| Computer Code: |
LEHA |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Guadalupian Epoch (PUG)
— Lopingian Epoch (PUL) |
| Lithological Description: |
The Leine Halite Formation consists of colourless, white, grey or pink, clear to translucent, locally opaque, generally hard and crystalline halite with interbedded and intergrown pink to red, opaque, hard K/Mg salts, principally sylvite and carnallite with some polyhalite. Minor beds of white to grey, soft to moderately hard, crystalline to amorphous anhydrite and red-brown to pale grey-brown, locally silty, saliferous, soft and amorphous mudstone have been recorded. |
| Definition of Lower Boundary: |
The base of the Leine Halite Formation is normally defined by a sharp downward change from colourless or pink halite to white to pale grey anhydrite and dolomitic anhydrite of the Hauptanhydrit Formation. This boundary is characterized on wireline logs by a sharp downward increase in velocity and density. Near the basin margin, where the underlying Hauptanhydrit Formation includes a significant proportion of mudstone, there is a less sharp change in velocity and density (e.g. 53/2-2). The gamma log generally shows a slight, occasionally marked, downward increase in values across the formational boundary, although in some wells there is no significant log break (e.g. 36/26-1). Where the Hauptanhydrit Formation is locally absent the Leine Halite Formation sits directly on the Plattendolomit Formation (e.g. 47/8-1). |
| Definition of Upper Boundary: |
The top of the Leine Halite Formation is defined by a downward change from red-brown, halite and K/Mg salt bearing mudstones of the Roter Salzton Formation to colourless, white, grey or pink halite with pink to red K/Mg salts. It is characterized by a sharp downward increase in velocity. Where halite occurs at the top of the Leine Halite Formation, the gamma log shows a sharp downward decrease in values (e.g. 36/26-1 and 41/25a-l). In wells where K/Mg salts occur at the top of the formation, the gamma log shows a sharp downward increase in values (e.g. 42/10-1 and 49/22-3). |
| Thickness: |
The Leine Halite Formation is up to around 300 m thick, although its depositional thickness is difficult to determine in the central part of the basin where sections have been extensively disrupted by halokinesis. It is absent over much of the Mid North Sea High. |
| Geographical Limits: |
The Leine Halite Formation is present throughout much of the Southern North Sea. |
| Parent Unit: |
Zechstein Group (ZG)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Reference Section |
North Sea well 36/26- 1: 1043.5-1071 m (3423-3513 ft) (Johnson et al., 1994). |
| Reference Section |
North Sea well 42/10a- 1: 1711.5-1970.5 m (5615-6465 ft) (Johnson et al., 1994). |
| Reference Section |
North Sea well 49/26- 4 (Rhys, 1974, table 2, fig. 3): 1596.5-1691.5 m (5238-5550 ft) (Johnson et al., 1994). |
| Reference Section |
North Sea well 50/21- 1: 1744.5-1903 m (5723-6244 ft) (Johnson et al., 1994). |
| Reference(s): |
| Johnson, H, Warrington, G and Stoker, S J. 1994. 6. Permian and Triassic of the Southern North Sea. In: Knox, R W O'B and Cordey, W G (eds.) Lithostratigraphic nomenclature of the UK North Sea. British Geological Survey, Nottingham. |
| NAM and RGD (Nederlandse Ardolie Maatschappij and Rijks Geologische Dienst) 1980. Stratigraphic nomenclature of the Netherlands. Transactions of the Royal Dutch Geological and Mining Society of Delft. |
| Rhys, G H. 1974. A proposed standard lithostratigraphic nomenclature for the southern North Sea and an outline structural nomenclature for the whole of the (UK) North Sea. Report of the Institute of Geological Sciences, 74/8. |
| Smith, D B. 1980. The evolution of the English Zechstein basin. In: Fuchtbauer, H, and Peryt, T M (eds.) The Zechstein basin with emphasis on carbonate sequences. Contributions to Sedimentology 9, 7-34. |
| Smith, D B, Brunstrom, R G W, Manning, D I, Simpson, S and Shotton, F W. 1974. A correlation of Permian rocks in the British Isles. Geological Society of London Special Report No. 5. |
| Smith, D B, Harwood, G M, Pattison, J and Pettigrew, T H. 1986. A revised nomenclature for Upper Permian strata in eastern England. 9-17 in Harwood, G M and Smith, D B (editors). The English Zechstein and Related Topics. Geological Society Special Publication No.22. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
