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static angle of repose, then all sediments above
the safety plane move downslope until the new
depositional slope is lower than the dynamic
slope angle. Finally, compaction of sediments is
computed using burial depth-porosity laws and
elastic flexure due to water, while sediment
loading is calculated assuming a 3D elastic litho-
sphere. The solution of this numerical model is
obtained using an implicit finite volume scheme
(Eymard
et al
., 2004; Gervais, 2004; Gervais &
Masson, 2004).
system and often referred to as 'Jurassic Tank'
(Paola, 2000; Paola
et al
., 2001). The XES facility
is a large experimental basin (3 m x 6 m) where
scaled down experiments on natural systems
can be tested. The XES 02 experiment was
designed to examine the effects of slow and
rapid base-level cycles on the stratigraphy of a
passive margin. It is a perfect candidate to
explore and analyse the behaviour of sediment
transport at a regional scale and thus to test the
capacity of our numerical model to reproduce
important morphologic characteristics such as
erosional unconformities, valley incisions and
preservation of stratigraphy. The parameters of
the XES 02 experiment were upscaled to con-
struct a theoretical basin-scale passive margin
using simple similarities rules.
The characteristics of height, time, slope and
sediment concentration of the XES02 experiments
are respectively 110 mm, 20 h, 35° and 30 g l
−1
(Table 1). Scaling parameters were defined to pro-
duce a theoretical passive margin setting looking like
a real work example. XES02 base level cycles
(period ~ 20 hours, amplitude = 110 mm) were sup-
posed to be similar to extreme glacial sea-level cycles
(period ~ 20 ka, amplitude = 110 m). The time ratio
was around 10
9
and the height ratio is 10
3
. The angle
of the XES 02 slope is around 35° (or 700 m km
−1
),
whilst classical continental margin slope is around a
few degrees (e.g. Adams
et al
., 1998; Adams &
Schlager, 2000; O'Grady
et al
., 2000; Kertznus &
Kneller, 2009; Covault
et al
., 2011). The slope ratio
was thus defined as equal to 0.1, which led to a mar-
gin slope equal to 4° and a length ratio equal to 10
4
.
The length and height ratios defined the upscaled
sediment volume and supply, around 1820 km
3
My
−1
.
METHODOLOGY
The main objective of this paper is to present
and illustrate the use of non-linear diffusion
equations to simulate transport of sediment at a
regional scale. Direct numerical simulation of a
full sedimentary system remains largely empiri-
cal (Paola
et al
., 2009), in particular at a regional
scale, as in Dionisos. The study of a sedimentary
basin where all controlling parameters, bound-
ary conditions and sedimentary architecture are
known would be the best natural experiment to
validate transport equations. Due to the lack of
fully documented basin systems, stratigraphic
flume experiments are candidates for such a
study (Postma
et al
., 2008).
Passive margin model
A theoretical passive margin was defined from
the well-documented XES02 flume experiment
(Strong & Paola, 2008; Martin
et al
., 2009, 2010),
conducted in the Experimental EarthScape (XES)
Table 1.
Key parameters used in the XES 02 experiment (Strong & Paola, 2008); upscaled parameters
used in Dionisos and scaling ratios.
XES 02 experiment
Dionisos model
Scaling ratio
Duration of the short-term
eustatic cycle
20 h
20 ka
t = 3.2 10
8
Time interval
320 h
320 ka
t = 3.2 10
8
Amplitude of sea-level cycles
110 mm
110 m
h = 10
3
Margin slope
35° (700 m km
−1
)
4° (70 m km
−1
)
h/l = 0.1
Fluvial slope
2° (35 m km
−1
)
0.2° (3.5 m km
−1
)
h/l = 0.1
Basin length
6 m
60 km
l = 10
4
Basin area
6 × 3 = 18 m
2
1800 km
2
l
2
= 10
8
Subsidence
3.71 mm h
−1
3710 m My
−1
h/t = 3.2 10
−6
Sediment supply
0.303 l min
−1
1820 km
3
My
−1
h.l
2
/t = 320
Sediment concentration
30 g l
−1
0.6 g l
−1
c = 0.02
Water supply
25 l min
−1
240 m
3
s
−1
h.l
2
/c.t = 16,000
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