Geoscience Reference
In-Depth Information
combinations of these factors in a rather limited area have made north-west Europe
This study focuses on the southern Baltic coast as an ideal object to study the
interplay of these main natural driving forces of coastal development, the influences
of which are controlled by the sediment supply from both cliffs and sea bottom
and the space available for potential sediment accumulation, so-called accommoda-
as a source of uncertainty in sea-level determinations, the eustatic sea-level varia-
tions in this area can be identified more precisely than elsewhere. On a millennium
timescale, neotectonic crustal movements are believed to be insignificant because
over the last 34 My they have varied from 200 m subsidence in the west to 120
0.004 mm/year. However, glacio-isostatic movements have to be considered because
the study area is located in the transition area between the Fennoscandian uplift and
the central European zone where the effects of a decaying glacial forebulge have to
At first, three new relative sea-level curves for the north-east German Baltic coast
will be presented to show the sea-level variation and the tendency and stability of
crustal behaviour. Results from intense onshore and offshore investigations (drilling,
geophysical surveys) will be described to show how the relief prior to the transgres-
sion was formed. These data will be used to calculate the sediment volume of the
barriers, which will be related to the sea-level history. Finally, a preliminary model
of coastal evolution along the southern Baltic will be established which considers
eustatic and isostatic sea-level variation, sediment supply and accommodation.
12.2 Geographic Setting
sists of cliff sections composed of Pleistocene outwash and till, interspersed with
low uplands, barriers, spits and accreting forelands composed of Holocene sand
and, to a very minor extent, gravel. The sea coast provides shelter to a longer shore-
line within the inner bays or lagoons (boddens). The low-lying coastal segments
owe their existence to sediment supplied alongshore from eroding bluffs, which are
less mobile and are believed to act as headlands (hinge points) that help stabilize
adjacent shores. Approximately 70% of the German Baltic Sea coast erodes at an
average rate of 0.34 m/year (Ministerium für Bau, Landesentwicklung und Umwelt
The inner shelf consists primarily of Pleistocene outwash, till and glacial lake
sediment (fine sand and silt). The latter forms large flat sediment bodies offshore of
Usedom (Pomeranian Bight), Zingst (Falster-Rügen plane) and Rostocker Heide.
Extensions of these sediment bodies can also be found landwards of the present
coastline below the barriers. The inclination of the glacial lake sediment surface is
predominantly less than 0.1
◦
and the depths reach from -8 m below the barriers to
