Eustatic, tectonic and climatic controls on an early syn-rift mixed-energy delta, Tilje Formation (Early Jurassic, Smørbukk field, offshore mid-Norway) - From Depositional Systems to Sedimentary Successions on the Norwegian Continental Margin - page 350

Table 2. ( Continued )

Sandstone
grain sizes and
description

Mudstone
description

Sedimentary
structures Facies 5 (F5): Heterolithics Thickness (cm) BI and trace fossils Interpretation

5.2.2. (F5.2.2)
Wavy-bedded
combined-
flow hetero-
lithics

Sandstone
0.5 cm to 4 cm;
Mudstone
0.2 cm to 2 cm

Very fine to fine.
Wavy bed-
ding styles.
Occasionally
normal grading
into parallel
laminated
siltstone and
homogeneous
mudstone. Dis-
persed coarse
sand grains at
the base of the
sandy layers

Wavy bedding
styles. Poorly
laminated mud-
stones alternate
in pairs (almost
rhythmically
stratified) with
sandstone.

Parallel lam-
ination,
wave, current
(bipolar) and
small-scale
asymmetric
(round-
crested)
combined-
flow ripples.
Diastasis
cracks (cf.
Cowen &
James, 1992).
Local mantle
and swirl
structures.

BI 1 to 3. Sparse to
moderate. Planolites,
Paleophycus, Skolithos,
Chondrites, Arenicolites
and large Diplocra-
terion, Teichichnus ,
and Cylindrichnus .
BI 3 intervals (with
parallel-laminated mud-
stones and small-scale
wave ripples and, rare,
current ripples), com-
monly alternate with
BI 1 intervals (with
poorly laminated,
normally or inversely
graded mudstones and
current-flow-rippled or
combined-flow-rippled
sandstones).

Low to moderate-strength oscilla-
tory and unidirectional currents.
Deposition might have occurred
by means of hyperpycnal flows
(cf. Bhattacharya & MacEachern,
2009). Alternation of periods
of low river flow or discharge
(BI3, wave ripples, fine grained
sands) with periods of high river
discharge (BI1, current ripples,
fine-coarse sands, fluid- mud
layers).

Facies 5.3
(F5.3)
Mud
dominated
heterolithics
(sand:mud
ratios 10 : 90
to 40 : 60)

5.3.1. (F5.3.1)
Lenticularly
bedded
wave-
dominated
heterolithics

Sandstone
0.5 cm to 3 cm;
Mudstone
0.2 cm to 3 cm

Very fine to
fine. Sand
lenses. Thin
beds showing
aggradation.

Lenticular bed-
ding. Locally
show normal
grading. Thick
weakly lami-
nated and /or
homogeneous
mudstones (fluid
muds) are also
present.

Parallel lami-
nation and
symmetric
(oscillatory)
to round-
crested
ripples.
Small-scale
HCS.

BI 1 to 2. Sparse to
moderate. Small-scale
Planolites, Paleophycus ,
and Chondrites . Vertical
burrows are small (1 cm
to 2 cm long) and consist
mostly of Skolithos and
rare larger Cylindrich-
nus (3 cm to 5 cm long).

Weak oscillatory currents. Depo-
sition of parallel laminated
mudstones by settling from
suspension. Small-scale HCS
formed by sporadic increase of
oscillatory motion due to storms.
Wave generated fluid-mud layers
deposited from resuspended
mud, which could possibly
migrate as hyperpycnal fluid-mud
bodies (cf. Mulder et al ., 2003).

5.3.2. (F5.3.2)
Lenticularly
bedded
current-
dominated
heterolithics

Sandstone
1 cm to 4 cm;
Mudstone
0.5 cm to 3 cm

Very fine.
Locally upper-
medium to
coarse.
Sand lenses.

Lenticular
bedding. No
vertical changes
in grain size.

Ripple cross-
lamination
showing local
bipolarity.
Parallel
lamination.

BI 1 to 3. Moderate to
common. Cylindrichnus ,
Skolithos , Diplocra-
terion , Planolites, Paleo-
phycus , and Chondrites .
Locally, Glossifungites
surfaces.

Weak unidirectional and tidally
influenced currents. Deposition
of parallel laminated biotur-
bated mudstones by settling from
suspension. Sporadic high river
discharges, similar to what is
seen in subfacies 5.2.1 and 5.2.2.