Vol. 8 pp 33-59, Geol. Surv. Denmark and Greenland Bulletin

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Lithostratigraphy

The upper Pleistocene in the Vendsyssel region com-
prises three major stratigraphic units: (1) a unit of
marine sediments deposited on the erosional surface
of the Saalian till, overlain by (2) a glacioterrestrial
succession that in turn is succeeded by (3) a second
marine deposit. The first marine unit was laid down
after the retreat of the ice from the region at the end
of Saalian time. During Eemian and Early to Middle
Weichselian time, the Older Yoldia Sea prevailed (Jes-
sen et al. 1910; Jessen 1918). From the end of the
Middle Weichselain to the latest Late Weichselian, the
area was subjected to terrestrial glaciation (Houmark-
Nielsen et al. 1996). After the ice melted back from
the Main Stationary Line, a marine environment was
re-established and persisted until isostatic rebound
resulted in subaerial exposure of the seabed of the
Younger Yoldia Sea (Jessen 1918; Figs 12, 13).

A new lithostratigraphical subdivision is proposed

to cover the three upper Pleistocene successions (Fig.
14). The systematic stratigraphic framework is based
on formations defined according to the guidelines
given by Rawson et al. (2002). The lower marine unit,
corresponding to the deposits representing the Older
Yoldia Sea and formerly referred to as the Skærum-
hede series (Jessen et al. 1910), is here defined as the
Skærumhede Group (new group). The group includes
the Middle Weichselian Stortorn and Lønstrup Klint
Formations (new formations) and an unnamed lower
unit mainly including the Eemian and Lower Weich-
selian deposits (Figs 15, 16). Four formations are dis-
tinguished in the glacioterrestrial unit: the glaciofluvi-
al and glaciolacustrine Rubjerg Knude Formation (new
formation), the Kattegat Till Formation (Houmark-Niel-
sen 1987, 1999, 2003), the Ribjerg Formation (new
formation) and the Mid Danish Till Formation (Hou-
mark-Nielsen 1987, 1999, 2003). The uppermost ma-
jor unit, comprising the post-glacial arctic marine
younger Yoldia clay and Saxicava sand of Jessen (1918,
1931), is referred to the Vendsyssel Formation (new
formation) (Fig. 14).

Skærumhede Group

new group

History. The Skærumhede Group includes most of the
lithological units formerly described as the Skærum-
hede series (Jessen et al. 1910). These include the
marine Eemian, the marine Lower Weichselian and
the marine-brackish-lacustrine beds in the Middle
Weichselian (Figs 14, 15; Lykke-Andersen & Knudsen
1991; Knudsen 1994). Recognition of the group is pri-
marily based on a research borehole behind the farm
at Skærumhede, about 10 km west of Frederikshavn
(Fig. 13), that was drilled by the Geological Survey of
Denmark to investigate the source of natural gas in
the vicinity of Frederikshavn (Jessen et al. 1910). The
well penetrated to a depth of 235 m and terminated in
Upper Cretaceous chalk. Above the chalk, a 20 m thick
unit of till and glacial sediments was encountered.
The till is now referred to the Saalian (Lykke-Andersen
1987), and forms the basal unit of the Quaternary suc-
cession over most of north Jylland (Fredericia 1982,
1983a, b; Pedersen 1989).

The succession above the Saalian glacial sediments

was described under the heading: 'The marine Skæ-
rumhede series' by Jessen et al. (1910 pp. 67, 156).
This unit is c. 123 m thick, from 57.4 m to 180.3 m
below surface, corresponding to a lower boundary at
157.1 m and a top at 34.2 m below sea level. It was
subdivided into three biostratigraphic zones: 1) the
Turritella terebra zone (74 m thick), 2) the Abra niti-
da zone (8.5 m thick) and 3) the Portlandia arctica
zone (40 m thick) (Jessen et al. 1910). Additional de-
tails were added to the unit based on several glacio-
tectonically dislocated outcrops in the northern part
of Vendsyssel by Jessen et al. (1910) and Jessen (1918,
1931).

Subsequent discussion concerning the stratigraphic

position and differentiation of the Skærumhede se-
ries resulted in a new borehole, which was directed
by the Geological Survey of Denmark at the Skærum-
hede locality in the early 1970s. Although the bore-
hole only went down to 120 m below surface, it gave
a good record of the lithology and macrofauna and in
particular provided samples for a detailed foramini-
feral investigation (Bahnson et al. 1974).

Facing page (p. 32):

Fig. 14. Schematic stratigraphic log of the units represented in
the Rubjerg Knude Glaciotectonic Complex. The fossils

indicated on the log represent ¹⁴C-dated samples.

Name. The Skærumhede Group is named after the
locality of Skærumhede c. 10 km west of Frederiks-
havn, Denmark (Fig. 13).

Type section. The type section is defined as the Skæ-
rumhede well (DGU No. 10.4 and 10.392) (Fig. 15),
where the pioneer drill site for natural gas was situ-
ated at a barren and unfertile place caused by seep-
age of gas from the subsurface (Fig. 13; Jessen et al.

1910).

Reference sections. Reference sections are proposed in

well-documented borehole sections: the Nørre Lyng-
by II well (DGU No. 8.137) described by Lykke-Andersen

(1987), and the Skagen III well (DGU No. 1.287) re-
corded by Knudsen (1994) and Petersen (2004) (Fig. 16).

Lithology. The Skærumhede Group consists of rather
uniform bluish-black to dark grey clay with minor in-
tercalations of silt and fine-grained sand. The silt lam-
inae and thin fine-grained sand beds become more
common towards the top of the group. Macrofossils

Vendsyssel Formation

Rubjerg Knude Formation

Lønstrup Klint Formation

Stortorn Formation

Skærumhede
Group (undiff.)

Clay

Silty mud

Dropstones
in mud

Sandy mud

Sand

Till

Gravel

Chalk

Skærumhede Group

100

110

120

130

140

150

160

170

180

190

200

210

220

230

clay

silt

sand

cobble

pebble

f m c

SKÆRUMHEDE WELL

Weichselian

U. Cretaceous

Saalian

Eemian

m below surface (e. 23 m a.s.l.)

Marine fossil

Fig. 15. Lithostratigraphic log of the Skærum-

hede well DGU No. 10.4, the type section of
the Skærumhede Group and the Stortorn

Formation.

are present through most of the group but decrease
in abundance towards the top (Jessen et al. 1910). Drop-

stones are present in the middle of the group and
increase in abundance towards the uppermost part,
in which graded silts and sands are intercalated with
grey mud.

Boundaries. The lower boundary is the unconformity
on top of the Saalian till. The upper boundary is an
unconformity overlain by coarse clastic sediments in-
terpreted as a residual boulder bed (Unit B of Sadolin
et al. 1997).

Thickness. The thickness of the group varies from
nearly 130 m in the type section in the Skærumhede
well, to c. 48 m in the Nørre Lyngby well and c. 45 m
in the Skagen III well (Fig. 16).

Distribution. Knowledge of the distribution of the
group in the vicinity of Rubjerg Knude is based on
the Skærumhede well (DGU No. 10.4), the Nørre Lyng-
by well (DGU No. 8.137) and the Skagen well (DGU
No. 1.287; Figs 13, 16). The group is also known from
wells in the northern part of Vendsyssel and the islands

of Læsø and Anholt in the Kattegat. According to these
records, the group extends from the western part of
the Kattegat at Frederikshavn and Læsø, towards the
south central part of Vendsyssel, from where it con-
tinues offshore between Anholt and Djursland (Knud-
sen 1994, fig. 3). The group extends offshore into the
strait between Læsø and the Swedish coast. The south-
ward extent is not known, but is probably up to about
30 km south of Anholt. The extent to the north is also
uncertain and has not yet been mapped. It is inferred
that it may occur in the western part of the Skagerrak
(Knudsen 1994) and it may also extend out into the
northern part of the North Sea.

