Applying accommodation versus sediment supply ratio concepts to stratigraphic analysis and zonation of a fluvial reservoir - From Depositional Systems to Sedimentary Successions on the Norwegian Continental Margin - page 110

(A) Stratigraphic scale

(net accommodation 'window')

(B) Avulsion scale - autogenic response

(real time accommodation 'window')

4

2

3

2

1

1

Fig. 6. Illustration of the principle of superposition of scales of A/S sequences. (A) Based on 1) the definition of real-time
accommodation and net accommodation and their use in stratigraphic analysis (see text) and 2) avulsion data presented by
Stouthamer & Berendsen (2007) it is suggested that the highest resolution related to the shortest time scale that can be used
in the A/S analysis of fluvial deposits (level 2 in the figure) is approximately 10 4 yr. These authors suggested that individual
avulsion deposits may or may not be the result of autocyclic processes and are initially deposited in the real-time accommo-
dation window. Consequently, these deposits cannot be used for rock record. The orange bar indicates the stratigraphic
column. (B) Avulsion scale. This cycle scale can be autocyclic controlled and can therefore not be used for reservoir zonation
purposes. Numbers schematically refer to individual avulsion events.

(A)

± 1 km

Immature paleosols
Geomorphic base level

(B)

± 15 km

Unconformity

Mature paleosols

(C)

± 50 km

Semiregional unconformity

Mature paleosols

Fig. 7. Principles of correlation in fluvial successions. (A) Individual channel deposits cannot be used for stratigraphic
correlation purposes (see text for explanation). (B), (C) The most mature palaeosols on the floodplain correlate with the
unconformable basal surfaces of alluvial valleys to form stratigraphic turn-around locations from decreasing to increasing
accumulation space and can be used for subsurface correlation purposes.