Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Maria S. Merian	MSM35	20.01.2014 - 05.02.2014		Black Sea

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Schwalenberg Katrin	Bundesanstalt fur Geowissenschaften und Rohstoffe, Hannover	Varna	Istanbul

Ziel der Reise / Objectives of Cruise:

The aim of Maria S. MERIAN voyage MSM35 was to conduct marine controlled source electromagnetic (CSEM) measurements in the Danube Delta, Black Sea, to identify suitable gas hydrate deposits for a future MEBO drilling test site for methane production and CO2 sequestration in hydrate form. Marine CSEM is a geophysical exploration method to derive the electrical properties, i.e. resistivity of the seafloor. Gas hydrates and free gas are electrically insulating and replace conductive pore fluid. Thus, the formation resistivity is elevated where gas hydrates and free gas are present in the sediment. Cruise MSM35 follows thematically previous cruise MSM34 Legs 1 and 2, where colleagues from GEOMAR, Kiel, and IMST-Seislab, Turkey, collected high resolution 2D and 3D seismic data, OBS data, as well as heat flow data and gravity cores for pore water analysis. Both voyages MSM34 and MSM35 are closely related to the German joint venture project SUGAR – submarine gas hydrate reservoirs. The joint interpretation of the different methods aims at a better evaluation of the free gas / gas hydrate distribution. Based on the preliminary seismic results from MSM34 two working areas have been selected for the CSEM experiments. The target in the first working area is a strong seismic reflector in a buried canyon system of the deeper Danube delta fan in 1400m water depth, and thus within the gas hydrate stability zone. The second area is located at the edge of the hydrate stability field, and is characterized by a slope slide in 600 m water depth. The observed bottom simulating reflector shows anomalous upward warping, and heat flow data show a low thermal gradient which is assumed to be a consequence of the dissolution of gas hydrate caused by submarine slope slides. During cruise MSM35 two marine CSEM systems have been used: 1) a seafloor-towed CSEM system developed at BGR called HYDRA to collect two-dimensional (2D) data along profiles; 2) stationary ocean bottom electromagnetic (OBEM) receivers and a mobile CSEM dipole source called Sputnik by GEOMAR with the aim to collect a local 3D CSEM data set. Both CSEM data sets will be processed and interpreted in terms of the electrical resistivity distribution which can be related to the local and regional gas hydrate and free gas occurrences. The cruise started from Varna, Bulgaria, on January 20th, 2014 and ended in Istanbul, Turkey, on February 5th, 2014. 2D CSEM data have been collected with the bottom-towed HYDRA system along five profiles in both target areas. Two densely spaced 3D CSEM data sets using ocean bottom electromagnetic receivers and Sputnik, a mobile CSEM source are available from both targets areas. Some gaps in the bathymetric map have been filled during bad weather periods using the shipboard Multibeam EM122 system.

Messungen / Measurements