Age. The age of the group extends from the beginning

of the Eemian, about 130 000 years B.P. (Knudsen 1994),

to the latest part of the Middle Weichselian, about 30 000

years B.P. (Houmark-Nielsen 1999).

Depositional environment. At the lower boundary of
the group, red corroded flints were recognised in the
Skærumhede well (Jessen et al. 1910) indicating that
the top surface of the Saalian till had been exposed
and subjected to subaerial erosion prior to the trans-
gression that culminated in the Eemian. During the
Eemian, a deep-water shelf environment was estab-
lished with water depths exceeding 100 m; in the Ear-

ly Weichselian, water depths decreased dramatically
to less than 50 m (Knudsen 1994). The decrease in
water depth continued during the Middle Weichse-
lian under increasing glacial influence.

Subdivisions. The upper Skærumhede Group is sub-
divided into the Stortorn and Lønstrup Klint Formations.

The lower part of the group, mainly including the ma-

rine Eemian and Lower Weichselian deposits, is pres-
ently undifferentiated.

Stortorn Formation

new formation

History. In the Lønstrup Klint section, two units of
grey-bluish clay subjected to glacial deformation have
been distinguished, the diluvial clay and the Portlandia
arctica clay (Jessen 1931). The latter unit corresponds
to the so-called Older Yoldia Clay (Ældre Yoldialer in
Danish), which in the Skærumhede well was referred
to as the Portlandia arctica zone and in the cross-
section of Lønstrup Klint is indicated to occur at three
localities (Jessen 1931). The most impressive of these
is the Stortorn site, where dark grey - black clay, rich
in mollusc shells, crops out (Fig. 21). The site is inac-
cessible, or difficult of access, since the slippery clays
occur in the breaker zone at the foot of the almost
vertical cliff section. The other two localities are the
cliff sections just beyond the town Lønstrup, locally
named 'Lille Blå' (little blue), and the cliff section be-
low the northern corner of the Mårup churchyard. At
all three sites, the unit is tectonically disturbed which
hampers detailed logging of the succession. In addi-
tion, the formation occurs locally in the lower thrust-
sheet duplexes north of Mårup Church and in the
Moserende cliff section (see description of that sec-
tion, below).

Name.

The formation is named after the Stortorn cliff

section at Lønstrup Klint. The formation is here incor-
porated within the lowermost thrust unit in the Stor-
torn Section (see below).

Type section. The type section for the formation is the
Skærumhede well, DGU No. 10.4 (Figs 14, 15).

Reference sections. The reference sections for the for-
mation are the outcrops at Stortorn and north of the
northern corner of Mårup churchyard (Fig. 17) in the

mud sand

f. m. c.

gr.pb.co.

0 m

Sandy mud

Sand

Dropstones in mud

Gravel

Shells

Lamination

Structureless

Climbing ripples

Trough
cross-bedding

Ball-and-pillow /
convolute bedding

Thrust fault

Clayey mud

Current ripple
cross-lamination

Vendsyssel Formation

Dune sand

Lønstrup Klint Formation

Skærumhede
Group

X AAR 4069

Stortorn Formation

Unconformity

Thrust zone

Fig. 17. Sedimentological log of the succession in the southern part of the Ribjerg Section (above the 'Store Blå'). The Stortorn

Formation records an arctic marine deposit, yielding shells typical of this environment: Hiatella arctica, Mya truncata and Portlan-
dia arctica . The boundary between the Stortorn and Lønstrup Klint Formations constitutes a thrust-fault breccia indicating differen-

tiation into thrust-fault duplex segments of the Skærumhede Group. The Vendsyssel Formation at the top of the section was
deposited on an erosional unconformity with a lag conglomerate at the base. The location of the sample collected for ¹⁴C dating

(AAR 4069) is indicated (see Table 2).

Facing page:

Fig. 16. Simplified lithological logs from three thoroughly documented wells in Vendsyssel (Nørre Lyngby: DGU No. 8.137; Skærum-
hede: DGU No. 10.4; Skagen: DGU No. 1.287, for location see Fig. 13). The logs illustrate the stratigraphic correlation of the units

defined in the investigation of the Rubjerg Knude Glaciotectonic Complex. The difference in thickness of Eemian-Weichselian
deposits mainly reflects the average content of sand; the Skagen well represents a deeper marine depositional environment com-

pared to the Skærumhede well. Note that the Cretaceous deposits in the Skagen well comprise Turonian-Cenomanian greensands.
The figure is based on information from Jessen et al. (1910), Bahnson et al. (1974), Lykke-Andersen (1987), Lykke-Andersen &

Knudsen (1991), Knudsen (1994) and Petersen (2004).

Lønstrup Klint coastal cliff. The Nørre Lyngby well (DGU

no 8.137, Lykke-Andersen 1987) is the well closest to
Stortorn where the undisturbed formation has been

penetrated. Additional sections include the coastal cliff
at Hirtshals displaying allochthonous peats in the black
clay formation, and the Skagen III well (DGU no 1.287;
Petersen 2004) that includes a clay unit, 8 m thick, here

referred to the Stortorn Formation (Fig. 16).

Lithology. The Stortorn Formation consists of black,
locally

dark grey - bluish structureless clay with a large

number of dropstones, which are commonly glacially
striated. Lenses or irregular beds, up to 10 cm thick,
of shell debris (gravel-size) occur scattered in the unit,
and the abundance of shells in local patches gives the
formation a white spotted appearance (Fig. 18). At the

top of the formation, the clayey mud changes colour
fr om dark bluish grey to violet-brown and develops
recognisable lamination.

Fossils. The unit has been referred to the Portlandia
arctica zone of Jessen et al . (1910) since this is the
most abundant mollusc species in the clay (Bahnson
et al. 1974). Macoma calcarea is another common
mollusc and Hiatella arctica occurs in abundance. A
list of characteristic molluscs and their distribution in
the unit is given by K.S. Petersen (in: Bahnson et al.
1974). Moreover, the presence of Balanus sp . and
additional erratic macrofossils are reported. The most
common microfossils are the foraminifers Elphidium

excavatum and Cassidulina crassa . P.B. Konradi and
K.L. Knudsen (in: Bahnson et al . 1974) documented and

discussed the foraminiferal fauna.

Boundaries. The lower boundary of the formation is
defined by a shift from clayey mud to mud with a
marked increase in coarse-grained ice-rafted debris.
The increased content of coarse-grained material is
associated with an abundance of mollusc shells and
fragments. The upper boundary of the formation is
defined at the transition from marine clay showing
diffuse lamination and colours varying from grey blue-
green to violet-brown, to a grey clayey and silty mud
intercalated with graded silt and fine-grained sand
laminae a few millimetres thick.

Thickness.

The formation is about 20 m thick. In the

Skagen III well, the formation is only about 8 m thick,
probably due to the more offshore position and deeper
water environment in this part of the basin (Petersen
2004).

Distribution. The distribution of the Stortorn Forma-
tion is identical with the distribution of the Skærum-
hede Group. The formation can be readily identified in

the Nørre Lyngby well (Lykke-Andersen 1987; Figs 13,

16) and it has also been described from the Hirtshals
cliff section (Lykke-Andersen 1971). In addition, it is
known from the deeper wells in the main part of the
Vendsyssel area and from the islands of Læsø and An-

Hiatella shells

5 cm

Fig. 18. The Stortorn Formation in the

Stortorn Section is dominated by black
sticky clay. Locally, shells of Hiatella

arctica and Portlandia arctica are very
abundant. Dropstones are also common

in the formation. Photograph: August
2001.

holt (Fredericia 1982, 1983a, b, 1984; Lykke-Andersen

1987).

