Molo Member

Nordland Group, Kai Formation

Eidvin, Bugge & Smelror: The Molo Formation, article


English/ Norwegian

Molo Member/ Mololeddet

Previous names

"Frøyrygg formation" by Askvik & Rokoengen (1985) and "Molo formation" by Gustavson & Bugge (1995).

Derivatio nominis

Named from the Norwegian word for breakwater (mole).

Original definition

The member is formally described herein.


The lithology varies considerably throughout its distribution area. In most well and boreholes from proximal parts (including type well 6610/3-1), the unit consists mainly of red to yellow coloured sand. Some sections also contain well-rounded, rust tinted pebbles. In some wells glauconitic sand and mica-rich sand are recorded. In the Draugen Field (Trøndelag Platform), where the distal part is investigated, the unit contains glauconitic sand, silt and clay (see reference well 6407/9-5).


A total thickness of 206 m in the type well is only sampled with five side-wall cores (Fig. x). In the reference well a total thickness of 117 m is sampled with ditch cutting samples at ten meters interval (Fig. x). Some short vibro cores are sampled in the Nordland Ridge area (Fig. x). Close to its northern boundary (block xxxx/x) the unit reaches more than 500 m (Fig. x).

Geographical distribution

The formation extends from the cost off Møre, along the inner Mid Norwegian shelf up to the Nordland Rigde and Lofoten area.

Type well

Well name



WGS84 coordinates: 66°55'29.70"N, 10°54'06.28"E
UTM coordinates:
UTM zone:

Drilling operator name

British Petroleum/Saga Petroleum

Completion date

Interval of type section (m)

From 555 m (base) to approximately 349 m (the top is not sampled and logged in the type well).

Thickness in type well (m)

Approximately 206 m

Reference well

Well name



WGS84 coordinates: 64°16'42.35" N, 07°44'14.66"E

Drilling operator name

Norske Shell


Lower boundary (basal stratotype)

The lower boundary is recognised by an abrupt change from greyish claystone of the Brygge Formation to grey mica-rich sand of the Molo Member. The lower boundary is at 559 m in the type well section. The boundary is marked by a strong negative spike on the gamma log, and is also shown by a marked positive spike on interval transit time.

Upper boundary (characteristics)

The upper boundary is not sampled and logged in the type well and it is only recognized on seismic lines.

Lower and upper lower boundaries in reference well sections

In the reference well the lower boundary is recognized by an abrupt change from grayish claystone to the Brygge Formation to dark (nearly black) glauconitic sand of the Molo Member. The boundary is further marked by an increase in the gamma ray response and a decrease in velocity readings.

The upper boundary is recognized by a marked decrease in velocity readings and a slight decrease in the gamma ray response into the overlying glacio-marine diamicton.


The member is dated as Early Miocene to Late Pliocene (Eidvin et al. in press).

Depositional environment

The member was deposited in a costal shallow marine to prograding deltaic environment, probably formed in a wave-dominated environment with extensive long-shore drift (Rokoengen et al. 1995; Bullimore et al. 2005).



Bullimore, S., Henriksen, S., Liestøl, F.M. & Helland-Hansen, W. 2005. Clinoform stacking patterns, shelf-edge trajectories and facies associations in Tertiary coastal deltas, offshore Norway: Implications for the prediction of lithology in prograding systems. Norwegian Journal of Geology 85, 169-187.

Gustavson, M. & Bugge, T. (1995). Geologisk kart over Norge, berggrunnskart VEGA, M 1:250 000. Norges Geologiske Undersøkelse.

Rokoengen, K., Rise, L., Bryn, P., Frengstad, B., Gustavsen, B., Nygaard, E. & Sættem, J. 1995. Upper Cenozoic stratigraphy on the Mid-Norwegian continental shelf. Norsk Geologisk Tidsskrift 75, 88-104.

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