6 DieKüste, 74 ICCE (2008), 1-17 
1980; Zeiler et al., 2008). Its outline is still recognizable in the present bathymetry of the 
German Bight whereas most of the smaller channel structures are buried below younger 
deposits (Schwarz, 1996). 
2.2.2 Holocene 
After the LGM, melting of the inland ice caps led to a global sea level rise (Fig. 4). At the 
end of the Pleistocene and in the early Holocene, the magnitude of the sea level rise was 
approx. 2.1 m/100 years (Streif, 2002). The southern North Sea basin was flooded around 
9,000 to 8,000 BP, which is documented by tidal flat deposits from that time (Eisma et al., 
1981). The depositional evolution along the German North Sea Coast began between 8,600 
and 7,100 B.P, when the sea level rose from -45 to -15 m below the present German chart 
datum NN (see Fig. 4). At that time, the coastline was presumably located 5-10 km seaward 
of the present one (Sindowski 1973; Flemming and davis, 1994). During this period, tidal 
currents and waves penetrated further into the hinterland and eroded the exposed higher 
parts of the former submerged Pleistocene landscape. Large quantities of reworked sediment 
were shifted landward, building up a wedge-shaped body of Holocene coastal deposits. This 
sediment body, striking parallel to the coastline, has a width of 10 to 25 km. In the Weser- and 
Elbe estuary, its length goes up to 80 to 100 km. While the accumulation wedge tapers off 
towards the mainland, it can reach a thickness of more than 40 m (Ahrendt, 2006) at its 
relatively steep seaward slope. Here it mainly consists of fine- to medium-grained sand. 
With a decelerating sea level rise from 7,000-3,000 BP (Behre, 2003) coupled with an 
increase of the tidal range from 1.3 m to 2.2 m (Franken, 1987), the coastal zone was formed 
by salt marshes, tidal flat deposits and in parts by barrier islands with dunes of a height of up 
to 30 m. With the phase of a slower sea level rise of only 0.11 m /century (Behre, 2003) over 
the last 3,000 years BP, the Wadden Sea area was formed. This area is characterized by a 
complex pattern of marine and terrestrial deposits, reworked postglacial siliclastic drainage 
material of the underlying Pleistocene drainage deposits as well as several peat layers, which 
were deposited between tidal, brackish and lagoonal sediment layers. In the “drowning” 
landscapes, an also rising ground water table resulted in wide-ranging water logging and the 
formation of peat bogs. Although subsequent frequently eroded by the transgressing sea, 
these basal peat layers often mark the beginning of the Holocene depositional history of an 
area (Streif, 2004). 
Although regional differences exist, which are e.g. due to the palaeo-geomorphology, 
the characteristic series of Holocene deposits consists of strata of fine-grained sand, silt, clay 
and intercalated layers of peat (Fig. 5). Within this alternating sequence, marine and brackish 
deposits overlying peat mark phases of transgression. On the other hand, regressive overlaps 
with peat overlaying brackish and marine sediments indicate a seaward shoreline displace 
ment (Streif, 2004) due to phases of a dropping or - more likely - stagnating or slowly rising 
sea level. 
The surface of the Holocene accumulation wedge is almost flat. Its elevation only varies 
between -f m to +2 m in relation to the German reference datum NN. This also holds for 
the North Frisian islets (Halligen), which are relicts of a former very much wider marshland 
that was partly destroyed by storm surges in the 14 th and 17 th century. On the barrier islands 
along the German North Sea coast, the land elevation is often higher. This is either related to 
the presence of Holocene coastal dunes (East Frisian barrier islands) or to a combination of 
Holocene deposits combined with elevated cores of Pleistocene (Amrum and Fohr Island)