Deutsches Ozeanographisches
Datenzentrum Inventur der Sonne1-Reise SO230 (DOD-Ref-No.20140023)
Inventory of Sonne1 Cruise SO230 (DOD-Ref-No.20140023)

Working area
Sonne1 SO230 29.12.2013 - 18.02.2014   Mozambique Channel  

Chief Scientist
Port of departure
Port of return
Station map
Jokat Wilfried Alfred-Wegener-Institut fur Polar- und Meeresforschung Durban Durban   

Ziel der Reise / Objectives of Cruise:

The target area for the geophysical experiments on leg SO-230 was the continental margins of central and northern Mozambique. The project aims to investigate its evolution in the Late Jurassic. The classification of the rifted margin along the Zambezi coast will enable comparison with the conjugate margin off East Antarctica. Both the structure of the margins and the geometry of the continent-ocean transition are critical input parameters for geodynamic models to better understand Gondwana break-up. In the first part of the cruise SO-230 we investigated the deeper structure of the continental margin off central Mozambique, namely the Beira High,to better constrain thefabric and evolution of this structure. On January, 5th, we started to deploy 37 Oceanbottom seismometers along a 373 km long profile. After this experiment was finished on January 10th we conducted an extensive magnetic programme to densify the existing magnetic data from expeditions in 2005 (RV Sonne) and 2007 (RV Marion Dufresne) offshore of the Zambezi Delta. Much to our surprise there seems to exist a distinct magnetic pattern across the Beira High which is not typical at all for the remaining margin. In the second partfrom January 20th onwards, we investigated the transition from the rifted continental margin off central Mozambique to the sheared margin (Davie Ridge) of northern Mozambique with four seismic refraction lines.These lines were acquired between January 20th and February 4th. Their south-north spacing varied between 160 to 230 km. The number of OBS rangedbetween 20 to 25 with a spacing of 9-14 km. Their length varied between 180 and 360 km. Since the continental margin and the Davie Ridge are quite narrow structures, the last three northern seismic lines were rather short. The northern margin was investigated in a N-S direction along 580 km to decipher the variations in the crustal fabric of this sheared margin. Along both segments of the Mozambican margin the total length of the seismic profiles is 1360 km, and 127 OBS/OBH were deployed/retrieved along the five deep seismic sounding lines. Unfortunately, the planned landward extension of our deep seismic sound profiles could not be achieved since noresearch permitwas received from the Mozambican authorities. The OBS data quality is moderate to excellent, and will allow achievement of the scientific goals of the project.Magnetic and gravity data were along most of the tracks. In total 12181 km magnetic and 17942 km gravity data were gathered. After the termination of the main deep seismic and magnetic projects at the northern end of our seismic network, we conducted a detailed swath bathymetric survey to investigate neotectonic structures in the Kerimbas Graben. The survey lasted from February 5th to 9th. However, no large scale structures were found neither in the swath bathymetric nor in the sediment Parasound data. They will be investigated/interpreted in greater detail, if the seismic reflection data from leg SO-231 will be available. In total, swath bathymetric (82282 km?) and Parasound data were collected for most of the cruise. Together with the previous and upcoming cruises this is the most extensive scientific data base off eastern Africa allowing interpretataion/understanding of recent sedimentary processes. Finally, Sonne sailed in total 17942 km (9688 nm) during our experiments.

Messungen / Measurements

Typ der Messungen
Type of measurements
Daten im DOD
Data in DOD
AWI Jokat Wilfried 3 stations G02
TV Grab; Location please see cruise report (Table 6.1) . no
AWI Jokat Wilfried 127 deployment G26
Seismic refraction (no.of nautical miles)
Ocean Bottom Seismometers. no
BGRH Schreckenberger B. 12181 km G28
Magnetic measurements
Gradiometer System towed 1 km behind the ship. no
AWI Jokat Wilfried 17942 km G73
Single-beam echosounding
Parasound Sediment Echosounder. no
AWI Jokat Wilfried 17942 km G74
Multi-beam echosounding
Multibeam System SIMRAD. no
AWI Jokat Wilfried 1 n miles G90
Other geological or geophysical measurements
EM120 yes
AWI Jokat Wilfried 7 stations H10
Calibration for the Multibeam System; Cruise report table 5.1. no
AWI Jokat Wilfried 1 n miles H80
Other physical measurements
Underway measurements during the whole trip such as coordinates, depth, meteorological parameter and so on yes