Geoscience Reference
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1) Shoreline and centroid locations
2) Number of channels along each cross-section
320 ka
0
1
2
3
4
5
10
20
30
40
300
256 ka
250
248 ka
Shoreline
Centroid
Small feeder vallely
200
See Fig. 3B-5
Fluvial plain
162 ka
150
154 ka
Small delta
Deep incised valley
See Fig. 3A-4
132 ka
Centroid
Shoreline
See Fig. 3A-3
Widespread fluvial plain
100
78 ka
50
26 ka
Large deltas
Small incised vallely
See Fig. 3A-2
0
-50
-100
-150
-200
-250
0
10
20
30
40
50
Sea-level (m)
Distance (km)
10
20
30
40
50
0
Shoreline and Centroid (km)
Sea-level
Shelf break location
Centroid location
Markers
Fig. 4. (1) Comparison of sea-level variations and migration of the shoreline and centroid of the passive margin, (2) analysis
of the number of channel at each age along each strike section of the numerical model.
incision, filling and avulsion. On the contrary, on
the east side of the basin, subsidence was higher
than the eustatic sea-level fall. Channel fed
downslope large deltas. This normal regression was
characterised by a broad and composite erosional
surface westward and aggradation and progradation
of the margin eastward. Shoreline and centroid
moved eastward more or less at the same rate
(Fig. 4). This regression was followed by a retrogra-
dation then aggradation of the depositional systems,
characterised by a widespread fluvial plain (78 ka to
144 ka, Figs  3A-3 and Fig.  4). Fluvial onlaps onto
flat-lying fluvial strata could be observed both along
dip section (Fig. 5-1) and on the statistical analysis
of centroid and shoreline location. During this
regression, the centroid was moving back towards
the west side of the basin and was around 20 km to
30 km upstream of the shoreline (Fig. 4).
During the fast sea-level cycle (Fig. 3A-4, 132 ka
to 154 ka and Fig. 4), the eustatic sea-level fall was
now faster than the subsidence rate everywhere. It
was so fast westward that the feeder channel was
forced to incise and had to stay in place. A deep
incised-valley was formed (Figs  4 and 5), which
fed  downslope a small lobate shelf-edge delta
(Fig. 3A-4). This accretionary forced regression was
characterised by a major subaerial unconformity
eastward, truncated toplaps westward and steep
marine foresets which downlap the previous maxi-
mum flooding surface (Fig. 5-2). The centroid was
now moving very fast and was nearly at 50 km
downstream the shoreline (Fig.  4). This forced
regression was followed by a rapid flooding and
transgression of depositional systems (Fig.  3B-5),
characterised by the infill of the deep incised valley
by backstepping units and onlaps onto the subaerial
exposure surface (Fig. 5-3). During the second stage
(200 ka to 320 ka), with superimposed slow and fast
sea-level cycles, the same evolution of the deposi-
tional systems was recorded, with deep incision of
fluvial valleys during sea-level fall (Fig. 3B-6) and
filling during sea-level rise (Figs 3B-7 and 8).
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