Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Alkor	AL395	01.07.2012 - 03.07.2012		9610 DE_CW_B2.9610.07.02 Schlei estuary Baltic Sea Fehmarn Belt

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Muller Hendrik	Universitat Bremen, Zentrum fur Marine Umweltwissenschaften	Kiel	Kiel

Ziel der Reise / Objectives of Cruise:

High resolution in-situ measurements of surficial sediment porosity and magnetic mineral content is desired to aid and validate morphodynamic models and to provide insight in sediment transport processes related to bedforms and heavy mineral sources. A new bottom towed marine Controlled Source ElectroMagnetic (CSEM) profiler is used to map the electric conductivity and magnetic susceptibility of surficial (<1 mbsf) sediments in-situ with high sensitivity (up to 1 mS/m and 10-6 SI). Data are gathered with sub-meter resolution and are calibrated and further investigated by grab samples. Sidescan Sonar (SSS) data are gathered along CSEM profiles for comparison and joint interpretation. On July 1st, system tests were performed in the southwestern Baltic Sea along a 20 km, coast parallel profile north of Eckernforde Bay in 20 m water depth. The CSEM method is used to measure the concentration of magnetic heavy minerals, eroded from the Schonhagener Kliff. Pre-surveying of the area using SSS and onboard Sediment Echosounder (SES) revealed several rocky outcrops and unknown objects along the desired tracks. Consequently, CSEM profiles were shortened to the accessible area and transit to the Fehmarn Belt was started after sunset. July 2nd and 3rd focused on in-situ mapping of morphology and sediment distribution within a submarine dune field in Fehmarn Belt. The study area has a dimension of 8.6 km by 1.6 km and was fully coved by Sidescan Sonar imaging during the survey. From 7 CSEM profiles covering water depths from 10-23 m over a total length of more than 60 km, we identify numerous dune structures with clear asymmetric porosity distribution and enrichment of magnetic fines in dune troughs of varying magnetite content and porosity. 18 grab samples were analyzed to aid in-situ measurements with details on local grain-size distribution and magnetic mineralogy.

Messungen / Measurements