Geological Evolution and Resources of the Baltic Sea Area from the Precambrian to the Quaternary - The Baltic Sea Basin - page 30

Fig. 2.14 Seismo-acoustic profiles 9312, 9522 and 9310b (see Fig. 2.8 forlocationofpro-
files). Profile 9312 shows several steep flexures spaced roughly at the distance of 2 km in an
Upper Devonian succession (Liepaja-Saldus ridge). Profile 9522 indicates a set of steep Permian
faults spaced in a 0.5-2-km range and cutting Upper Devonian sediments. Profile 9310b crosses
the southern part of the Liepaja-Saldus ridge. The Upper Devonian succession shows strong
deformations; some are well reflected in the sea bottom morphology
Fig. 2.15 Left part shows clusters ( grey polygons ) of Permocarboniferous intrusions. Major faults
and wells penetrating intrusions are indicated. Middle part shows magnetic anomalies related to
diabase intrusions in the Baltic Sea. Controlling faults were defined from gravity and magnetic
fields. Right part shows seismic profile across a diabase intrusion north of the well D5-1
2.4.1 Early Ediacaran Tectonic-Igneous Phase
As mentioned above, the break apart of the Rodinia continent was at first reflected
in the Early Ediacaran with the deposition of the Zura formation in western Latvia
and adjacent offshore areas. A dense cluster of drape structures (basement blocks
covered by the Zura formation and Lower Cambrian sediments) occurs in the
Zura depression (Brangulis and Kanevs 2002 ) . Similar drape structure clusters
were identified in westernmost Lithuania, Estonia and the western Kaliningrad area
(Fig. 2.9 ) . Seismic data hint of an extensional kinematic type of those fault blocks
(Fig. 2.9 ) . The fault vertical displacement reaches 170 m. These structures suggest