Modelling Coastline Change of the Darss-Zingst Peninsula with Sedsim - The Baltic Sea Basin - page 288

Table 14.1 Translation scheme of the simplified sedimentological surface model (Fig. 14.4 ) toa
Sedsim-compatible sediment composition

Coarse (%) Medium (%) Fine (%) Silt (%) Porosity (%)

Ø: 0.75 mm Ø: 0.375 mm Ø: 0.15 mm Ø: 0.03 mm Ø: 0.75 mm

: 2,650 kg/m 3 : 2,650 kg/m 3 : 2,650 kg/m 3 : 2,550 kg/m 3 : 2,650 kg/m 3 ρ ρ ρ ρ ρ

I 8 28 54 10 40

II 0 0 0 100 80

III 12 22 35 31 20

ρ

Ø: grain size diameter, :density

the outcropping sediments was set to a homogeneous value of 10 m, parameterized
in Sedsim by the DEPOSIT module.
Considering the borders of the study area, additional sediment input can be
neglected. To the south, the mainland forms a natural barrier, while to the north
the open sea with larger water depths serves as a discharge area. In the west the area
is bordered by the river Warnow. This river's mouth is very important for sea traf-
fic and constantly dredged, therefore, preventing additional sediment input from the
west. Because the longshore transport proceeds from west to east, the area bordering
to the east is excluded as a sediment source, too.

14.4.3 Vertical Movement of the Earth's Crust

The Darss-Zingst region is located on the southern border of Scandinavia, which
is lifting up because of glacioisostatic adjustment (Björck 1995 ) . The maximum
magnitude of this uplift is about 9 mm/year in the Gulf of Bothnia, while there
are negative values in a surrounding subsiding area (Harff et al. 2001 , Rosentau
et al. 2007 ) . Although these maps are considered to show the vertical movement
of the earth's crust, it has to be noted that they are constructed from gauge mea-
surements and include the eustatic signal. Only a removal of this parameter reveals
the true pattern of vertical movement of the earth's crust (Harff and Meyer 2007 ) ,
which is required for a Sedsim input parameterization. For the western Baltic Sea,
a eustatic sea level rise of approximately 1.0 mm/year during the last century
is postulated by Hupfer et al. ( 2003 ) . This value was used by Harff and Meyer
( 2007 ) for the calculation of a revised model of the vertical movement of earth's
crust.
On a first glance, these movements are rather small in the study area (Fig. 14.5 ) .
Largest uplift for the peninsula is calculated with 0.4 mm/year in the Zingst region,
whereas in the southwest parts the crust is actually sinking. On a scale of a mil-
lennium this will sum up to 0.4 m uplift, respectively, 0.2 m subsidence. These are
magnitudes that have to be taken into account when modelling coastlines, and the
module TECTONICS was parameterized using these data.