From 19th November to 19th December 2004 BGR conducted a marine geophysical cruise between 34°S and 36°S off Uruguay and between 46°S and 50°S off Argentine. The main research objective was to contribute to a better understanding of the initial breakup and the early opening of the South Atlantic. In continuation of our former work on the South Atlantic continental margins off Argentina, Brazil, Uruguay, Namibia and South Africa marine geophysical research (multi-channel seismics, refraction-/wide-angle reflection seismics, magnetics and gravity) was performed in close cooperation with the Argentine and Uruguayan authorities Comisión Nacional del Límite Exterior de la Plataforma Continental (COPLA) of Argentina and Servicio de Oceanograficia, Hidrograficia y Meteorologia de la Armada (SOHMA) of Uruguay. Multi-channel seismic lines with a total length of 3,754 km and additional 3540 km with the other geophysical methods were acquired . Along two lines refraction-/wide-angle reflection seismic work was carried out. The preliminary analyses of the new seismic data show different images of the crustal structures between Uruguay and southern Argentine with regard to the distribution and volume of offshore volcanic rocks (seaward dipping reflector sequences, SDRS) along the South American Atlantic margin. On the northern profiles between 34°S and 36°S one single well developed wedge of SDRS is present. Although the landward termination (‘feather edge’) on most of the lines is masked by multiples the average total width of the wedge across the margin seems to be 90 – 100 km and is very constant for this margin segment. This is strong contrast to the results from former cruises (BGR87, SO85 and BGR98) which covered the area between 38°S and 45°S. There, the SDRS showed distinct multiple wedges which in some places extend over 120 km across the continental slope. The investigation of the sedimentary section yielded that in the area off Uruguay widespread bottom simulating reflectors (BSR) are present. This indications for stable gas hydrates cover a total area of 7000 km2. One major aim of the cruise was to cover the transition between a volcanic passive margin and a non-volcanic passive resp. sheared margin. This was accomplished in the southern part of the investigated area. Two EW-trending profiles across the Argentine shelf into the Argentine Basin still show indications for SDRS but these structures are only 25 – 30 km wide. The profiles which extend from the NE to the SW crossing the Agulhas-Falkland Fracture Zone (AFFZ) onto the Falkland Plateau show the typical trend of a sheared margin. At the northern rim of the Falkland Plateau a set of small pre-rift half grabens were found indicating pre-rift extensional tectonic phases. The magnetic data in the area off Uruguay show lineations which are preliminary interpreted as chrons M0 to M3. This might indicate that the first (oldest) oceanic crust was created at a time around the magnetic polarity reversal between the normal interval M4 and the reversed interval M3 (126-127 Ma). Together with existing data from previous cruises this indicates that the breakup of the South Atlantic started further South because there magnetic chrons back to M9 (130 Ma) were identified. In the southernmost part of the margin at 47°S only the magnetic lineations M0 to M4 were identified in the oceanic domain Nevertheless, it is likely that between M4 and the assumed position of the continent ocean boundary/transition (COB/COT) older oceanic crust exists that for some reasons does not show correlatable lineations. The the free-air gravity map is dominated by the main topographic and structural features in the survey area. Rifted continental margins are characterized by prominent free-air gravity anomalies elongated parallel to the ocean-continent transition. The continental slope is considerably steeper in the North off Uruguay than in the South and thus the gravity high is much more pronounced in the North than in the South. The simple Bouguer anomaly map also shows the difference between the more gentle and wider continental slope in the South and the steeper slope in the North. The lowest Bouguer gravity values are found in the area of the basins on the continental shelf. Especially the Salado Basin in the prolongation of the Rio de la Plata and the Colorado Basin at about 40°S are indicated by Bouguer gravity anomaly highs. The interpretation by forward density modelling shows, however, the presence of SDRS units in the North of relative high density in the area of the continental slope. Whereas the modelling shows no indications for such volcanic bodies in the South. Although the MCS data indicate a small SDRS wedge but this body may be too small to cause an anomaly.From 17th April to 6th June 2003 BGR conducted a marine geophysical cruise between 30°S and 38°S off the Atlantic coast of South Africa. The main research objective was to contribute to a better understanding of the initial breakup and the early opening of the South Atlantic. In continuation of our former work on the South Atlantic continental margins off Argentina, Brazil, Uruguay and Namibia marine geophysical research (multi-channel seismics, wide-angle refraction seismics, magnetics and gravity) was performed in cooperation with the Petroleum Agency South Africa (PASA). Multi-channel lines with a total lenght of 3,260 km, and additional 1,365km, with the other geophysical methods were acquired. Combined onshore/offshore refraction seismic work in cooperation with GeoForschungsZentrum Potsdam (Germany) and the Council for Geoscience (South Africa) was also part of the program.