Age. Three shell samples from the Stortorn Formation
at Lønstrup Klint have been ¹⁴C dated, using the Atomic

Mass Spectrometric (AMS) method, for the present in-

vestigation. Two of the samples were derived from the

archives of the former Geological Survey of Denmark;
two shells of Hiatella arctica were chosen for dating
the formation at the Stortorn locality and from the north-

ernmost outcrop of the formation at Lønstrup Klint
('Lille Blå', at the base of the northern part of the Ri-
bjerg Section, collected and described by A. Jessen)
(Table 2). The third sample was taken in 1996 and
comprises shells of Hiatella arctica from the shell-
bearing clay outcrop at Stortorn (reference DGU no.
00136, AAR-4069, Table 2). These were dated to test
the collection made nearly 100 years earlier and pro-
vided an age for the lowermost Stortorn Formation,
namely 31 300 (± 400) years B.P. The age of the upper
levels of the formation, as represented by the muddy
sediments at the 'Lille Blå' section is slightly younger
(30 000 (± 400) years B.P. (Table 2)). The new dating
of the Stortorn Formation corresponds well with pre-
vious age dates from the upper part of the Skærum-
hede Group, which gave 32 000 years B.P. (Seidenkrantz
& Knudsen 1993).

Depositional environment. The presence of a boreal
fauna including Mytilus edulis , Arctica islandica and
Zirphaea crispata in the shell-debris gravel in an en-
vironment characterised by a bottom fauna of Port-
landia arctica and Macoma calcaria led Nordmann
(1928) and Jessen (1931) to conclude that the boreal
shallow-water faunas of interglacial affinity were trans-
ported as ice-rafted material into more offshore arctic
marine environments. The most convincing examples
of such erratic material are the dropstones with Bala-
nus sp. The Stortorn Formation is thus interpreted to
have been deposited during a period of decreasing
water depths in a marine environment characterised
by dispersal of erratics from drifting icebergs.

Lønstrup Klint Formation

new formation

History. The characteristic development of this forma-
tion, viz. grey clayey muds interbedded with layers of
fine-grained sand, occurs in the steeply inclined sheets

that are prominent in the cliff of Lønstrup Klint. Due
to the absence of macrofossils, this unit was named
Diluvialler (diluvial clay) and the unit was correlated
with the uppermost part of the Skærumhede Group in

the Skærumhede well (Jessen et al. 1910; Jessen 1918,
1931). The sedimentology of the formation was descri-

bed from Sandrende at Lønstrup Klint under the head-
ing Unit A by Sadolin et al. (1997).

Name. The formation is named after the coastal cliff
of Lønstrup Klint.

Type section. The type section for the formation is at
Sandrende in Lønstrup Klint, situated between point
3500 and 3600 m in the Rubjerg Knude cross-section
(Plate 1), from where a sedimentological log was pro-
vided by Sadolin et al. (1997) (Figs 13, 19).

Reference sections. Reference sections are defined at
Ulstrup Rende (Fig. 20) and at Kramrende (Fig. 21)
situated at 5950 m and 4500 m, respectively, in the
Rubjerg Knude cross-section (Plate 1). Moreover, the
Skærumhede and the Skagen wells are reference sec-
tions for the western and northern development of
the formation (Fig. 16).

Lithology. The formation consists of blue-grey clayey
and silty laminated mud and cross-laminated beds of
fine sand. The lowest part of the formation is charac-
terised by dark grey mud, interlayered with laminated
to thin-bedded clayey and silty mud. The light grey
beds, 1-5 cm thick, grade upwards from light grey silt
to dark grey clay (Fig. 22). Some of the dark grey
clayey mud levels are interbedded with thin lenticu-
lar, light-coloured silt and fine-grained sand laminae
(Fig. 23). Silty to fine-grained sandy beds may be up
to 1 m thick. Dropstones occur scatter ed in the blue-
grey mud. In the upper part of the formation, beds of
light grey sand, 3-8 m thick, occur interbedded with
a few thin beds of laminated mud. The thick sand
beds are characterised by climbing ripple cross-lami-
nation. In the cliff section at Rubjerg Knude, much of
the primary bedding in the Lønstrup Klint Formation
is disturbed by water-escape structures (ball-and-pil-
low etc.) and hydrodynamic brecciation (flame to dia-
pir structures).

Fossils. Macrofossils have not been found in the for-
mation and the foraminifers, dominantly Elphidium
excavatatum , are interpreted to be redeposited (Lykke-
Andersen 1987).

mud sand

f. m. c.

gr.pb.co.

0 m

L/R-unconformity

Sandy mud

Sand

Gravel

Basal till

Lamination

Structureless

Climbing ripples

Trough
cross-bedding

Slump structures

Ball-and-pillow /
convolute bedding

Thrust fault

Rubjerg Knude Formation

Lønstrup Klint
Formation

Kattegat Till Formation

Clayey mud

Current ripple
cross-lamination

Fig. 19. Sedimentological log of the

succession in the Sandrende Section,
including the type sections of the

Lønstrup Klint and Rubjerg Knude
Formations. The Lønstrup Klint For ma-

tion represents lacustrine deposition,
whereas the Rubjerg Knude Formation

records a shift from fluvial to lacustrine
sedimentation, returning to fluvial

sedimentation in the upper levels
(Sadolin et al. 1997). Note the synsedi-

mentary small-scale thrust structures that
appear in the upper levels of the

Rubjerg Knude Formation indicating that
the formation was deposited in a

piggyback basin.

Boundaries. The lower boundary of the Lønstrup Klint
Formation is placed at the transition from the typical
marine clay with a macrofossil fauna of the Stortorn
Formation to unfossiliferous laminated clayey and silty
muds with laminae and thin beds of fine sand. The
upper boundary is the marked erosional unconform-
ity between the Lønstrup Klint and Rubjerg Knude For-

mations, referred to as the L/R-unconformity (Figs 14,
24).

Thickness. The maximum thickness of the formation
is about 25 m, but with large variations due to erosion-

al relief at the L/R-unconformity.

Distribution. The Lønstrup Klint Formation is distri-
buted over the main part of Vendsyssel. It is erosion-
ally truncated at the top towards the south where un-
derlying glacial deposits or Upper Cretaceous chalk
constitute the surface geology of the coastal areas north
of Limfjorden. To the east, it probably extends off-
shore into the middle part of Kattegat from where it is
known in wells on the islands of Læsø and Anholt
(Lykke-Andersen 1987; Knudsen 1994). The extent out
into the North Sea to the west remains unknown.
Towards the north, it extends offshore into the Ska-
gerrak beyond Skagen, where it is recorded in the
Skagen III well (Petersen 2004).

0 m

mud

sand

f. m. c.

gr. pb.co.

Glacitectonite

Rubjerg Knude Formation

Ulstrup glaciofluvial beds

Lønstrup Klint Formation

Clayey mud

Sandy mud

Sand

Gravel

Lamination

Current ripple
cross-lamination

Trough
cross-bedding

Tectonite

Water-escape pipes
and sand-filled cracks

Structureless sediment

L/R-unconformity

Fig. 20. Sedimentological log of the succession in the southernmost thrust sheet in the Ulstrup Section. The log was measured at
Ulstrup Rende, situated at point 5980 m in the cross-section (Plate 1). Note the 4 m thick sand-crack dominated thrust zone that

characterises the lower part of the Lønstrup Klint Formation, which developed during thrust-sheet translation along the hanging-
wall flat (Figs 46, 47). Note also that in the Rubjerg Knude Formation, the lowermost 7 m corresponds to the glaciofluvial 'Ulstrup

beds' (Figs 28, 29).

