10 Die Küste, 74 ICCE (2008), 1-17 
3.2 Neogene 
Regression continued during the beginning of the Neogene, 23 million years ago (Lou- 
RENS et ah, 2004). At the end of this period during the Pliocene Epoch, the climate became 
colder. The Baltic Sea area was marked by the development of a river system, the Baltic Main 
Stream, flowing in a NE-SW oriented depression, draining NE-Europe and transporting 
huge amounts of fluvial sediments which were mainly deposited as Kaolinitic sand in the 
North Sea basin. This is the material which is dredged offshore in the North Sea today to be 
used for beach- and dune nourishment. 
3.2.1 Pleistocene Development 
The younger history of the Baltic Sea was dominated by decreasing temperatures over 
the past 2.4 million years and at least three glacial periods, when ice was advancing from 
Scandinavia towards NW-Europe. The depression already used by the Baltic Main Stream 
was carved out further by these ice advances, of which the latest formed the specific geomor- 
phological shape of the basins, bays, fjords and coastal areas as we see it today (Fig. 6). Mar 
ginal contours of the ice cover are formed by end-moraines, indicating how far these advan 
ces and sub-advances, representing an oscillating ice front, were reaching. The distance bet 
ween these different contours of the latest ice advance increase from West to East (Fig. 7). 
Between them melt-water sediments composed of silt, sand and gravel have been deposited. 
As such, the amount of sand and gravel below the veneer of the modern, post-littorina marine 
sediments increases from west to east, namely from Schleswig-Holstein via Mecklenburg- 
Vorpommern to Poland. 
The whole south-eastern to south-western part of the Baltic Sea, the coastal areas of 
Latvia, Lithuania, Russia, Poland, Germany and Denmark, are built up of soft-rock Quater 
nary deposits (Winterhalter et ah, 1981), mainly of Weichselian age. On the other hand, 
the northern part of the Baltic Sea is mainly composed of hard rock (Lampe, 1995). There are 
only a few exceptions where hard rock is exposed along the south-western Baltic Sea, e.g. 
parts of Rügen Island (Germany) or Mons Klint (Denmark). Here, cretaceous deposits have 
been pushed up by glaciers during the latest ice advance. 
Glacio-isostatic movement and climatically controlled eustatic sea level fluctuations 
have caused transgressions and regressions in the Baltic Sea and its precursors during the 
Holocene. From the early to middle Holocene, the Baltic Sea underwent 4 evolutionary 
stages (Fig. 8).These were the Baltic Ice Lake, the Yoldia Sea, the Ancylus Lake and the Lit- 
torina Sea (Björk, 1995; Eronen et al., 2001; Lampe, 2005). As a result of the interaction of 
uplift rates and changes in relative sea level alternating fresh-, brackish- and marine water 
conditions occurred. The Holocene history of the precursor of the Baltic Sea started with the 
deglaciation and the opening of several drainage channels around 13,000 years BP. Due to 
these openings, the water-level dropped to at least - 25 m MSL (mean sea level) and caused 
extensive erosion in the lower river courses. During Alleröd, the waterlevel rose again from 
-40 to -20 m MSL (see Fig. 9). This phase (Bölling to Younger Dryas) is called Baltic Ice Lake. 
The opening of the gap at Mt. Billingen around 10,300 years BP due to the continuous retreat 
of the Scandinavian ice sheet from the southern Swedish mountains caused a drop of the 
water table to about -40m MSL (BjöRCK, 1995). The early Holocene incision phase started 
with the Yoldia Sea (Janke, 1978). It was the first connection with the Atlantic - North Sea 
system, which lasted only for some 700 years. By an accelerated isostatic uplift of Southern