Katrin Schwalenberg

Bundesanstalt für Geowissenschaften und Rohstoffe | BGR

We conducted three-component electric self-potential, EM induction-loop and magnetic mapping of seafloor massive sulphides (SMS) in the Indian Ocean. Two different deep-towed vehicles have been used to perform high resolution mapping at altitudes of 50 m and 2-3 m above seafloor, respectively. The multi-parameter datasets are expected to provide mo...

We conducted three-component electric self-potential, EM induction-loop and magnetic mapping of seafloor massive sulphides (SMS) in the Indian Ocean. Two different deep-towed vehicles have been used to perform high resolution mapping at altitudes of 50 m and 2-3 m above seafloor, respectively. The multi-parameter datasets are expected to provide mo...

The study of offshore freshened groundwater (OFG) is gaining importance due to population growth and environmental pressure on coastal water resources. Marine controlled source electromagnetic (CSEM) methods can effectively map the spatial extent of OFG systems using electrical resistivity as a proxy. Integrating these resistivity models with sub‐s...

Marine geophysical methods provide access to the third dimension of seafloor massive sulphide (SMS) deposits and are crucial exploration components to evaluate their resource potential for mining prospects. Furthermore, they allow the identification and mapping of buried deposits beneath a few meters of sediments or basaltic talus rocks. Geophysica...

We present combined electromagnetic, induced polarization, self-potential and magnetic survey results of seafloor massive sulphide (SMS) target areas in the Indian Ocean. The data have been collected using BGR’s deep-sea GOLDEN EYE CSEM profiler for high-resolution geophysical mapping and newly acquired Vulcan E-field receivers for self-potential m...

Im Rahmen des INDEX-Projektes untersucht die BGR submarine polymetallische Massivsulfid-Vorkommen in der Tiefsee und hält seit 2015 eine Lizenz der Internationalen Meeresbodenbehörde (ISA) zur Exploration einer Fläche von 10 000 km² entlang des Zentral- und Südöstlichen Indischen Rückens. Es finden jährliche Forschungsexpeditionen zu den Lizenzgebi...

For millennia, humans have gravitated towards coastlines for their resource potential and as geopolitical centres for global trade. A basic requirement ensuring water security for coastal communities relies on a delicate balance between the supply and demand of potable water. The interaction between freshwater and saltwater in coastal settings is,...

For millennia humans have gravitated towards coastlines for their resource potential and as geopolitical centres for global trade. A basic requirement ensuring water security for coastal communities relies on a delicate balance between the supply and demand of potable water. The interaction between freshwater and saltwater in coastal settings is, t...

Marine electromagnetic methods provide useful and independent measures for the identification and quantification of submarine gas hydrates. The resistivity of seafloor sediments, drawn from area-wide electromagnetic data, mainly depends on the sediment porosity and the nature of the pore fluid. Gas hydrates and free gas are both electrically resist...

Methane seeping from the seafloor, particularly in shallow shelf-regions, is one source of atmospheric methane, but exact amounts are still discussed. This hold for natural seepages, but also for methane, which may escape from active and abandoned oil & gas wells. During research cruise HE537 (July 2019) and MSM98 (January 2021) we studied the seaf...

The Black Sea is known to have extensive direct and indirect indicators of methane hydrates. Since the resistivity of the seafloor increases significantly in the presence of gas hydrates or free gas, marine controlled-source electromagnetics (CSEM) is a suitable method for the investigation of hydrates. We have collected CSEM data in a channel-leve...

Carbonate lithologies host considerable quantities of the Earth's freshwater resources and partially supply a quarter of the global population with drinkable water. In addition, carbonates constitute substantial amounts of the global coastlines, yet it is not known if and how they can sustain freshened groundwater offshore. Here, we use controlled‐...

This study focuses on seafloor methane seep sites and their distribution in the northwestern part of the German North Sea. Methane seepage is a common phenomenon along marine shelves and known to occur in the North Sea, but proof of their existence was lacking in the study area. Using a ship-based multibeam echosounder we detected a minimum of 166...

First reported in the 1960s, offshore freshened groundwater (OFG) has now been documented in most continental margins around the world. In this review we compile a database documenting OFG occurrences and analyze it to establish the general characteristics and controlling factors. We also assess methods used to map and characterize OFG, identify ma...

Marine controlled source electromagnetic (CSEM) data have been analyzed as part of a larger interdisciplinary field study to reveal the distribution and concentration of gas hydrates and free gas in two working areas (WAs) in the offshore Danube fan in the western Black Sea. The areas are located in the Bulgarian sector in about 1500 m water depth...

Gas hydrates are naturally-occurring solid compounds of gas and water within almost all sediment-rich continental margins. Due to the large amounts of methane stored in submarine gas hydrates, they might serve as future reservoirs for offshore marine gas production. Assessing the reservoir characteristics requires reliable estimates of both the gas...

Electromagnetic loop systems rely on the use of non‐conductive materials near the sensor to minimize bias effects superimposed on measured data. For marine sensors, rigidity, compactness, and ease of platform handling are essential. Thus, commonly a compromise between rigid, cost‐effective, and non‐conductive materials (e.g. stainless steel versus...

The German Geophysical Society (Deutsche Geophysikalische Gesellschaft, DGG) was founded in 1922 in Leipzig, Germany, on the initiative of the famous German seismologist Emil Wiechert (1861–1928), known for his fundamental work to record earthquake waves to study the earth's interior. Facing the German historical background of the early 20 th centu...

Seafloor massive sulfides (SMS) are modern equivalents of VMS deposits in the deep ocean and likely become significant sources for base and precious metal supply in the near future. Electrical and electromagnetic methods have shown success in finding SMS deposits and assessing their spatial extent and resource potential. In addition to mineral expl...

The development of geophysical methods for the assessment of spatial extent, composition, and inner structure of seafloor massive sulfide (SMS) deposits is crux to evaluate their resource potential for future deep-sea mining prospects. Challenges to acquire high resolution near-surface electromagnetic (EM) data in such geologically and morphologica...

The development of geophysical methods for the assessment of spatial extent, composition, and inner structure of seafloor massive sulfide (SMS) deposits is crux to evaluate their resource potential for future deep-sea mining prospects. Challenges to acquire high resolution near-surface electromagnetic (EM) data in such geologically and morphologica...

We present an integrated near-surface mapping approach for marine mineral resources and explain field EM data with petrophysical and geochemical sulfide ore analyses. (http://fb.eage.org/publication/content?id=94767) // Introduction: Since the early discovery of a black-smoker complex in 1978 on the East Pacific Rise at 21°N, speculations and expec...

A new deep-sea frequency domain electromagnetic (FDEM) sounding system named GOLDEN EYE has been developed and applied to map active and relict hydrothermal vent fields in the German license areas at the Central and Southeastern Indian Ridges. The spectral electromagnetic data reveal electric conductivity distributions in the shallow subsurface (ap...

The development of geophysical methods for the assessment of spatial extent, composition, and inner structure of seafloor massive sulfide (SMS) deposits is crux to evaluate their resource potential for future deep-sea mining prospects. Challenges to acquire high resolution near-surface electromagnetic (EM) data in such geologically and morphologica...

Zugl.: Berlin, Freie Univ., Diss, 2000.