Age. ¹⁴C dating of plant debris from the formation indi-

cates an age of about 30 000 B.P. (Houmark-Nielsen et

al. 1996). This age is compatible with the 32 000 B.P.

age derived from the underlying Stortorn Formation.

Depositional environment. The transition from the Stor-
torn Formation to the non-fossiliferous Lønstrup Klint
Formation is interpreted as a shift from a normal, arc-
tic marine environment through brackish to a fresh-
water environment dominated by rapid deposition of
suspended sediment supplied to the basin by melt-
water. The sharp-based normally graded silt and sand

beds are interpreted as fine-grained turbidites. The
dark mud was deposited from suspension, whereas
the lenticular sand/silt laminae represent wave-re-
worked, distal storm-sand layers. Sedimentation start-
ed below storm-wave base and it is suggested that
the lake environment was deep and of fairly wide
extent. The occurrence of numerous fine-grained sandy
turbidites sourced mainly from the south probably
reflects exposed land areas in the southern part of
Vendsyssel during the low stand of sea level (Sadolin
et al. 1997). The sand beds are interpreted to record
relatively rapid sedimentation by sediment gravity

0 m

Thrust zone

Rubjerg Knude Formation

Lønstrup Klint Formation

Sandy mud

Sand

Gravel

Lamination

Structureless

Climbing ripples

Trough
cross-bedding

Ball-and-pillow /
convolute bedding

Tectonite

Clayey mud

Current ripple
cross-lamination

mud

sand

f. m. c.

gr.pb. co.

L/R-unconformity

Fig. 21. Sedimentological log of the Lønstrup Klint and Rubjerg Knude Formations in the KR01 thrust sheet in the souther n part of
the Kramrende Section (point 4500 in Plate 1). The fine-grained, thin- to medium-bedded sandy turbidites in the Lønstrup Klint

Formation are interbedded with thin layers of blue-grey silty mud. These sand beds are often disrupted into ball-and-pillow load
structures (see Fig. 48). Note the tectonite at the base of the succession, related to the hanging-wall flat of the KR01 thrust sheet.

flows in a glaciolacustrine environment; the thickest
of these beds may represent deposition within one
summer of sediment derived from the southern slopes
of the basin (Sadolin et al. 1997).

Hydrodynamic deformation of the strata was initia-

ted at a very early stage in the glaciotectonic process,
as loading by the superposed Rubjerg Knude Forma-
tion and by glaciotectonic thrust sheets resulted in
increasing pore-water pressure. Hydrodynamic brec-
ciation continued during deformation until the dis-
placements of thrust sheets ceased.

Upper Weichselian lithostratigraphic
units

Rubjerg Knude Formation

new formation

History. In the steep cliff section at Rubjerg Knude,
the thrust sheets, consisting of the grey-blue coloured
clay of the Lønstrup Klint Formation, are deposition-
ally overlain and structurally underlain by light-col-
oured yellowish sand, named Diluvialsand (diluvial
sand) by Jessen (1918, 1931). The succession was re-

Fig. 22. Laminated to thin-bedded clayey

and silty mud in the lower part of the
Lønstrup Klint Formation in the Rubjerg

Knude Fyr Section. The bedding is
defined by layers grading from light

grey silt to dark grey clay, and the
sharp-based normally graded beds are

interpreted as fine-grained turbidites.
The coin for scale is 2.5 cm in diameter.

Photograph: September 1985.

Fig. 23. Dark grey clayey mud interbed-

ded with thin lenticular, light coloured
silt and fine-grained sand laminae. The

mud was deposited from suspension,
whereas the lenticular laminae represent

wave-reworked, distal storm-sand layers,
deposited below storm-wave base.

Photograph: June 1993.

Fig. 24. The L/R-unconformity is steeply inclined in the GR08 thrust sheet. Note the large-scale cross-bedding in the basal unit of the
Rubjerg Knude Formation, which onlaps the unconformity (R-onlap). Photograph: June 1993; rucksack for scale.

L/R-unconformity

0 m

Ulstrup glaciolacustrine beds

Lønstrup Klint Formation

Rubjerg Knude Formation

Thrust zone

mud

sand

f. m. c.

gr.pb. co.

Sandy mud

Sand

Gravel

Lamination

Structureless sediment

Trough
cross-bedding

Ball-and-pillow
convolute bedding

Water-escape pipes
and sand-filled cracks

Thrust fault

Clayey mud

Current ripple
cross-lamination

Fig. 25. Sedimentological log of the succession in the northern thrust sheet in the Ulstrup Section. The log was measured near the

Ulstrup steps at point 5625 m in the cross-section (Plate 1). The base of the log is the hanging-wall flat of the UL02 thrust sheet and
the lower most 2 m constitute the thrust zone. The boundary between the Lønstrup Klint Formation and the Ulstrup glaciolacustrine

beds above (lower unit of the Rubjerg Knude Formation) is a flat, non-erosional surface but can be traced to the northern part of the
UL02 thrust sheet where this boundary is a clear erosional unconformity.

ferred to as units B-D in the sedimentological study
by Sadolin et al. (1997).

Name . The formation is named after Rubjerg Knude,
the highest part of the Lønstrup Klint cliff..

Type section . The type section is at Sandrende in the
Lønstrup Klint cliff section (Figs 13, 19).

Reference section. Four reference sections are defined,
all situated in the vicinity of Rubjerg Knude. In the
distal part of the Rubjerg Knude Glaciotectonic Com-
plex, two reference sections are defined at Ulstrup.
The first of these is located in Ulstrup Rende at point

5900 m in the Rubjerg Knude cross-section (Plate 1)
which demonstrates the presence of coarse-grained
glaciofluvial channel fill deposits (Fig. 19). The second

reference section at Ulstrup is located at point 5450 m
in Plate 1 and documents the occurrence of fine-grained

clayey muddy glaciolacustrine beds in the Formation
(Fig. 25). The third reference section is situated at
Martørv Bakker (point 4850 m in Plate 1), which dem-
onstrates diamictitic sediments including slump units
in a piggyback basin (Fig. 26). The fourth reference
section is located at Moserende at point 1750 m in
Plate 1. This section illustrates the formation in a pig-
gyback basin situated in a proximal position in the
Rubjerg Knude Glaciotectonic Complex (Fig. 27).

mud

sand

f. m. c.

gr.pb. co.

0 m

Vendsyssel Formation

Holocene peat ( martørv )

Aeolian sand

Rubjerg Knude Formation
(including diamict sediments
and slump-folded units)

Lønstrup Klint Formation

L/R-unconformity

Erosional unconformity

Sandy mud

Sand

Gravel

Lamination

Structureless sediment

Trough
cross-bedding

Mud with scattered
pebbles and cobbles

Slump structures

Ball-and-pillow
convolute bedding

Clayey mud

Current ripple
cross-lamination

Fig. 26. Geological log of the diamict sediments and slump-fold structures, which represent the Rubjerg Knude Formation in the
piggyback basin on the back of the MB02 thrust sheet in the Martørv Bakker Section, point 4880 in the cross-section (Plate 1).

