Tilje Formation (Tiljeformasjonen)

(From NPD Bulletin no. 4)

Båt Group


The Norwegian word for a boat's decking. This unit corresponds to the upper part of the informal Aldra formation (Hl-2).

Well type section

6507/11-1 (Saga Petroleum), coordinates 65°04'43.82"N, 07°29'23.33"E, from 2596 m to 2498 m (Fig. 9). Five cores (33 m recovery) were taken through the upper part of the formation.

Well reference section

6609/10-1, (Saga Petroleum), coordinates 66°14' 42.27"N, 09°14'59.50"E, from 1733 m to 1642 m (Fig. 10). One core (11.5 m recovery) was taken uppermost in the unit.


98 m in the type well, 91 m in the reference well.


Very fine to coarse-grained sandstones are in-terbedded with shales and siltstones. The sandstones are commonly moderately sorted with a high clay content and most beds are bioturbated. Shale clasts and coaly plant remains are common. Pure shale beds are rare; most of the finer grained interbeds are silty or sandy.

Basal Stratotype

The base of the Tilje Formation is defined at the top of a mudstone interval recognized in most wells on Haltenbanken. The overlying sequence shows a markedly higher sand content and a greater average thickness of individual sandstone bodies. The gamma ray log shows a shift to generally lower values and a slightly more blocky pattern over the boundary.

The mudstone interval is most pronounced on the Halten Terrace, but is often difficult to pick further east on the Trøndelag Platform. Coal beds are here developed at higher stratigraphic levels than on Halten Terrace, and the top of the highest coal bed is recommended as the formational boundary.

In the reference well from Trænabanken the formational base is taken at an upward shift in the gamma ray log from relatively irregular, high amplitude variations to more uniform, low amplitude and generally lower readings. Limestone interbeds are common below the boundary and much less frequent above in this area.

Lateral extent and variation

The formation is present both on Haltenbanken and Trænabanken, although it is locally absent on the Nordland Ridge due to erosion. The formation is uniformly developed throughout the Halten Terrace where it is from 100 m to 150 m thick, but it thins northeastwards to less than 100 m on the Trøndelag Platform. Shallow drilling close to the coast (Bugge et al. 1984) indicates time equivalent deposits dominated by coarse-grained elastics.


Sinemurian to Pliensbachian.

Depositional environment

Nearshore marine to intertidal environments are typical of the formation. Subcrops near the coast (Bugge et al. 1984) indicate a gradual transition to continental environments eastwards.


The Tilje Formation is comparable in age and lithology to the Neill Klinter Formation of East Greenland and to the lower part of the Stø Formation in the Hammerfest Basin.

home previous page