Mesozoic and Cenozoic basin configurations in the North Sea - From Depositional Systems to Sedimentary Successions on the Norwegian Continental Margin - page 443

which suggested an eastern source for sediments
which infilled the depocentre offshore Sognefjord.
As this occurred simultaneously with volcanic
activity in the North Atlantic Igneous Province,
the uplift and subsidence observed in Late
Palaeocene and Eocene was probably linked to a
common set of processes, which led to rifting and
later break-up of the NE Atlantic.
Because the Eocene depocentre within the
Norwegian-Danish Basin contains sandstone
(Strass, 1982), this accommodation space was
probably situated close to a source area. Erosional
channels are recorded, cut into the top strata of the
Chalk Group at the Sorgenfrei Tornquist Zone and
the Ringkøbing Fyn High (Huuse, 1999), reflecting
that these structures became inverted, probably
due to intraplate stresses related to Alpine com-
pression in southern Europe. These or similar
channels may have acted as pathways for silici-
clastic material from the Fennoscandian Shield.

processes in the European crustal plate. This is
further discussed below.

Basin development and sediment supply

A major shift in sediment provenance occurred at
the onset of the Oligocene sequence CSS-3, as indi-
cated by the W-SW progradation in the eastern
North Sea area at that time (Fig. 9). The main depo-
centres of Oligocene age in the Norwegian-Danish
Basin (Fig. 11) are here suggested to have been
sourced from the NNE (Fig. 15D). The presence of
sandstones in the Lower Oligocene (Danielsen
et al ., 1997) supports the hypothesis of shoreline
progradation towards a southern direction in
CSS-3 time, becoming situated close to the source
area. This is in accordance with Michelsen et al .
(1995) and Danielsen et al . (1997), who found that
the Oligocene sequences consist of sandstone
bodies representing near-shore marine sediments
deposited during a S-SW progradation of the
shoreline. The abrupt switch from a mainly west-
ern source to a dominant eastern/north-eastern
source in Early Oligocene is a strong indication
that renewed uplift and exposure of landmasses
occurred in earliest Oligocene time.
A sudden decrease in ocean temperature in
early Late Oligocene (Molnar & England, 1990;
Sliwinska et al ., 2010) is used to explain the sud-
den input of erosional material in the eastern
North Sea (Goledowski et al ., 2012) and hence,
that changing depositional patterns are controlled
by a climatic change. However, temperature drops
cannot explain the rapid creation of accommoda-
tion space in the eastern North Sea, which fol-
lowed a period of truncation at the Eocene to
Oligocene boundary (Fig. 2). Also, truncation of
Eocene strata and the absence in some places of
Lower Oligocene strata on the Patchbank Ridge
(Fig. 12) indicates that Early Oligocene uplift
occurred within the basin, in addition to affecting
extensive areas of southern Norway. Therefore,
although climatic changes probably contributed
to increased sediment production in mainland
Norway in Oligocene time (e.g. Huuse et al ., 2001;
Huuse, 2002; Nielsen et al ., 2009), differential tec-
tonic uplift is, nevertheless, also probably exposed
landmasses for increased erosion due to rejuvena-
tion of the relief. This is also supported by obser-
vations of Upper Oligocene (CSS-4) NW-SE
trending normal faults, which reflect NE-SW grav-
itationally driven extension on the Horda Platform
(Clausen et al ., 1999). These faults were active

Basin configuration 4

At the Eocene-Oligocene boundary, vast quantities
of sediment were transported into the eastern North
Sea area, with S-SW progradation, indicating the
existence of a new source area in southern Norway.
This depositional pattern continued throughout
the Neogene. As glacio-isostatic rebound in Plio-
Pleistocene times (Riis & Fjeldskaar, 1992) cannot
explain the Neogene tilting of the sedimentary lay-
ers itself (Riis, 1996), an additional vertical uplift of
Scandinavia has been suggested as an explanation
(Jordt et al ., 1995, 2000; Michelsen, 1995; Rohrman
et al ., 1995; Martinsen et al ., 1999; Japsen &
Chalmers, 2000; Japsen et al ., 2002, 2007; Faleide
et al ., 2002; Anell et al ., 2009, 2010, 2012; Chalmers
et al ., 2010; Gabrielsen et al ., 2010a, b). However,
increased sediment input in late Palaeogene and
Neogene times was also controlled by climate
changes and eustasy (Huuse, 2002; Nielsen et al .,
2009; Goledowski et al ., 2012).
The observed change in infill pattern and the
diachronous creation of accommodation space
in the study area, concurrently with uplift of
southern Norway, is here suggested to reflect a
new basin configuration as compared to basin
configuration 3. We therefore propose that this
change in the main direction of sediment trans-
port, contemporaneous with changes in geome-
try in the North Sea Basin system, indicates that
hinterland and basinal area were structurally
coupled by some sets of common tectonic