Lithology. The dominant lithology of the formation is
fine- to medium-grained sand. Beds of gravel occur in
the lower most 1-5 m, related to the initial deposition
succeeding the formation of the erosional unconform-
ity (the L/R-unconformity) (Figs 24, 27, 28, 29). The
sediment source was partly the main central part of
the Danish Basin, indicated by the content of 23-25%
flint and Upper Cretaceous chalk, and partly outwash
material from the propagating ice margin, indicated
by the c. 75% basement clasts (Jessen 1931). Many
sand beds display small-scale current ripple lamina-
tion, and some show well-developed climbing ripples
(Sadolin et al. 1997). Large-scale cross-bedded sand is
observed in shallow channel fills, and some trough
cross-stratification occurs in relation to growth-fault
structures formed along normal faults or depressions
related to the formation of synsedimentary footwall
synclines (see Fig. 87). A series of large-scale accre-
tionary cross-stratification structures are related to a
shift in the substratum inclination during thrust-fault

propagation (see Figs 82, 95). Clasts of clay derived
from the Lønstrup Klint Formation are common, and
in some of the syntectonic settings these beds rich in
clay-clasts may be regarded as sedimentary clastic brec-
cias with olistoliths or lumps of sandy mud 1-5 m in
size (Fig. 56). The olistoliths represent the frontal parts
of thrust sheets, which gravity-glided out into depres-
sions formed during thrust-fault propagation. Locally,
some of the depressions developed into small glacio-
lacustrine basins characterised by interbedded fine-
grained sands and sandy muds with current cross-
lamination; these deposits may reach a thickness of
up to 5 m (Fig. 25).

Fossils. Redeposited fossils occur together with accu-
mulations of twigs and amber ('ravpindelag'). Well-
preserved arctic mosses suitable for ¹⁴C dating the for-

mation have been separated from the organic debris
(Houmark-Nielsen et al 1996). In the basin at Stens-
næs, a large number of the mollusc shells were re-

L/R-unconformity

mud

sand

f. m. c.

gr.pb. co.

0 m

Sandy mud

Sand

Gravel

Lamination

Structureless sediment

Climbing ripples

Trough
cross-bedding

Slump structures

Ball-and-pillow
convolute bedding

Anastomosing joints

Thrust fault

Rubjerg Knude Formation

Lønstrup Klint Formation

Clayey mud

Current ripple
cross-lamination

Fig. 27. Geological log of sediments and thrust faults in the MR03 thrust sheet in the Moserende Section (point 1750 in Plate 1).

garded as a redeposited inter glacial fauna by Jessen
(1931). Among the shells are Astarte sp. , Cardium sp .,
Arctica islandica, Leda per nula, Mya Truncata, Hia-
tella arctica ; a full list of this diverse fauna is given in
Jessen (1931, p. 63). An Astarte sp. shell (AAR-4066)
was ¹⁴C dated to 43 000 ± 1300 years B.P. (Table 2),

which must be regarded as close to an infinite age,
thus supporting the suggestion of Jessen (1931) that
these shells represent redeposited interglacial faunas.

Boundaries. The lower boundary of the formation is
placed at the erosional L/R-unconformity capping the
Lønstrup Klint Formation. This has a relief of 0.5-1 m
and is commonly overlain by an up to 0.5 m thick

clast-supported residual gravel bed. In the distal south-
ern part of the Rubjerg Knude Glaciotectonic Com-
plex, the L/R-unconformity is located close to sea lev-
el, and is a convenient structural reference level. It
represents the top level of pre-tectonic sedimentation,
and is hence also a reference surface for the construc-
tion of the balanced cross-section.

The upper boundary is placed at the glaciotectonic

unconformity below the Kattegat Till Formation.

Thickness. The thickness of the formation is about 25

m, but it varies considerably according to local depo-
sitional and erosional development.

Fig. 28. The glaciofluvial Ulstrup beds

deposited above the L/R-unconformity
( L/R-u ) on top of the Lønstrup Klint

Formation. Note the boulder in the
lowermost part of the glaciofluvial

Ulstrup beds indicating the high-energy
(upper flow regime) of the meltwater

streams that deposited the beds (com-
pare with Fig. 20). The divisions on the

measuring pole are 20 cm. Photograph:
May 1998. Ulstrup Section, 5950 m in

cross-section (see Plate 1).

Fig. 29. The glaciofluvial Ulstrup beds
with 'fossil frozen' sand clasts that

indicate ground-frozen conditions in the
source area of the sand clasts; they were

probably derived from the lower part of
the Rubjerg Knude Formation farther

north. Photograph: May 1998.

Distribution. The Rubjerg Knude Formation was mainly
deposited and preserved between the thrust sheets of
the Rubjerg Knude Glaciotectonic Complex. The for -
mation extends towards the south to the area around
Nørre Lyngby where it was mapped as 'Morænesand'
(moraine sand - sandy till) by Jessen (1918, 1931),
and it has not been identified south of Løkken. The
for mation is not recognised in the area north of Løn-
strup, which was mainly covered by ice during depo-
sition of the formation. To the east it can be traced in
wells about 10 km inland, where it pinches out due
to erosion during the transgression of the Younger
Yoldia Sea. The formation probably does not extend
out into the North Sea to the west since it is largely
situated above sea level.

Age. The formation has an age range of 30 000 - 20 000

years B.P. based on ¹⁴C dating of mosses, separated

fr om the organic debris draping the ripple lamination,
and twigs and amber layers (Houmark-Nielsen et al.
1996; Table 2). The mosses investigated were trans-
ported from a carbonate-rich source area, probably
the Cretaceous chalk outcrops near Limfjorden (Fig. 13).

The time span for redepositing plant debris is not re-
garded to exceed hundreds of years, and the age of the

formation was thus interpreted to be closer at 29 000 than

30 000 years B.P. (Fig. 13; Houmark-Nielsen et al. 1996).

Depositional environment. The Rubjerg Knude For -
mation is interpreted to have been deposited on an
outwash plain, which was dissected into smaller pig-
gyback basins during glaciotectonic thrust faulting.
During the development of the piggyback basins,

deposition was controlled by the propagation of the
thrust sheets. North of Lønstrup, a large depression is
regarded as the hole in a hill-and-hole pair from where
the piggyback basins contemporaneous with deposi-
tion of the Rubjerg Knude Formation were dislocated
to the south during the glaciotectonic deformation.

Kattegat Till Formation

History. The Rubjerg Knude Formation is truncated
by a glaciotectonic unconformity and overlain by the
Kattegat Till Formation (Fig. 14). The formation was
erected by Houmark-Nielsen (1987) in the areas sur-
rounding the southern part of the Kattegat and is in-
terpreted to have been deposited during the Weichse-
lian ice advance from Norway. Subsequent studies
have demonstrated that the formation can be identified

over much of the northern part of the Danish Basin
(Fig. 12; Houmark-Nielsen 1999, 2003).

Name. The formation is named after the Kattegat strait
(Fig. 12).

Type section. The type section is at Hundested Klint
(Fig. 12; Houmark-Nielsen 1987).

Reference section. Two reference sections are defined
in the Lønstrup Klint coastal section, namely the top
of the Sandrende locality at point 3700 m in Plate 1
(Figs 19, 30) and the cliff exposure c. 400 m north of
the Mårup church, at point 500 m in Plate 1 (Fig. 31).

Lithology. At the type section, the formation is a grey,
clayey till only a few metres thick; the erratic clasts
are dominantly crystalline rocks of Fennoscandian
provenance and Palaeozoic limestone. Foraminifers and

shell fragments in the matrix have been identified as
having been derived from the Skærumhede Group
(Houmark-Nielsen 1987). In the Rubjerg Knude area,
the till is light beige-brown weathering, dark grey and
sandy with fine- to medium-grained sand in the ma-
trix. Erratic pebbles and cobbles occur scattered in the

matrix, and indicator pebbles of Permian porphyry
from the Oslo region are common (1-5% of the erra-
tics). In the main part of Rubjerg Knude cliff section,
the formation drapes the glaciotectonic complex; over
large areas, it has been subjected to aeolian erosion
that has removed the fine-grained matrix and left the
erratics as a cobble pavement. North of the Mårup
church, the formation comprises a shear till with erra-
tics interlayered in a glaciotectonic breccia dominated
by shear-deformed clayey mud derived from the top
of the Skærumhede Group (Fig. 31).

