Geoscience Reference
In-Depth Information
Fig. 2.8
Sediment thickness of major structural complexes of the Baltic basin.
a
Baikalian
(Ediacaran-lowermost Cambrian);
b
Caledonian (Cambrian to
lower part
of Lower Devonian);
c
Hercynian (
upper part
of Lower Devonian-Carboniferous);
d
Alpine (Permian-Cenozoic)
extends from Lake Ladoga to the Caledonides and has seeds of many localized nar-
row rifts. The Jotnian sediments were intruded by Post-Jotnian diabase sills and
dykes (e.g. diabases in the Kvarken area dated 1268
Sediments of Riphean age are not known from the Baltic Sea area.
The Baltic sedimentary basin was initiated on this type of continental crust dur-
ing Late Ediacaran-Early Cambrian time. It is a special tectonic structure because of
its long-lasting subsidence history reaching from Late Precambrian to Quaternary.
Subsidence rates and patterns varied considerably throughout the Phanerozoic
the basin evolution. The following main geodynamic stages can be distinguished.
±
2.3.1 Failed Rift Stage
The Baltic Sea area was affected by intense magmatic activities during the
Mesoproterozoic. The ages of the rapakivi granites and associated igneous rocks
