Geoscience Reference
In-Depth Information
diameter. The mareograph records fromWismar, Barth and Saßnitz which represent
the relative sea-level rise in these study areas, show a secular rise of 1.4, 1.0 and
In these areas, peat samples from both basal peat layers (sensu Lange and Menke
onshore and ship-based offshore surveys. To evaluate the sea-level control, the sam-
ples were checked for the intensity of marine influences using pollen, diatoms and
14
C-AMS dated. The data set was extended by datings from both underwater in situ
finds of tree stumps and archaeological finds (bones and woods). In a few cases,
previous
14
C dates from basal peat layers were considered, which were convention-
ally analysed. All age data were calibrated to calendar years before present (year
confidence inter-
val in the calendar age ranges was used in the construction of the sea-level curves.
To estimate the altitude error, all sample depths were related to recent mean sea
level. Considering the many errors possible when relating the position of the sam-
ples to the former sea level, its altitude can be determined with an accuracy of -0.1
to -0.5 m for precisely levelled sampling sites and +0.2 to -0.8 m for all other
sites. These age-depth ranges were used for the construction of the relative sea-level
To determine the pre-transgressional relief, the distribution of the coastal sed-
iments, their thickness and facies were surveyed extensively by means of motor
hammer-driven drilling equipment. Ground penetration radar (GPR) surveys were
carried out for layer tracing between the auger holes and for recognizing internal
drained areas where introduced saltwater prevented useful measurements (Lampe
Sediment echosounding (SES) surveys were made off Zingst, Rügen and Usedom,
using an INNOMAR SES-96 set. Signal recording was restricted to 10 or 15 m
below the sediment surface.
To estimate the volumes of the barriers, all information from geological maps,
drilling results and GPR surveys regarding the depth of the transgression contact
were gathered and checked against each other. Based on these data the pre-
transgressional land surface was modelled using an ordinary kriging algorithm from
elevation model from the State Survey Office was used and for consistency rea-
sons was recalculated to the same resolution as the surfaces modelled. On average
the modelled surface deviates less than 10% from measured depths. The difference
between the pre-transgressional land surface and the recent land surface represents
the volume of the sediments accumulated under marine-brackish or aeolian condi-
tions. This volume was recalculated to match a volume assumed to have been eroded
from neighbouring Pleistocene feeder cliffs.
σ