In the northern part of the Lønstrup Klint cliff sec-

tion (the Ribjerg Section), the Kattegat Till Formation
is absent. The glacial advance, represented elsewhere
by the Kattegat Till Formation, is here recorded only
by a glaciotectonic unconformity and an underlying
glacitectonite characterised by a dense anastomosing
framework of joints penetrating the Skærumhede Group

(Fig. 32).

Boundaries. The lower boundary of the formation is
the glaciotectonic unconformity formed by the shear
at the base of the advancing Norwegian Ice. Below
the unconformity, a glacitectonite 1-2 m thick devel-
oped due to shear deformation of the clay and sand
in the Lønstrup Klint and Rubjerg Knude Formations.

The upper boundary is the subaerial erosional sur-
face above the 1.5 m thick sandy till, commonly reduced

to a 0.25 m thick residual pavement.

Thickness. The formation is up to 1.5 m thick at Ru-
bjerg Knude.

Distribution. The formation has been recognised from
the central and northern part of the west coast of Jyl-
land and Vendsyssel over Djursland and Sjælland to
Hven and Glumslöv in the western part of Skåne,
Sweden (Fig. 12; Houmark-Nielsen 2003).

Age. The age of the Kattegat T ill Formation is bracke-
ted by the Lønstrup Klint Formation beneath (29 000

years B.P.) and the Ribjerg Formation above (26 000

years B.P.) (Fig. 14, Tables 2, 3). The age is estimated
to be 27 500 ± 1000 years B.P. (Houmark-Nielsen 2003).

Depositional environment. The Kattegat Till Forma-
tion is interpreted as a lodgement till. In the area be-
tween Lønstrup and Mårup church, the diamict lithol-
ogy of the upper Skærumhede Group suggests that
deformation of the substratum below the glaciotec-
tonic unconformity was initiated by mud-mobilisation
of water-saturated clay, silt and fine-grained sand.
Material, including erratic clasts from the lodgement
bed along the sole of the ice, dropped into the mud-
mobilised unit. During the advance of the ice, the mud-
mobilised zone became consolidated, and sub-hori-
zontal anastomosing joints formed in the substratum.
The depositional environment therefore changed from
a wet-based glacial advance to an advance over dehy-
drated or even frozen substratum during the deposi-
tion of the Kattegat Till Formation at Rubjerg Knude.

Fig. 30. The c. 1 m thick sandy till on top of the Sandrende Section is referred to the Kattegat Till Formation. The maximum size of

the erratic clasts is 25 cm. The marked planar erosion surface above the till was initially formed by glacial truncation, which
subsequently was exposed to aeolian erosion and finally covered by dunes. Photograph: July 1993.

Ribjerg Formation

new formation

History. The Ribjerg Formation is a new formation
proposed for the c. 25 m thick glaciofluvial sand unit
that crops out between the northern part of the Løn-
strup Klint cliff section and the northern part of the
town of Lønstrup. The unit was indicated in the north-
ernmost c. 2 km of the cross-section of Jessen (1931),
but it was only regarded as part of the main Diluvial-
sand (diluvial sand). Since the formation was depo-
sited in the Late Weichselian between ice advances from

Norway and central Sweden, it might in a glaciodyna-

mic context be correlated with the outwash deposits
of the Tebbestrup Formation in Djursland (Larsen et
al. 1977; Pedersen & Petersen 1997).

Name. The formation is named after the hill of Ribjerg
at Lønstrup.

Type section. The type section is located at the cliff
below the Ribjerg hill, south-west of Lønstrup (Figs
13, 33).

Lithology. The Ribjerg Formation is characterised by
fine- to medium-grained sand showing large-scale

trough and channel cross-stratification (Fig. 33). At

Fig. 31. A pocket of sandy till overlying

a glacitectonite and associated features
of subglacial deformation. The till is

referred to the Kattegat Till Formation.
The locality is situated c. 450 m north of

Mårup Kirke. Photograph: July 1994.

Fig. 32. Planar-parallel and elongated
anastomosing shear joints that are

typical of the glacitectonite at the top of
the Skærumhede Group below the Blå-

unconformity in the Ribjerg Section.
Photograph: July 1994.

the base of the formation, tabular grey mud clasts
(1 x 5-10 cm in cross-section) form a lag deposit in
the fine-grained sand. Lamination outlined by heavy
minerals occurs in the lowermost metre of the forma-
tion and current-ripple lamination with mud chips is
also present (Fig. 33). The lower part of the formation
is characterised by horizontal planar laminated fine-
grained sand interlayered with thin beds (0.1-0.5 cm

thick) of clay-draped current ripples. This facies is
overlain by 0.5 m thick beds of fine- to coarse-grained
trough cross-bedded sand. Troughs or channels, 2-5
m deep and 10-15 m wide, occur in the middle and
upper part of the formation (Fig. 111). In the central
part of the troughs, the fill shows large-scale cross-
stratification. Towards the margin of the troughs, the
beds decrease in thickness and display small-scale

mud

sand

f. m. c.

gr.pb. co.

0 m

Ribjerg Formation

Peat and dune sand

Mid Danish Till Formation

Glaciotectonic-unconformity

Blå-unconformity

Skærumhede Group

X R-990222

X R-990223

X R-990224

Sandy mud

Sand

Dropstones in mud

Gravel

Basal till

Shells

Lamination

Structureless

Mud clasts

Climbing ripples

Trough
cross-bedding

Slump structures

Ball-and-pillow /
convolute bedding

Water-escape pipes
and sand-filled cracks

Tectonite

Clayey mud

Current ripple
cross-lamination

X AAR 4067

Fig. 33. Sedimentological log of the Ribjerg Formation (type section) in the northernmost part of the Ribjerg Section. The formation

was deposited above the Blå-unconformity on top of the Skærumhede Group, and it is overlain by the sandy Mid Danish Till
Formation. The Ribjerg Formation represents glaciofluvial deposition related to a channel-eroded foreland of an advancing glacier.

Note the sand-dykes that are interpreted to have formed by discharge of pore water due to high stream velocity. Samples collected
for optically stimulated luminescence dating are indicated, together with their laboratory numbers (see Table 3).

curr ent

lamination with ripples draped by organic de-

bris. The steeply inclined slopes (up to 30°) of the
trough margins strike 88-94°, indicating an east-west
current direction. Erosional surfaces with slumped beds
and pockets of gravel recur every 1 to 3 m (Fig. 33).
One of the most characteristic features of the forma-
tion is the large number of sand dykes and water-
escape pillars, which are 5-15 cm wide and can be
traced vertically for more than 1.5 m (Fig. 34). The
uppermost 3 m of the formation comprises thick gravel
beds just below the flow till related to the Mid Danish
Till Formation.

Boundaries. The lower boundary of the formation is
defined at the erosional unconformity forming the top
of the Kattegat Till Formation or, where the erosion
level penetrates deeper, the Lønstrup Klint Formation.
In the northern part of the Lønstrup Klint section, the
unconformity on top of the 'Lille Blå' for ms the lower
boundary. The upper boundary is placed at the base
of the flow till that forms the lower part of the Mid
Danish Till Formation (Figs 14, 33).

Thickness. The formation is about 25 m thick.

Distribution. The formation is only recognised in the

Fig. 34. Sand dyke intruded in the

glaciofluvial succession of the Ribjerg
Formation. The sand dykes are interpre-

ted to have formed by pore-water
discharge from the sediment due to high

velocity current flux through the
channels. Photograph: July 1994. Ribjerg

Formation, type section.

vicinity of Lønstrup and towards Vennebjerg to the
east. It is inferred to have been deposited over a larg-
er area of north-western Vendsyssel, which is now
covered by the Vendsyssel Formation (see below).

