Fangst Group (Fangstgruppen)

(From NPD Bulletin no. 4)


Norwegian name for catch. Previous informal name was the Tomma formation (Hl-4).

Type area

The Halten Terrace. The group's development is illustrated by the type section of its basal unit in well 6507/11-3 (Saga Petroleum), coordinates 65°01'59.8"N, 07°30'42.34"E, from 2536 m to 2412 m (Fig. 16). Reference wells for the group are 6407/1-2 (Statoil), coordinates 64°47'50.61"N, 07°02'23.76"E, from 3907 m to 3658.5 m (Fig. 17), and 6507/12-1 (Saga Petroleum), coordinates 65°07'01.62"N, 07°42'42.61"E, from 2213 m to 2094 m (Fig. 18).


The Fangst Group typically comprises three li-thological units: a lower fine to medium-grained sandstone with numerous shaly interbeds, a middle mudstone, and an upper relatively massive fine to coarse-grained sandstone. Each of these units are defined as formations herein.

Basal Stratotype

The base of the group is defined by the base of the Ile Formation as described below.

Lateral extent and variation

The Fangst Group is represented in most of the Trænabanken - Haltenbanken area except on the highest parts of the Nordland Ridge where its constituent units have been eroded. Time-equivalent sandstone-dominated sequences subcrop on the sea-floor along the inner part of the Trøndelag Platform (Bugge et al. 1984) and outliers of Middle Jurassic sediments are present east of the Froan islands and beneath Beitstadfjorden in Trøndelag. The latter probably represent a continental facies equivalent to the dominantly marine Fangst Group.

Along the southern margin of the Nordland Ridge (e.g. the Heidrun Field) the succession is much thinner than on Halten Terrace and the threefold lithologic division is not so obvious. Further north the Trænabanken wells show a lateral facies change to marine mud-stone of the Viking Group and only the lower unit of the Fangst Group (the Ile Formation) is recognized.


Late Toarcian to Bathonian.

Depositional environment

Shallow marine to coastal/deltaic facies dominate sequences on the Halten Terrace. Increasing continental influence is inferred towards the Trøndelag Platform to the east, especially in the lower part of the group. Upper parts interfinger with marine shales to the northeast in the Trænabanken area.


The Fangst Group corresponds generally to the Brent Group in the North Sea and to the Stø Formation on Tromsøflaket. However, the basal part of Stø Formation is older and the base of the Brent Group is slightly younger than the Fangst Group.


Although three formations are described herein it is clear that increasing knowledge will lead to the establishment of a more varied framework to reflect the lateral facies changes seen in the area.

Ile Formation
Not Formation
Garn Formation

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