is marked by a down-section decrease in gamma-ray values and a sharp increase in velocity. Occasionally the basal mudstone of the Carr Member is poorly developed and it is then difficult to locate the boundary without detailed biostratigraphy. In the extreme east of its distribution, the Carr Member appears to rest unconformably on the Dunrobin Bay Group. |
| Definition of Upper Boundary: |
The top of the member is defined by a sharp down-section change from mudstone (Heather Formation) to sandstone; a sharp down-section decrease in gamma-ray values and an increase in velocity. |
| Thickness: |
Up to c. 40 m. |
| Geographical Limits: |
Inner Moray Firth (North Sea Quadrants 11, 12, 17 and 18). |
| Parent Unit: |
Beatrice Formation (BETR)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
North Sea well 11/30a- 9 between the depths 2786.5 and 2832 m below KB (Richards et al., 1993). |
| Reference Section |
North Sea well 12/21- 2 between the depths 2136.5 and 2163.5 m (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. |
| Linsley, P N, Potter, H C, McNab, G and Racher, D. 1980. The Beatrice Oil Field, Inner Moray Firth, UK North Sea. In: Halbouty, M T (ed.) Giant oil and gas fields of the decade, 1968-1978. American Association of Petroleum Geologists, Memoir, 30, 117-129. |
| Stephen, K J, Underhill, J R, Partington, M A and Hedley, R J. 1993. The genetic sequence stratigraphy of the Hettangian to Oxfordian succession, Inner Moray Firth. In: Parker, J R (ed.) Petroleum geology of Northwest Europe: Proceedings of the 4th conference, 485-505. [Geological Society, London] |
| Stevens, V. 1991. The Beatrice Field, Block 11/30a, 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, 245-252. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