Age. Three samples were collected from the lower,
middle and upper part of the formation for optically
stimulated luminescence dating (R-990222, R-990223,
R-990224; Table 3); these samples indicate an age of
26 000 - 25 000 years B.P.

Depositional environment. The formation was depo-
sited in fluvial channels cut by westward-flowing melt-
water. The sand dykes and water-escape pillars are
indicative of high pore-water pressure due to rapid
deposition and very fast meltwater flux through the
channels. The outwash deposits are interpreted as a
valley sandur that formed in the depression resulting
from the hole left in the hinterland of the Rubjerg
Knude Glaciotectonic Complex. The source of the melt-
water was the ice margin of the advancing ice from
central Sweden in the Late Weichselian.

Mid Danish Till Formation

History. The Ribjerg Formation of the Lønstrup Klint
section is overlain by a 3 m thick grey-br own till that
is referred to the Mid Danish Till Formation (Hou-
mark-Nielsen 1987, 1999, 2003). The formation was

erected by Houmark-Nielsen (1987) to encompass tills
deposited in the southern and central part of Den-
mark during the Weichselian ice advance from central
Sweden. It is known from the main part of the Danish
Basin east and north of the Main Stationary Line (Fig.
12), and the records of its distribution in the northern
part of Denmark have recently been summarised by
Houmark-Nielsen (1999, 2003) (Figs 1, 12).

Name. The name of the formation reflects the promi-
nent natur e of this surface deposit in central (mid)
Denmark (Fig. 12).

Type section. The type section is at Ristinge Klint on
the island of Langeland (Houmark-Nielsen 1987).

Reference section. A reference section is her ein de-
fined at Ribjerg, SW of Lønstrup (Figs 13, 33).

Lithology. At the type locality, the Mid Danish Till
Formation is a 5-8 m thick unit with at least two boul-
der pavements displaying NE-SW orientated glacial
striation (Sjørring et al . 1982). The formation is a grey
to brown mostly clayey massive till with about 50%
crystalline erratics of Fennoscandian provenance; indi-
cator clasts from the central eastern part of Sweden
(Kinne-diabase) and from Jurassic sedimentary rocks
situated offshore in the Kattegat (Pedersen & Petersen
1997) are abundant (Houmark-Nielsen 1987).

In the reference section at Ribjerg, the formation is

Table 3. Optically stimulated luminescence dates on quartz, Rubjerg Knude

and Nørre Lyngby, Vendsyssel, northern Denmark

Stratigraphic unit

Locality

Lab. ID no.

Material

Age

ka B.P.

Dose+

(Gy)

W.C.++

(%)

Ref.*

Vendsyssel Fm

Nørre Lyngby

R-829202a

Marine clay

± 1

38.9

± 1.3

(1)

Vendsyssel Fm

Nørre Lyngby

R-829203

Marine clay

± 2

46.0

± 0.8

(1)

Ribjerg Fm

Ribjerg

R-990224

Fluvial sand

± 2

45.3

± 0.8

(3)

Ribjerg Fm

Ribjerg

R-990223

Fluvial sand

± 1

52.6

± 1.5

(3)

Ribjerg Fm

Ribjerg

R-990222

Fluvial sand

± 1

53.1

± 1.2

(3)

Lønstrup Klint Fm

Sandrende

R-970204

Fluvial sand

± 2

57.6

± 1.8

(2)

Stortorn Fm

Ribjerg

R-970203

Lacust. sand

± 2

65.0

± 1.8

(2)

+ Equivalent gamma dose.

++ Water content (saturation).

* References: 1: Strickertson & Murray (1999); 2: Houmark-Nielsen (2003); 3: this study.

a yellow-brown weathering, grey-brown, sandy till
comprising a lower stratified unit and an upper mas-
sive unit (Fig. 35). The lower unit comprises laminat-
ed to finely bedded, matrix-supported diamictite with
scattered pebbles. The matrix is fine-grained sand and
the lamination and bedding are slump folded with N-
S-tr ending fold axes and E-dipping axial planes, indi-
cating a westward flow direction. The upper unit is a
massive, structureless matrix-supported diamictite.
Erratic pebbles and cobbles are abundant and the till
has a pronounced a-axis clast fabric dipping at low
angles ( c. 3°) towards the east (100°), indicating a shear
transport direction towards the west.

Boundaries. In the reference section, the lower boun-
dary of the formation is placed at the depositional
conformity on top of the Ribjerg Formation where
planar horizontal gravel beds are overlain by slump-
folded diamictites dominated by debris flow layers.
The upper boundary is an erosional unconformity sep-
arating the diamictites from silt-streaked muds at the
base of the Vendsyssel Formation.

Thickness. The formation reaches a thickness of more
than 10 m at the type section at Ristinge Klint, but it is
only 3 m thick at Ribjerg in the reference section.

Distribution. In the Rubjerg Knude area south of Ri-

Fig. 35. The sandy till that overlies the

Ribjerg Formation is divided into a
lower flow till and an upper lodgement

till. The flow till is characterised by
slump-folded debris flow lamination

indicating flow from east to west. The
till unit is referred to the Mid Danish Till

Formation, which was deposited by the
ice advance from the east, probably

about 24 000 B.P. Photograph: May
1985; notebook for scale. Ribjerg

Formation, type section.

bjerg, where the Ribjerg Formation is absent, it has
not been possible to differentiate occurrences of the
Mid Danish Till Formation from the older Kattegat Till
Formation. However, the distribution is well docu-
mented throughout the Danish Basin east and north
of the Main Stationary Line (Figs 1, 12; Houmark-Niel-
sen 1999, 2003).

Age. The age of the Mid Danish Till Formation is
bracketed by the age of the Ribjerg Formation be-
neath (26 000 years B.P.) and the Vendsyssel Forma-

tion above (16 000 years B.P.) (Fig. 14, Tables 2, 3).

The age is estimated to be 24 000 - 20 000 years B.P.
(Houmark-Nielsen 2003).

Depositional environment. The lower unit is interpret-
ed as a flow till deposited as debris flows from an ice
margin to the east, prior to the ice advance towards
the west. The upper unit is interpreted as a lodge-

ment till deposited at the sole of the ice during the ice
advance from central Sweden towards the Main Sta-
tionary Line situated in the central part of the North
Sea (Fig.12).

Vendsyssel Formation

new formation

History. North and south of Rubjerg Knude, the Mid
Danish Till Formation is overlain by a succession of
glaciomarine heteroliths, which are here defined as
the Vendsyssel Formation. These deposits were map-
ped by Jessen (1899), who related them to deposition
in the Younger Yoldia Sea in Vendsyssel. Jessen (1918)
regarded the various facies of the Vendsyssel Forma-
tion as four stratigraphic units named the Lower Saxi-
cava Sand, the Yoldia Clay (usually prefaced 'Young-

Aeolian sand

Vendsyssel Formation

Lønstrup Klint Formation
glacitectonite

0 m

sand

silt

si.

clay

gr. co.

Tectonite

Climbing ripples

Current ripple
cross-lamination

Sand

Wave ripple lamination

Lamination

Trough
cross-bedding

Gravel

Sandy mud

Clayey mud

Storm sand bed

Bioturbation

Shells

Imbricated mud clasts

Ball-and-pillow
convolute bedding

Fig. 36. Sedimentological log of the Vendsyssel Formation at the type section at Stensnæs. The section is located at point 5120 in the

cross-section (Plate 1); the base of the log is 15 m a.s.l.

er' to distinguish it from the Older Yoldia Clay), the
Upper Saxicava Sand and the Zirphaea Beds.

Name. The formation is named after the region of
Vendsyssel in north Denmark (Figs 12, 13).

