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Svarte Formation (new) (Svarteformasjonen)

(From NPD Bulletin no. 5)

Shetland Group


Named after Halvdan Svarte, King of Ringerike, Norway about A.D. 850.

Well type section

Norwegian well 25/1-1 from 3995 to 3807 m, coordinates N 59°53'17.40", E 02°04'42.70" (Fig. 33). No cores.

Well reference sections

Norwegian well 35/3-2 from 3447 to 3207 m, coordinates N 61°5r05.98", E 03°46'28.22" (Fig. 34). No cores.
Norwegian well 24/9-1 from 3992 to 3804 m, coordinates N 59°16'09.48", E 01°47'31.18" (Fig. 35). No cores.


In the Viking Graben, the formation is 188 m thick in the type well 25/1-1, 240 m in well 35/3-2 and 188 m in well 24/9-1.


The formation generally consists of mudstones interbedded with limestones. Sandstones occur in the Agat area. The content of limestones relative to mudstones is generally lower in the northern than in the southern part of the Viking Graben. The mudstones are medium to light grey, often calcareous, occasionally micaceous, glauconitic and pyritic. The limestones are mainly white to medium grey, argillaceous or sandy. The sandstones are clear to light grey and often cemented by calcite.

Basal stratotype

The lower boundary shows a general upward decrease in gamma-ray intensity and an increase in velocity from the Cromer Knoll Group into the Svarte Formation (Fig. 34). This is due to a higher content of carbonate in the Svarte Formation.

Characteristics of the upper boundary

The upper boundary is generally easily located, and is characterised by an increase in gamma-ray intensity and a distinct decrease in velocity from the Svarte Formation up into the Blodøks Formation (Fig. 33). This is caused by a lower carbonate content in the Blodøks Formation.


The formation is present in the Viking Graben and north of the Tampen Spur towards the Marulk Basin. It is, however, lacking on structural highs such as the Lomre Terrace (e.g. Norwegian wells 35/8-1 and 35/8-2), (Nybakken and Backstrøm, in press).

Occurrences of formation tops in wells



Depositional environment

Open marine.


The Svarte Formation is time-equivalent with the Hidra Formation in the central North Sea and with the informal "formation A" of Deegan & Scull (1977) (Fig. 6).

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