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complex also contains a series of stacked fan sys-
tems separated by soft-sediment deformed units
reflecting repeated intervals of basin margin
deformation and slope structuring. Basin-margin
structuring also has been argued as a fundamen-
tal controlling factor on the repeated advances
and retreats of sandy fans on the immature pas-
sive margin off western Africa (Hadler-Jacobsen
et al . 2007) and for rift margin fans in the north-
ern North Sea and northern Norwegian Sea
(Ravnås et al . 2000).
The recognition of high-order architectural
elements that represent specific depositional ele-
ments was previously speculative at best, but can
now be better defined using the characteristics
and significance of the various mudstone and
claystone types. Importantly, this permits 1) reser-
voir architectures to better identified and more
reliably delineated in the subsurface and 2) for
architectural elements ranging from the bed scale
through lobe storeys and lobe complexes to
turbidite systems, to be organised hierarchically,
similar to the approach applied to analogue out-
crop turbidite systems (e.g. Mutti & Normark,
1987; Prélat et al ., 2009).
The inferred deltaic supply poses challenges
for the postulated duration of the Ormen Lange
fan systems. A ready source of sediment deliv-
ered to the shelf edge favours more rapid fan
accumulation, yet it is well established that the
fans span the Maastrichtian to Danian time. A
plausible explanation is that significant intervals
of time are recorded in the mudstone interval
separating the two fan units, the drapes separat-
ing lobe storey set/-complexes and those separat-
ing the various lobe storeys within the fans. In
turn, this implies that individual channel storeys
to lobe storeys represent distinct depositional
events, each producing a fundamental strati-
graphic element, which in turn forms the basic
building blocks for the depositional evolution of
the sandy fan and its resultant sedimentary
architectures.
The low sediment supply to the Møre Basin,
especially in the Danian, is at odds with that of
the Vøring Basin to the north (e.g. Kjennerud &
Vergara, 2005). In contrast to the Vøring Basin,
the Møre Basin was bordered by relatively
low-relief hinterland of limited lateral extent (cf.
Sømme et  al ., 2009), formed partly by uplift of
the former northern North Sea shelfal chalk sea
(e.g. Brekke & Olaussen, 2007). The relatively
low sediment supply to the Møre Basin during
the Maastrichtian and Danian is thus attributed
to the limited sediment yield potential from this
newly formed and tectonically rejuvenated rift-
shoulder hinterland. As such, the Maastrichtian
and Danian fan systems sourced from the south-
ern Norway uplands, such as the Springar and
Egga fans along the Møre Margin and the Danian
to Selandian Siri fan system in the Norwegian-
Danish Basin (Hamberg et  al ., 2005; Svendsen
et al ., 2010), appear to represent a special case of
fan development; sediment starved sandy fans
with delivery of sand from a relatively mud-poor
delivery system into an otherwise sediment
starved basin.
The prevalence of slope-parallel currents along
the Møre Margin resulted in alternating domains
of inhibited mud deposition, such as across the
Egga fan to the south and the development of
sandy 'mud pits' in areas where the slope currents
were sufficiently weak to permit net sediment
accumulation (such as the northern part of the
Ormen Lange subbasin).
CONCLUSIONS
1 The reservoirs of the giant Ormen Lange field,
located off the Møre coast, are deep-marine tur-
bidites within the Upper Maastrichtian Springar
Formation and the Danian Egga sandstone unit.
The Springar Formation represents the outer
parts of a sandy fan system whereas the Egga
sandstone unit is interpreted in terms of middle
to inner parts of a similar sandy fan system.
2 The two fan systems were deposited on terraces
or subtle minibasins on the lower slope. The two
fan systems were sourced from an uplifted and
tectonically rejuvenated hinterland, formed in
response to Late Cretaceous to Early Palaeogene
extension in the Norwegian-Greenland Sea rift.
3 The Springar and Egga turbidite systems evolved
through a 'fill-spill' mechanism, with slope ter-
races and minibasins connected via a variety of
channelised corridors.
4 Within an individual mini-basin or slope
terrace, an early phase of 'infilling' or smooth-
ing of inherited topography appears to have
been followed by a more organised backfill-
ing or upslope onlapping combined with
forestepping or outbuilding of the sandy fan
across the individual terraces or infilled
mini-basin. Progradation of the fan resulted
in basinward translation of the inner fan
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