Kyrre Formation (new) (Kyrreformasjonen)
(From NPD Bulletin no. 5)
Shetland Group
Name
Named after Olav "Kyrre" Haraldson, a Norwegian king (A.D. 1067-1093).
Well type section
Norwegian well 25/1-1
from 3582 to 2997 m, coordinates N 59°53'17.40", E 02°04'42.70" (Fig. 33).
Part of one core (0.5 m), including the upper boundary.
Well reference sections
Norwegian well 35/3-2
from 2864 to 1665 m, coordinates N 61°51105.98", E 03°46'28.22" (Fig. 34).
No cores.
Norwegian well 24/9-1
from 3638 to 3117 m, coordinates N 59°16'09.48", E 01°41'31.18" (Fig. 35).
no cores.
Norwegian well 30/11-3
from 3162 to 2892 m, coordinates N 60°02'38.59", E 02°3ri5.47" (Fig. 36).
No cores.
Thickness
The formation is 585 m thick in the type well (25/1-1), 1199 m in well
35/3-2, 521 m in well 24/9-1 and 270 m in well 30/11-3.
Lithology
The formation consists of mudstones with occasional limestone beds.
Some sandstone beds are found in parts of the Agat area. The mudstones are
medium grey to grey, silty to calcareous, occasionally pyritic,
glauconitic or micaceous. The sandstones are clear to white, and very
fine to fine grained.
Basal stratotype
The lower boundary is defined by an increase in gamma-ray intensity and a
decrease in velocity from the Tryggvason
Formation into the Kyrre Formation (Fig. 33) due to changes in carbonate
content. The boundary is unconformable on structural highs, usually above
the Cromer Knoll Group.
Characteristics of the upper boundary
The upper boundary shows a decrease in gamma-ray intensity and an increase
in velocity from the Kyrre Formation upwards into the
Jorsalfare Formation (Figs. 33 and 34). This
log change is also a result of the higher carbonate content and the
presence of basal limestone beds in the Jorsalfare Formation.
Distribution
With the exception of the Gullfaks area, the formation is present in the
Viking Graben, on the Tartipen Spur and the western margin of the Horda
Platform.
Occurrences of formation tops in wells
Isochore map TRYGGVASON-KYRRE
Age
Late Turonian to Campanian.
Depositional environment
Open marine.
Remarks
The Kyrre Formation is time-equivalent with the Flounder Formation in
the western part of the central North Sea and the upper part of the
Hod Formation in the eastern part (Deegan & Scull
1977). It is also equivalent with the informal "formation D" of Deegan &
Scull (1977) (Fig. 6).
