| Scientists: Hendrik Müller, Benjamin Baasch, Christian Hilgenfeldt, Tilo von Dobeneck
Projects: MARUM Sediment Dynamics SD1, MARUM Neridis III, MARUM-UVigo Neridis II
Summary: Given the high environmental and economic relevance of ocean margins and their geophysical exploration, there is growing need to characterize surficial sediments in coastal and continental shelf systems by more than just their acoustic properties. A newly conceptualized benthic profiling and data processing approach based on controlled source electromagnetic (CSEM) imaging permits to coevally quantify the electric conductivity (~ salinity, porosity and grain-size variations) and the magnetic susceptibility (~ terrigenous or iron mineral content, redox state and contamination level) of shallow marine deposits. This approach has been successfully applied in a number of estuarine and shelf surveys (Baltic Sea, Galician Shelf, NZ Bay of Plenty) with the first and second generation of the benthic EM profiler Neritic Discoverer (NERIDIS II & III). The narrow footprint of the concentric, coaxial CSEM sensor together with a relatively high sampling rate (25 Hz) at multiple frequencies and a tow speed of 3-4 knots enable to cover, resolve and invert sediment patterns of very different lateral extent from sub-meter (e.g., iron ore nodules, UXO) to kilometer scales (e.g., drift bodies, placer deposits) within the same survey operation.
Controlled Source Electromagnetic Seabed Profiler MARUM Neridis III
| | Selected Publications:
Müller H., von Dobeneck T., Hilgenfeldt C., SanFilipo B., Rey D., Rubio B. (2012) Mapping the magnetic susceptibility and electric conductivity of marine surficial sediments by benthic EM profiling Geophysics, 77, E43 - E56 doi: 10.1190/GEO2010-0129.1
Baasch B., Müller H., Oberle F., von Dobeneck T. (2014) Inversion of marine multifrequency electromagnetic profiling data: a new approach to resolve surficial sediment stratification Geophysical Journal International, 200, 438 - 451 doi: 10.1093/gji/ggu406 | |