Depositional dynamics and sequence development in a tidally influenced marginal marine basin: Early Jurassic Neill Klinter Group, Jameson Land Basin, East Greenland - From Depositional Systems to Sedimentary Successions on the Norwegian Continental Margin - page 331

The three incised valley systems were formed
during basinward extension of major river sys-
tems during events of major fall in relative sea-
level. These rivers originated in hinterland areas
on present-day Liverpool Land or a larger ancient
land area further to the east that may have been
the Jan Mayen microcontinent (Figs 15 and 16) (cf.
Mjelde et al ., 2008; Breivik et al ., 2012). The
width:depth ratio of the incised valleys and their
position and orientation, may have played an
important role in creating high-energy tidal sys-
tems within the valleys. The estuaries which filled
these incised valleys received great amounts of
clastic detritus to bay-head deltas and to sediment
convergent areas in the middle part of the estuar-
ies. Part of this fluvial sediment input may have
bypassed into the shallow marine realm, from
where sediments may have been transported back
during the infilling of the estuaries. All the estuary
infill deposits are considered as tide-influenced
to tide-dominated. The predominance of tidal
currents during the infill of the estuaries explains
the absence of distinct fine-grained central basin
deposits and/or wave-dominated barrier deposits.
However, the few examples of associated wave-
dominated shoreface deposits indicate co-existence
of strong tidal and wave energy environments in the
outer parts of these estuaries (cf. Dalrymple et al .
2012; Tessier, 2012). The increase of wave-formed
structures relative to tidal features in the uppermost
part of the incised valley infill successions was
probably the result of widening of the marine
embayments by rising sea-level, exposing them to
increasing wave activity.

sequence 1, with MFS1 located close to the lower
transgressive boundary, indicates a rapid rise in
relative sea-level and establishment of maximum
water depth (accommodation space) shortly after
initial transgression. The aggradational pattern of
the regressive systems tract RST 1 (Figs 7 and 14)
reveals a close balance between creation of accom-
modation space and rate of sediment supply. This
helps explain why the Neill Klinter Group lacks
basin-scale clinoform geometry with shoreface depos-
its that could define distinct shoreline trajectories.
The relatively low relief of the lowermost
unconformity surface SU1/TS3 may imply mod-
erate incision, or that the cross-section occupies a
rather distal position in the incised valley (Fig. 7).
The higher reliefs of the other incised valleys,
defined by the surfaces SU2/TS5 and SU3/TS6,
indicate that these two sections represent rather
proximal positions of the incised valleys. The
considerable lateral and vertical variation in par-
alic subenvironments within the T-R sequences
3 to 6 (Fig. 7) is interpreted to have been formed
along coastlines with fluctuating geomorphology.
The ratio between creation of accommodation
space and rate of sediment supply varied signifi-
cantly along the coast, as did the dominating
energy system, giving rise to a dynamic variation
in the sedimentary environments (updip and
downdip, laterally along the coastline and strati-
graphically); a common feature in tidally influ-
enced paralic settings (Dalrymple & Choi, 2007;
Martinius & Van den Berg, 2011). However, an
overall aggradational to retrogradational deposi-
tional setting prevailed. The distance of sedimen-
tary transport was relatively short from the
surrounding cratonic basement areas that yielded
large influxes of clastic material to the Jameson
Land Basin. This is interpreted to be related to
the warm and humid climate that in the Early
Jurassic succeeded the arid to semi-arid climate
of the Triassic in the NE Atlantic region (Frostick
et al ., 1992; Clemmensen et al ., 1998; Müller
et al ., 2005; Ruhl & Kürschner, 2011). The warm
and humid climate in the Early Triassic-earliest
Jurassic gave rise to an increase in chemical
weathering. This is reflected by the dominantly
quartz-arenitic composition of the sandstones in
the Neill Klinter Group and by the abundance of
quartz and quartzite pebbles versus granitic peb-
bles in conglomerates. The formation of glauco-
nite, iron-rich ooids and early-diagenetic chlorite
in shallow-marine paralic environments also
points to a high delivery of Fe 2+ ions from land, as

Sequence development in the Neill
Klinter Group

The six T-R sequences in the Neill Klinter Group are
inferred to be basin-wide. They represent an overall
rise in relative sea-level from lowstand in the conti-
nental Kap Stewart Group to highstand in the basin-
wide offshore marine Sortehat Formation. The T-R
sequences 1 and 2 were formed during the initial
flooding stage of the basin and were terminated by
a fall in relative sea-level and the establishment of
the first SU and incised valley system. Lateral dis-
tribution of depositional environments (Fig. 7)
within T-R sequences 1 and 2 was controlled
mainly by the intrabasinal distribution of fluvial-
dominated, tidal-dominated and wave-dominated
energy systems. The marked asymmetry of the
transgressive systems tract TST1 in the T-R