Type section. The type section is the coastal cliff sec-
tion at Stensnæs c. 1 km north of Nørre Lyngby in the
central part of the west coast in Vendsyssel (Figs 13, 36).

Reference sections. Two coastal cliff sections, north
and south of Rubjerg Knude, are defined as reference
sections. The locality to the north is the coastal cliff c.
500 m south of Lønstrup, where heteroliths character-
ised by Hiatella burrows crop out (Fig. 37). To the
south, the coastal cliff at Nørre Lyngby (north and
south of the ramp leading down to the beach) prob-

ably gives the thickest accessible outcrop of the for-
mation (Fig. 38). This locality is furthermore close to
the reference well DGU no. 8.137, where the maxi-
mum thickness of the formation is recorded (Lykke-
Andersen 1987).

Lithology. Two main lithologies dominate the forma-
tion: dark bluish-grey, clayey mud in the lower part
and yellowish weathering light grey stratified hetero-
liths in the upper part. At the base of the formation,
coarse-grained sands and gravels overlie the erosion-
al unconformity above the Mid Danish Till Formation
or older deposits (Figs 36-38). The unit referred to as
the Lower Saxicava Sand by Jessen (1918) is less than
2 m thick and is only present locally. Accumulations
of shell debris occur in places. In general, marine clayey

mud forms the lower c. 6 m of the formation resting

Tectonite

Basal till

Aeolian sand

Vendsyssel Formation

Kattegat Till Formation

Lønstrup Klint Formation
glacitectonite

0 m

Sandy mud

Sand

Gravel

Lamination

Wave ripple lamination

Storm sand bed

Bioturbation

Shells

Trough
cross-bedding

Slump structure

Clayey mud

sand

si.

clay

gr.pb. co.

Fig. 37. Sedimentological log of the Vendsyssel Formation at the reference section, situated halfway between Lønstrup and Mårup
Church at point 500 in the cross-section (Plate 1); base of the log is 10 m a.s.l. The slump structure recognised in the lower part of

the section (at about 4 m) is interpreted to have been produced by a grounding iceberg. The abundant shells in the section ar e
Hiatella ar ctica and the bioturbation was due to the infaunal activity of these molluscs (see Fig. 41).

directly on the lower erosional boundary (Figs 36-
38); dropstones, locally to boulder size, occur in the
lower part of the clayey mud unit (Figs 36, 37). The
unit is highly impermeable such that groundwater
wells out at the top of the clayey mud outcrops, often
obscuring the exposures of the basal lithologies. Above
the clayey mud unit, horizontal stratified heteroliths
form a unit 6-12 m thick. In places, the heteroliths
grade into sandy mud characterised by wave ripple
lamination (Fig. 40). Dark grey laminated mud is inter-
bedded with fine-grained sand beds up to 10 cm thick
in which wave ripple lamination is common. At the
reference section, south of Lønstrup, the heteroliths
are intensively bioturbated by vertical trace fossils pro-

duced by Hiatella arctica and the shells are often pre-

served in life position (Fig. 41).

The reference section at Nørre Lyngby is located in

a half-graben structure with the steepest normal fault
(dipping c. 60°S) situated north of the village (Lykke-
Andersen 1992). South of Nørre Lyngby, the erosion-
al unconformity below the Vendsyssel Formation dips
5-8° to the north. The beds above the unconformity
are characterised by sedimentary breccias of mud clasts
probably derived from the Lønstrup Klint Formation
(Fig. 38). In the middle part of the formation, the beds
ar e displaced by synsedimentary faulting (Fig. 38) in-
dicating that the half-graben formed during the depo-
sition of the Vendsyssel Formation.

Aeolian sand

Vendsyssel Formation

Kattegat Till Formation

Lønstrup Klint Formation

sand

silt

si.

clay

gr. co.

0 m

Dropstones in mud

Tectonite

Climbing ripples

Current ripple
cross-lamination

Basal till

Sandy mud

Sand

Lamination

Trough
cross-bedding

Clayey mud

Imbricated mud clasts

Ball-and-pillow /
convolute bedding

Normal fault

Thrust fault

Fig. 38. Sedimentological log of the Vendsyssel Formation at the reference section, situated c. 350 m south of Nørre Lyngby. The

beds rich in imbricated mud clasts reflect the tectonically active nature of the half-graben in which the section is located; the
synsedimentary tectonic activity is further documented by the intraformational normal and thrust faults that occur in the lower half

of the formation at Nørre Lyngby.

In the area north-east of Hirtshals, the clayey mud

is overlain by coastal sands, the so-called Zirphaea Beds

(Jessen 1918), and in the eastern part of Vendsyssel
the uppermost part of the formation comprises coarse-
grained sand and gravel deposited in a large spit sys-
tem (Nielsen et al. 1988).

Fossils. The fossils characteristic of the formation are
the molluscs Portlandia arctica, Hiatella arctica and
Zirphaea crispata .

Boundaries. The lower boundary is the erosional un-
conformity on top of the Mid Danish Till Formation
or older deposits. The upper boundary is the top sur-
face of the landscape upon which locally lie terrestri-
al deposits such as the Allerød peat beds in the Nørre
Lyngby bog (Jessen & Nordmann 1915), the Boreal
peat at Martørv Bakker (Jessen 1931) and recent aeo-
lian sands (Fig. 14).

Thickness. The formation is c. 16 m thick at the out-
crops along the coastal cliff. The formation may reach

Fig. 39. Mud-dominated heteroliths in

the lower Vendsyssel Formation. The
light-coloured silt to very fine-grained

sand beds show grading and wave
ripple cross-lamination. This unit was

formerly referred to as the Younger
Yoldia Clay (Jessen 1918, 1931).

Photograph: September 2004.

Fig. 40. Sand-rich heteroliths in the
upper Vendsyssel Formation showing

wave ripple cross-lamination. This sand-
rich heterolithic unit was for merly

referred to as the Saxicava Sand (Jessen
1918, 1931). Tape divisions in centime-

tres. Photograph: September 2004.

a thickness of up to about 25 m in the central part of
Vendsyssel (see Fig. 125).

Distribution. The flat agricultural land in the Vendsys-
sel area, lying 10-40 m above sea level, defines the
top of the Vendsyssel Formation, and thus can be re-
garded to represent the fossil seabed of the Younger
Yoldia Sea.

Depositional environment. The formation reflects the
establishment of marine conditions in the Vendsyssel
area after the melting back of the Scandinavian Ice
Cap in the Kattegat-Vendsyssel-Skagerrak region. The
palaeoenvironmental development may be described
in terms of six events (Richard 1996): the first event is
represented by the erosional unconformity formed
immediately after deglaciation. The second event was
a rapid transgression with the establishment of a c. 60
m deep arctic marine environment. In the third event,
a high sea-level stand prevailed during deposition of
the clayey mud. Events four to six are stages of forced
regression due to the isostatic uplift in the area, but
with fluctuations due to eustatic sea-level rise.

Age. The age of the Vendsyssel Formation ranges from
17 000 to 14 500 B.P. (Tables 2, 3; Tauber 1966; Krog
& Tauber 1974; Knudsen 1978; Abrahamsen & Read-
man 1980; Aaris-Sørensen & Petersen 1984; Nielsen et
al. 1988; Richard 1996; Houmark-Nielsen 2003).

Fig. 41. At the cliff section north of Mårup Church, the sandy
mud is often highly bioturbated; in places, the shells of the

bivalve Hiatella arctica are found in life position in the escape
trace fossils. Photograph from the middle part of the section in

Fig. 37. Photograph: September 2004.

Geological Survey of Denmark and Greenland Bulletin

Nr. 8 pp 33-59, Structural analysis of the Rubjerg Knude Glaciotectonic Complex, Vendsyssel, northern Denmark

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