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 | South Atlantic Ocean Angola Basin |
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 | - |