Deutsches Ozeanographisches
Datenzentrum Inventur der Maria S. Merian-Reise MSM20-1 (DOD-Ref-No.20120062)
Inventory of Maria S. Merian Cruise MSM20-1 (DOD-Ref-No.20120062)

Plattform
Platform
Reise-Nr.
Cruise-No.
Zeitraum
Period
Projekt
Project
Arbeitsgebiet
Working area
Maria S. Merian MSM20-1 06.01.2012 - 15.01.2012   Angola Basin South Atlantic Ocean  

Fahrtleiter
Chief Scientist
Institut
Institute
Auslaufhafen
Port of departure
Einlaufhafen
Port of return
Stationskarte
Station map
Schiffsroute
Trackchart
Geissler Wolfram Alfred-Wegener-Institut fur Polar- und Meeresforschung Cape Town Walvis Bay   

Ziel der Reise / Objectives of Cruise:

Continental break-up is closely related to the question regarding the driving forces behind the associated processes. Following a well-accepted hypothesis, mantle plumes are the most important triggers for the separation of continents. Around the head of a plume the upper mantle temperatures are strongly increased. After weakening of the continental crust by horizontal extension the high temperatures cause extensive volcanism, forming flood basalts as parts of so-called Large Igneous Provinces (LIP) on the continents, and in some cases also in the newly formed oceanic basin. Following this hypothesis, in the ideal case flood basalts are deposited on the continents before break-up. After the start of the drifting stage with formation of oceanic crust between the continents, the mantle plume should create an aseismic ridge due to its continuing activity. The aseismic ridge in the adjacent oceanic basin will mark the plume position through space and time. However, such a clear relationship between volcanism on the continents and the adjoining ocean basins is rarely observed on a global scale. Among the best examples on Earth for such a relationship are the Parana/Etendeka flood basalts and the Rio Grande Rise/Walvis Ridges on both margins of the South Atlantic. Expeditions MSM17/1+2 and MSm20/1 were dedicated to investigate critical parameters, like crustal thickness and structure of the underlying Earth's mantle offshore northern Namibia. Our work was led by the assumption that in the uppermost Earth's mantle and in the overlying crust structures relating to fossil plume and/or deformation processes are frozen in and can be visualized by geophysical methods. During MSM 20/1 we recovered 12 broadband ocean-bottom seismometers deployed in 2011 during MSM 17/2. The acquired passive seismological data will hopefully shed light into the deep lithospheric structure of the study area. Additionally, leg MSm20/1 was a 'floating university' teaching Master students the acquisition, processing and interpretation of hydroacoustic data gathered with the on-board systems EM120, EM1002 and PARASOUND. Transits to and between the stations were used for running the hydroacoustic systems in different water depths (from upper slope down to the deep sea basin) and environments (slope, abyssal plain, Walvis-Ridge). After the successful recovery of all OBS about two days were available for detailed surveys. A nearby sediment wave field on the slope and some structures on the shallow shelf were chosen as targets.

Messungen / Measurements

Institut
Institute
Wissenschaftler
Scientist
Anzahl
Number
Einheit
Unit
Typ der Messungen
Type of measurements
Kommentar
Comments
Daten im DOD
Data in DOD
GEOUNB Schwenk Tillmann 3700 km G73
Single-beam echosounding
ATLAS Parasound, South African schelf, Cape and Angola Basins, Walvis Ridge, Namibian shelf no
GEOUNB Schwenk Tillmann 450 km G74
Multi-beam echosounding
Kongsberg EM1002, Namibian shelf no
GEOUNB Schwenk Tillmann 900 km G74
Multi-beam echosounding
Kongsberg EM120, South African shelf no
GEOUNB Schwenk Tillmann 8 km G90
Other geological or geophysical measurements
Sound Velocity Profile (SVP) tool to calibrate multi-beam echosounding no
AWI Geissler Wolfram 1 km G90
Other geological or geophysical measurements
Multibeam EM 120, EM 1002 yes
AWI Geissler Wolfram 1 n miles H80
Other physical measurements
Underway measurements during the whole trip such as coordinates, depth, meteorological parameter and so on yes

Verankerungen / Moorings

Institut
Institute
Wissenschaftler
Scientist
Typ der Messungen
Type of measurements
Kommentar
Comments
geogr.Breite
Latitude
geogr.Länge
Longitude
Daten im DOD
Data in DOD
AWI Geissler Wolfram G90 Broadband ocean-bottom seismometer ST001 21° 35.9' S 11° 39.2' E -
AWI Geissler Wolfram G90 Broadband ocean-bottom seismometer ST002 20° 44.1' S 11° 12.7' E -
AWI Geissler Wolfram G90 Broadband ocean-bottom seismometer ST011 18° 46.8' S 9° 23.5' E -
AWI Geissler Wolfram G90 Broadband ocean-bottom seismometer ST012 19° 0.0' S 8° 0.0' E -
AWI Geissler Wolfram G90 Broadband oceanbottom seismometer ST003 19° 53.4' S 10° 47.5' E -
AWI Geissler Wolfram G90 Broadband oceanbottom seismometer ST004 18° 52.7' S 10° 17.8' E -
AWI Geissler Wolfram G90 Broadband oceanbottom seismometer ST005 17° 44.9' S 9° 54.1' E -
AWI Geissler Wolfram G90 Broadband oceanbottom seismometer ST006 18° 6.1' S 10° 60.0' E -
AWI Geissler Wolfram G90 Broadband oceanbottom seismometer ST007 19° 55.2' S 9° 46.1' E -
AWI Geissler Wolfram G90 Broadband oceanbottom seismometer ST008 20° 23.4' S 8° 33.4' E -
AWI Geissler Wolfram G90 Broadband oceanbottom seismometer ST009 21° 47.8' S 9° 0.1' E -
AWI Geissler Wolfram G90 Broadband oceanbottom seismometer ST010 21° 18.6' S 10° 13.9' E -
23.3.2024