Mesozoic and Cenozoic basin configurations in the North Sea - From Depositional Systems to Sedimentary Successions on the Norwegian Continental Margin - page 418

INTRODUCTION composition, depositional geometry and sequence

stratigraphy.
The scope of this paper is to obtain an improved
understanding of some of the complexities in
the development of the North Sea Basin system, by
studying the geometry of basin infill sequences and
their bounding surfaces. This includes the transi-
tion between late Jurassic to early Cretaceous syn-
rift and post-rift basin stages (Nøttvedt et al ., 1995;
Gabrielsen et al ., 2001), the interplay between basin
subsidence and uplift and erosion of basin margins
and, not least, the denudation of basin hinterlands,
the sediment transport systems and the sediment
deposition in basin realms (e.g. Kyrkjebø et al .,
2000; Gabrielsen et al ., 2001, 2005, 2010a; Faleide
et al ., 2002). For the Cenozoic, the relative influence
of tectonics versus climate on sediment yield from
the hinterland has become an important issue of
discussion (Lindstrom, 1993; Japsen & Chalmers,
2000; Huuse et al ., 2002; Gabrielsen et al ., 2005,
2010a,b; Doré et al ., 2008; Anell et al ., 2009, 2010,
2012; Nielsen et al ., 2009, 2010a,b; Chalmers
et al ., 2010; Goledowski et al ., 2012; Goledowski
et al ., 2014; Rasmussen & Dybkjær, 2014).
Our hypothesis is that the North Sea Basin and
its hinterland areas, being located on the same
continental plate, operated as a coupled structural
system and not as a decoupled system. In a struc-
turally coupled source-to-sink system, crustal pro-
cesses controlling basin subsidence are balanced
or linked with uplifts in adjacent hinterland areas;
in a totally decoupled system, basin and hinter-
land areas behave tectonically independently of
each other. The study focuses on the Late Mesozoic
and Cenozoic depositional systems, particularly
emphasising transitions in basin configuration
resulting from shifting tectono-thermal stages of
development, plate margin tectonics and far field
tectonic influences, as well as climate. Based on
the variations in sequence development, the study
aims also at establishing criteria which can be
used to differentiate various basin configurations.
The main study area is situated between 1 o E to
8 o E and 56 o N to 63 o N (Fig. 1). However, for the dis-
cussion of Cenozoic sediment distribution, the
development of the surrounding areas has also
been taken into account.

The tectono-sedimentological development of the
North Sea Basin system has been extensively
studied during more than 50 years of hydrocarbon
exploration. Despite this, many aspects of the
development of the North Sea Basin remain less
well understood, such as the structural relation-
ship between source-and-sink, or hinterland and
basin, basin subsidence and inversion mecha-
nisms, the interlinked effects of tectonics and
climate in sediment production and deposition
and the eustatic control versus tectonic control on
creation and destruction of accommodation space.
The North Sea Basin developed as a continental
basin in post-Caledonian (Devonian) time, becom-
ing a lowland region of north-west Europe,
underlain by the European continental plate,
which included Caledonian rocks accreted to the
Precambrian crust of Europe. Since the major
marine transgression in the Early Jurassic (e.g.
Evans et al ., 2003), the North Sea Basin system
has been, dominantly, a marine epicontinental
basin. Sub-basins developed during late Palaeozoic
and Mesozoic time through several events of crus-
tal extension and rifting, fault block rotation and
basin inversion and, in the Cenozoic, by fault
tectonics, halokinesis and differential subsidence,
driven by various tectonic mechanisms, as well as
differential sediment compaction. Sediment com-
position, grain size and routing were controlled
by bedrock, relief, slope gradient and orientation,
development of drainage systems and climate in
the hinterlands of the North Sea Basin. Since the
early Jurassic, potential sediment source areas to
the North Sea Basin system were located to the
west, east and south. These source areas were
locally supplemented by intermittent intrabasinal
highs formed by remnant flanks of rotated fault
blocks and basin inversions (Gabrielsen et al .,
2001; Kyrkjebø et al ., 2001). The marine basin
opened to the Borealic Basin in the north and was
linked by several shallow-marine seaways to the
proto-Tethys and Tethys in the south (e.g. Ziegler,
1982, 1990; Evans et al ., 2003; Anell et al ., 2012).
The bulk sediment infill was controlled by the
evolution through time of the ratio between rate of
creation of accommodation space (A) and rate of
sediment influx (S). The A/S ratio varied in time
and space as a function of intrabasinal and hinter-
land tectonics, rate and geometry of basin subsid-
ence, climate and eustasy. The complex interplay
of all of these factors is reflected in the basin by
sediment thickness, textural and mineralogical

Database and methodology

The present seismic interpretation utilised
60,000 km of long-offset regional 2D reflection
seismic data (NSR survey), acquired by Fugro
Multi Client Services and TGS Nopec between