Geoscience Reference
In-Depth Information
total of five axial isolines of post-glacial, wave-undercut cliffs were identified: two
dated to the Yoldia Sea (58-45 and 52-40 m), one assigned to the Ancylus lake
(38 m), and two dated to the Littorina Sea (29 and 21 m).
In the southern Baltic the Littorina transgression leads to inundations of the
coastal lowlands. Due to the sheltered position in the Gulf of Gdansk, the terrestrial
ecosystems have been preserved, forming a unique inventory of palaeo-ecological
proxies. Uscinowicz et al. have investigated the nature of the plant communities, and
also tree stumps position in relation to the palaeo-sea level. Tree stumps occurring
in situ on the sea floor along with peat deposits are the most reliable indicators of
sea level changes. The characteristic forest composition of that time was the broad
deciduous forest with oak (
Quercus
), elm (
Ulmus
), and lime (
Tilia
). The climate
was characterized by good thermal and moisture conditions, which is confirmed by
the presence of pollen grains of mistletoe (
Viscum
) and ivy (
Hedera
). The obtained
data from the time of accumulation of the investigated sediments indicate that the
sea level at that time was about 19-20 m lower than is at present. At open coasts,
a slowly rising sea level in the Late Holocene, together with storm-induced wave
action, has lead to amplified cliff erosion. In the southern and south-eastern low-
lands, the accumulation of eroded sediments leads to the formation of sandy barriers
and spits. Lampe et al. have studied the factors influencing the formation of sandy
spits, with the Darss-Zingst Peninsula as an example. These are among others, the
eustatic sea level rise, the rates of land uplift and subsidence, the inclination of the
pre-transgressional bottom relief, and the amount and type of supplied sediments.
In a final synopsis the authors assess the interplay of all factors, explaining the
distribution, volume, and stability of the barriers along the German Baltic coast.
For future projections of coastal processes and the protection of coasts the numer-
ical modelling of
sediment dynamics
(Part V) plays a key role. Soomere and Healy
use the concept of the equilibrium beach profile as an adequate tool for their analy-
sis of Estonian beaches. As an example, beach parameters and long-shore transport
patterns are evaluated for Pirita beach based on a granulometric survey and long-
term simulation of wave climate . It is demonstrated that net sand changes for such
beaches can be estimated directly from the properties of the equilibrium profile, land
uplift rate, and loss or gain of the dry beach area. Meyer et al. use the southern coast
of the Baltic Sea as a notable example for the impact of erosion, transport, and accu-
mulation of sediments on coastline change during the Holocene. Since the end of the
Littorina transgression the coastline morphology has been shaped mainly by long-
shore sediment transport controlled by the geological situation and glacio-isostatic
influence. The long-shore sediment transport is driven by wind and consequently
waves shaping young Holocene structures like the Darss-Zingst Peninsula. In order
to model these processes, SEDSIM (sedimentary basin simulation), a stratigraphic
forward-modelling software, has been applied for the Darss-Zingst Peninsula on a
centennial timescale. The results of the numerical experiments show possible impli-
cations to the area of investigation and may serve as a basis for the elaboration of
strategies for the coastal protection against erosion.
Coastal protection strategies require concepts for the sustainable development of
the utilization, i.e.
interaction between a changing environment and society
(Part VI)
