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both the Loissin 1 and the Rügen 5 borehole have additionally reached presum-
ably Neoproterozoic sediments at their final depth (Beier et al. 2001 ) . The most
complete Ordovician section was encountered by the Rügen 5 borehole with more
than 3,000 m intensely deformed Ordovician sediments (Hoth et al. 1993 , Franke
and Illers 1994 ) . The lower and around 120-150-m-thick part (Late Tremadoc) is
mainly characterized by fine-grained sandstones. It is overlain by a more than 1,000-
m-thick black shale formation (Llanvirn) and a formation formed by greywackes,
black shales and siltstones. The upper formation is of Caradocian age and shows
a thickness of more than 2,000 m. The whole Ordovician section shows a multi-
phase Caledonian deformation history and is interpreted to belong to an Avalonian
(peri-Gondwanan) sedimentation area (Beier and Katzung 2001 ) . Most of the other
boreholes in the area have drilled only some 100-200 m into the Ordovician.
All the boreholes of the area show a severe erosion unconformity on top of the
Ordovician and the corresponding sedimentation gap decreases from the north to
the south. Triassic sediments are located on top of the Ordovician in the north-
ern part of Rügen, whereas Middle to Upper Devonian or Lower Carboniferous
sediments form part of the overburden in the southern part and on Usedom
Island.
The Middle Devonian of the area is mainly characterized by a clastic sedimen-
tation which was followed by a marine transgression during the Upper Devonian
and the deposition of marine shales and carbonates. The boreholes have encoun-
tered a Devonian section thickness between some hundred and up to 2,300 m in
the Binz 1 borehole (Hoth et al. 1993 ) . Marine conditions were also typical for the
Visean and the Dinantian. Two main sedimentary facies are described by Hoffmann
et al. ( 2006 ) : a carbonate-dominated shelf facies and a facies which is typically
for graben structures and dominated by shales, siltstones and marlstones. Sediment
thickness varies between some hundred and up to around 2,000 m. During the tran-
sition to the Namurian, the sea became shallower and finally paralic conditions
prevailed and led to the deposition of 100-700-m-thick clastic sections. The fol-
lowing Lower Westphalian sedimentation occurred within deltas, flood plains and
swamps. Several coal seams are therefore typical for the Westphalian A and B.
During the Westphalian C and D, fluvial and limnic sedimentation was more impor-
tant and Stephanian sedimentation occurred partly even under semiarid conditions.
The thickness of the whole Westphalian to Stephanian section reaches around 2,100
m in the Rügen/Vorpommern area (Hoth et al. 2005 ) .
Figure 2.6 shows the location of the boreholes which have drilled to the
Carboniferous and the depth of the Pre-Permian for the Rügen area and also for
the neighbouring parts of the North German basin. The profile in Fig. 2.7 high-
lights the importance of granites and magmatic dykes mainly of Variscan age for the
described area. These magmatic rocks have caused severe coalification anomalies
within Carboniferous and older Palaeozoic sections (Hoth 1997 ) and are partly con-
nected to thick Permocarboniferous volcanic rocks within the North German basin
and the Polish basin. Thickness of clastic Rotliegend sequences is also increasing to
the south into the central basin part of the North German basin. Both figures show
the Rügen area forming the northeastern boundary of the North German basin to the
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