Publication Date:
2021-01-28
Description:
The cruise AL527 took place in the Western Baltic Sea in the period 6. – 14.09.2019.
The cruise was carried out as a marine geophysical field course of Kiel University,
supported by BONUS ECOMAP project. Starting and ending point of the cruise was
Kiel. One stopover in Kiel took place during the cruise due to an exchange of parts of
the scientific party (10.09.2019). The main aim of the cruise was to introduce marine
geophysical acquisition to the students including hands-on experience in collecting marine geophysical data. This approach also included a first processing and interpretation
of the data as well as the presentation of the first results.
Two areas in the Western Baltic Sea were the main working areas of AL527. The first
survey area was at Boknis Eck, a part of the Eckernförde Bay. The main objective in this
area was to search for an underwater observatory from the Coastal Observing System
for Northern and Arctic Seas Project (COSYNA), which was operated by GEOMAR
and disappeared end of August 2019. For this purpose, a survey with a bathymetric
multibeam system from the ”Marine Geophysics and Hydroacoustics” working group
(Kiel University) was carried out. Furthermore, an underwater camera system was used
for visual inspections. The second survey area was in the Mecklenburger Bay. The
main objective was a pre-investigation of a buried beach for an upcoming cruise within
the EU-funded project ACT-SENSE. Therefore, 2D reflections seismic, sediment echo
sounder, and multibeam data were acquired. Additionally, 7 gravity cores were taken for
ground trothing and sampling of the buried beach. In order to analyze major tectonic
structures in the Fehmarn Belt and the Mecklenburger Bay, 12 additional seismic profiles
were collected when transiting between the survey areas.
Our investigations showed that a buried beach is located in the Mecklenburger Bay
beneath a layer of mud. The sand deposits have an estimated variable thickness
between 1m and 9m in the survey area. The top of the beach was successfully sampled
with several gravity cores. Further investigations of these cores, together with the
geophysical data, will be take place in the frame of the ACT-SENSE project.
In the acquired bathymetric dataset from Boknis Eck some conspicuous zones could
be identified, where possibly remaining parts of the missing underwater observatory
are located. Unfortunately, it was not possible to validate these zones by the used
underwater camera. These zones should be investigated by divers in the near future,
for a reliable validation.
Type:
Report
,
NonPeerReviewed
Format:
text
Permalink
