Johansen Formation (new)

(From NPD Bulletin no. 3)

Dunlin Group

Name

Named after Hjalmar Johansen, member of the Amundsen South Pole expedition.

Well type section

Norwegian well 31/2-1 (Shell), from 2176 m to 2272.5 m, coord N 60°46' 19.16'', EO3°33'15.87", (Fig. 13).

Well reference section

None at present.

Thickness

95.5 m in the type well.

Lithology

In the type well the formation consist of a sequence of sandstones with thin calcite cemented streaks throughout. The lower part is medium to fine-grained, micaceous, well sorted sandstone which grades downwards into light grey silty micaceous claystone. The main section of the formation is composed of medium grained, friable sandstones, with well sorted quartz grains which are angular to subrounded. The uppermost part is composed of medium to fine grained, micaceous sandstones, which are moderately sorted, silty and argillaceous.

Boundaries

In the type well area the Johansen Formation splits the Amundsen Formation. It is distinguished by a low response, crescentic gamma ray profile.

Distribution

The formation is restricted to an area extending from the eastern part of the Horda Platform northwards to the Malay Fault Blocks.

Age

Sinemurian to Pliensbachian.

Depositional environment

The formation was probably deposited on a high energy, shallow marine shelf.

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