Åre Formation (Åreformasjonen)

(From NPD Bulletin no. 4)

Båt Group


From the Norwegian word for oar. This formation corresponds to the informal term Hitra formation ("the coal sequence" or Hl-1) together with the lower part of the Aldra formation (Hl-2).

Well type section

6507/12-1 (Saga Petroleum), coordinates 65°07'01.62"N, 07°42'42.61"E from 2920 m to 2412 m (Fig. 7). Two cores, 26.2 m recovery.

Well reference section

6407/1-2 (Statoil), coordinates 64°47'50.61"N, 07°02'23.76"E, from 4548 m to 4221 m (Fig. 8). No cores.


508 m in the type well. Generally between 300 m and 500 m.


Alternating sandstones and claystones are in-terbedded with coals and coaly claystones. The claystones are grayish or locally red brown and noncalcareous to very calcareous. The sandstones are grayish, very fine to coarse-grained and predominantly moderately to poorly sorted. The coals in the type well are dark brown to black, vitreous, brittle and locally pyritic.

Basal Stratotype

The base is defined directly underneath the lowermost coal bed identified on the sonic log. In the type well the resistivity log increases slightly and changes to a somewhat less nervous pattern at the transition into the Åre Formation.

Lateral extent and variation

The formation is present in all areas drilled in the Haltenbanken - Trænabanken region but seismic data indicate that it is truncated in positive areas such as the Nordland Ridge. The upper part of the formation contains a laterally continuous mudstone interval; this has a generally uniform thickness, but thins slightly to the north.


Rhaetian to Pliensbachian.

Depositional environment

Costal plain to delta plain deposits with swamps and channels pass upwards into marginal marine facies. Individual coals can be up to 8 m thick. More proximal lithofacies contain less coal and coarser sandstones. Shallow drilling to the east shows conglomerates which are probably laterally equivalent to the Å re Formation (Bugge et al. 1984).


The formation is partially equivalent to the Statfjord Formation in the North Sea, to the combined upper Fruholmen, Tubå en and Nordmela formations in the Hammerfest Basin and to the Kap Stewart Formation of eastern Greenland. The Åre Formation has a lower sand content than the Statfjord Formation in the northern North Sea.

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