MSc Benedict Preu

The overall goal of this thesis is the processing and interpretation of the available seismo-acoustic data sets from the R/V Meteor Cruises M78/3a+b (2009) and M49/2 (2001). This includes high-resolution multichannel seismic data, sediment echosounder (Parasound) data and multibeam bathymetry data. In the frame of MARUM Project SD3 (“Slope architecture and evolution of sedimentary regimes”) the interpretation will be done close to results from sedimentology, geotechnics and geochemistry. In this context the first goal of this study will be mapping and analyzing of the contourite deposition system in the north of Argentina. Mapping of depocentre shifts and areas of deposition and non-deposition in time and space within in the drift accumulations will allow gaining a better understanding of Antarctic water masses and the North Atlantic Deep Water.
The second goal of this study will be a morphological and structural analysis of the Mar de Plata canyon. To gain information about the so far unknown origin and development of this canyon, which is located directly in the confluence zone of Brazil and Malvinas currents, and its interaction with the surrounding current regime is of special paleoceanographic interest.
The last goal of this PhD thesis will be a comparison between the contourite deposition system in the north of Argentina and other comparable systems in boundary settings (e.g. SE Africa).

• Bottom current driven sediment transport
• Water mass boundaries and their impact on sediment dynamics and slope morphology
• Eddy driven sediment transport - benthic storms
• Water column imaging (e.g. nepheloid layers, plankton…) using hydro-acoustic methods
• Paleoceanography of the southern hemisphere since Late Miocene times

• Brazil-Malvinas Confluence / Northern Argentine Continental Margin
  A major Contourite Depositional System (CDS) is studied at northern Argentine continental margin in front of the Rio de la Plata by means of seismo and hydro-acoustic methods including conventional and high-resolution seismics, parametric echosounder and single and swath bathymetry. The study focuses mainly on identifying erosive and depositional features. The morpho-sedimentary characteristics are interpreted jointly with hydrographic data sets characterizing the oceanographic framework, which is dominated by the presence of the dynamic and highly variable Brazil-Malvinas Confluence (BMC). Tracing of these morphological features through time and space allows conclusions on the evolution of the modern water mass stratification.
  Furthermore, in an integrated approach acoustic backscatter data of the water column collected using a parametric echosounder and multiple ADCPs are used to image the cascading of the Malvinas Current.

• Source region of the Agulhas Current / Eastern South Africa - Mozambique
  This study focuses on the linkage between the oceanographic and sedimentological processes in the source region of the Agulhas Current. In particular, the impact of a lee eddy on contouritic deposits is studied southeast of the Limpopo River mouth. High-resolution seismic data is used to described the evolution of this system since Late Miocene times, while hydro-acoustic methods are used to determine the modern influence of this lee eddy on sediment erosion and transport.
  This study is conducted in relation to the SAFARI IODP proposal.

• Upwelling NW Africa / Cape Blanc
  Hydro-acoustic data collected off Mauritania are used to determine the sensitivity of 18, 38 and 75 kHz to particle sizes in relation to optical estimated concentrations. In the upcoming months backscatter data recorded using the parametric echosounder PARASOUND P70 (ATLAS HYDROGRAPHIC) and ADCPs will be analyzed jointly with optical turbidity measurements acquired by means of CTD and particle camera profiling. Further, the vertical plankton migration will be analyzed during day and night cycles.

• Mediterranean Outflow Water / Gulf of Cádiz
  Coming soon...

04/2011 - 05/2011 R/V Maria S. Merian MSM18/1 (NW Africa)
Project: Physical and biochemical studies in the subtropic and tropic Atlantic

05/2009 – 07/2009 R/V Meteor cruise M78/3a+b (South America)
Project: Sediment transport off Uruguay and Argentina

03/2008 R/V Meteor cruise M75/3 (South Africa)
Project: Western Indian Ocean Climate and Sedimentation (WINOCS)

10/2007 R/V Meteor cruise M74/2 (Makran)
Project: Nitrogen Cycle, Cold Seeps, Carbonate Platform Development in the northwestern Indian Ocean

04/2007 R/V Meteor cruise M72/3b (Black Sea)
Project: Methane and methane hydrates within the Black Sea: Structural analyses, quantification and impact of a dynamic methane reservoir (METRO)

Peer reviewed articles:

Talks and Poster Presentations:

Since 04/2009 PhD student at the University Bremen/MARUM
Supervisor: Prof. Dr. V. Spieß

11/2008 – 03/2009 Scientific researcher at the University Bremen/MARUM
D4: ‘Geotechnical and geophysical seabed characterisation’

2006 – 2008 Studies of Marine Geosciences (M.Sc.) at University Bremen
Focus: Marine seismics, global change, marine environmental archives
Thesis: Seismic interpretation of contourite drifts and their controlling dynamic processes in the transition from Mozambique Current to Agulhas Current in front of Limpopo River

2003-2006 Studies of Geosciences (B.Sc.) at University Bremen
Focus: Marine Geology and marine geophysics
Thesis:Regional influences on the coastal upwelling of Northwest Africa