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 384

(A)

(B)

Horizontal scale
~ 10 km

Legend

Mouth bars

Smørbukk field perimeter

Interpreted sea floor contours

Land/tidal creeks

Interpreted current directions

Relative water depth

shallow deep

Fig. 24. Schematic block diagrams showing the interpreted palaeogeographic reconstructions for the Tilje Formation in the
Smørbukk field (dotted outline), relative to the Smørbukk and Trestakk normal faults, during the lower-middle Tilje (T1.2
to T3.1) and B) the middle-upper Tilje (T3.2 to T4) times.

(Martinius et al ., 2001), which coincidentally,
occurred during a second-order eustatic sea-level
drop in the mid-upper Pliensbachian (Hallam, 1988;
Surlyk, 1990; Hallam, 1999). This palaeogeographic
change could be caused by two possible processes:
1) river avulsion or 2) the repositioning of the river
system by tectonic activity. However, the constant
location of the sediment-entry point over a very long
period of the early Tilje depositional time (during

sequence 2), as indicated by the constant fining
trends (Figs 20 to 21) and the absence of compensa-
tion-style stratigraphic architectures, suggests that
the main fluvial system was probably confined by
structural/topographic controls towards the N-NW.
Therefore, the abrupt switch during the formation of
SB3 implies that a major tectonic movement
deflected the river and locked it into a new axially
oriented (N-NE to S-SE) course (cf. Bosence, 1998).