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 346

Table 1. Upper Åre and Tilje formations lithofacies identiied on the basis of their heterolithic nature, grain size, bedding style, sedimentary structures, thickness, and
bioturbation style (See Table 2 for heterolithic Facies classiication).

Sedimentary
Structures Facies Subfacies Grain size/ description Thickness BI and trace fossils Interpretation

Facies 1 (F1):
Graded and
non-graded
conglom-
erate

(i) Normally graded
oligomictic quartz-
pebble orthocon-
glomerate.
(ii) Normally graded
oligomictic quartz-
pebble paracon-
glomerate.
(iii) Inversely graded
polymictic paracon-
glomerate.
(iv) Non-graded oligo-
mictic paracon-
glomerate.

Round to sub-rounded
quartz pebbles (3 cm
to 5 cm) and granules.
Siderite and intraforma-
tional mudstone clasts
are present. By volume
the clast fraction is bet-
ween 60% to 75% and
the matrix fraction is
between 25% to 40%.
Erosive basal contacts.

Beds 10 cm
to 30 cm
thick,
although
amal-
gamated
conglom-
erate beds
can be up
to 40 cm
thick.

Normal and
inverse grad-
ing

BI 0. Trace fossils absent. High-energy flows.

Normally graded beds deposited
by dilute turbulent flows or by
waning flows.
Inversely graded beds deposited
by more concentrated flows in
which dispersive pressure oper-
ated, or by waxing flows. Poorly
sorted beds with a high matrix
percentage suggest highly con-
centrated sediment flows.

Facies 2 (F2):
Cross-
bedded
sandstone

(i) Poorly sorted,
coarse-to medium-
grained, cross-bed-
ded sandstones.
(ii) Moderately sorted,
medium-grained to
fine-grained, cross-
bedded sandstones.
(iii) Poorly sorted,
medium-grained to
fine-grained, low-
angle cross-bedded
sandstones with
angular bioclastic
calcite grains.

Sand : mud ratio bet-
ween 100 : 0 and 90 : 10.
Coarse-grained to
medium-grained or
fine-grained, poorly to
moderately sorted grey,
to dark brown sandstone.
Mica-rich intervals.
Thick homogeneous
mudstone layers (<3 cm)
and mudstone laminae
(showing pairs and/or
thick-thin alternations)
in bottomsets of the cross
beds. Sharp and erosive
basal contacts.

Fining-
upward
cosets up
to 2.5 m
thick.

Large, low-angle
to high-
angle cross-
stratification.
Progressively
steeper
laminae incli-
nations toward
bed tops.
Local herring-
bone cross-
stratification.

BI 0 to 1. Absent to sparse.
Low-diversity. Large-scale
Diplocraterion , and
Skolithos . Rare Teich-
ichnus and Bergaueria .

River and tidally influenced,
moderate to strong currents.
Trace-fossil assemblage suggests
brackish-water conditions at
times.
Thick homogeneous mud layers
suggest deposition from high-
concentration near-bed suspen-
sions (fluid muds). Local poorly
sorted low-angle cross-bedded
sandstones product of wave or
current energy.

Facies 3 (F3):
Current
ripple
cross-
laminated
sandstone

No subfacies. Sand : mud ratio between

100 : 0 and 90 : 10. Fine-
grained to very fine-
grained, poorly to mod-
erately sorted, light grey
to light brown sandstone.
Alternation with very
thin mudstone laminae.
Sharp and erosive basal
contacts.

Individual
set thick-
nesses vary
between
2 cm and
5 cm. Beds
up to 40 cm
thick.

Small-scale, low-
angle to high-
angle, bipolar
ripple cross-
lamination.
Local climbing
ripples.

BI 1. Sparse. Low-diversi-
ty. Small Skolithos and
rare Planolites

Tidally-influenced slow to
moderate currents. The local
presence of climbing ripples
indicates rapid deposition from
decelerating flows, probably
associated with river floods.