Holocene Evolution of the Southern Baltic Sea Coast and Interplay of Sea-Level Variation, Isostasy, Accommodation and Sediment Supply - The Baltic Sea Basin - page 241

voluminous. To investigate the causes of this barrier size distribution, numerous
drillings and GPR surveys on the barriers, vibrocoring and SES surveys offshore
and in the lagoons were carried out. The extensive fieldwork resulted in an in-depth
knowledge regarding the internal structure and facies distribution of the sediments
from which the relief prior to the transgression can be deduced (Fig. 12.5 shows
examples). In the coastal area from Usedom Island in the east to the Fischland in the
west, the Pleistocene uplands consist predominantly of glacio-fluvial/lacustrine sand
with some till beds and are characterized by a highly undulating relief with eleva-
tions up to +60 m and interjacent depressions down to -20 m. Up to a level of c. -12
to -8 m the depressions are filled with slightly carbonate-bearing fine-to-medium
sand, containing diatoms and molluscs, indicating cold freshwater environments
(Fig. 12.5a ) . The AMS radiocarbon dates imply that they are of Late Glacial Age,
i.e. older than 11,700 year cal BP (cf. Walker et al. 2009 ) . The surface of the Late
Glacial sand dips very slightly to -15 to -18 m northwards towards the proper Baltic
basin where a steeper decline occurs (Fig. 12.1 ) . In the surface, numerous dead ice
depressions are indented and completely filled with interbedded fine sand and silt
(Fig. 12.5b ) . Also, some palaeo-channels intersect the surface. The most prominent
one is the wide Oder palaeo-valley, located east of Rügen (Fig. 12.1 ) . The surface

S N

0

A

m
msl

Marine sand

-5

Marine sand-mud
interbedding

Marine base

-10

100 m

Glacifluvial sand

S

N

Marine fine sand
Marine mud -6

B

msl

Marine base

-10

Peat

Pleistocene fine sand Pleistocene silt

1st multiple

-14

2nd multiple

500 m

E

W

-6

Marine fine sand

Marine coarse sand / gravel

Marine coarse sand / gravel

m
msl

C

Marine fine sand

-10

Marine mud

Pleistocene fine sand

Marine base

Till

-14

1st multiple

500 m

Fig. 12.5 a Example of a GPR record from Hiddensee Island; for location, see line 3 in Fig. 12.6 .
Depth is calculated as 0.053 m/ns. b and c Examples of SES records from the Falster-Rügen plane;
for locations, see lines 1 and 2 in Fig. 12.6 . Depth is calculated as 1,500 m/s