From 17th April to 6th June 2003 BGR conducted a marine geophysical cruise between 30°S and 38°S off the Atlantic coast of South Africa. The main research objective was to contribute to a better understanding of the initial breakup and the early opening of the South Atlantic. In continuation of our former work on the South Atlantic continental margins off Argentina, Brazil, Uruguay and Namibia marine geophysical research (multi-channel seismics, wide-angle refraction seismics, magnetics and gravity) was performed in cooperation with the Petroleum Agency South Africa (PASA). Multi-channel lines with a total lenght of 3,260 km, and additional 1,365km, with the other geophysical methods were acquired. Combined onshore/offshore refraction seismic work in cooperation with GeoForschungsZentrum Potsdam (Germany) and the Council for Geoscience (South Africa) was also part of the program.
Der Versuch der Anrainerstaaten im Südatlantik ein Schutzgebiet für Wale einzurichten, ist gescheitert. Der Schutzgebietsvorschlag erzielte in der Abstimmung der 66. Jahrestagung der Internationalen Walfangkommission im slowenischen Portoroz am 25. Oktober 2016 nicht die erforderliche Drei-Viertel-Mehrheit. Argentinien, Brasilien, Gabun, Südafrika und Uruguay hatten beantragt, ein 20 Millionen Quadratkilometer großes Meeresgebiet zwischen der Ostküste Südamerikas und der Westküste Afrikas zur Schutzzone für Wale zu erklären, scheiterten jedoch am Widerstand von Pro-Walfang-Staaten.
Die erste Vertragsstaatenkonferenz der Stockholm-Konvention über langlebige organische Schadstoffe (Persistent Organic Pollutants = POP) hat in Punta del Este (Uruguay) getagt. Die etwa 800 Teilnehmer aus 130 Staaten setzten ein Gremium ein, das Vorschläge zur Erweiterung der Liste der besonders gefährlichen Substanzen ("das dreckige Dutzend") bewerten soll. Vier zusätzliche Stoffe wurden bereits vorgeschlagen. Ziel ist der weltweite Ausstieg aus der Produktion dieser Stoffe.
Vom 15. bis 18. September 2014 tagte in Portoroz, Slowenien, die 65. Tagung der Internationalen Walfangkommission. Auf der Tagung standen unter anderen der von Dänemark vorgelegte Vorschlag zur Walfangquote für die indigene Bevölkerung Grönlands, der japanische Vorschlag zu Fangquoten für Minkwale für den kleinen Küstenwalfang, die Ausweisung eines Walschutzgebietes im Südatlantik sowie eine Resolution zum zukünftigen Umgang mit Walfangprogrammen zu Forschungszwecken. Mit qualifizierter Mehrheit verabschiedet wurde der dänische Vorschlag, Fangquoten für den indigenen Walfang der Ureinwohner Grönlands festzulegen. Die IWC lehnte den Vorschlag Japans für die Genehmigung des Fangs von jährlich 17 Minkwalen durch kleine Küstenwalfangschiffe zum lokalen Verbrauch ab. Der Vorschlag Neuseelands für eine Resolution über die praktische Umsetzung des IGH-Urteils zum Wissenschaftswalfang wurde mit einfacher Mehrheit verabschiedet. Die Resolution sieht insbesondere vor, dass die von den IWC-Mitgliedern eingereichten Walforschungsprogramme künftig zunächst vom IWC-Wissenschaftsausschuss hinsichtlich ihrer Vereinbarkeit mit dem IGH-Urteil umfassend geprüft werden. Brasilien, Argentinien, Südafrika und Uruguay legten erneut einen Antrag auf Ausweisung eines Walschutzgebietes im Südatlantik vor. Der Vorschlag fand jedoch nicht die erforderliche Dreiviertel-Mehrheit.
Im Vorhaben wurden Politiken bezüglich der Nutzung natürlicher Rohstoffe von ausgewählten außereuropäischen Ländern über fast drei Jahre hinweg beobachtet und analysiert. Basierend auf einem Screening von 121 Ländern wurden folgende zwölf Länder für das Monitoring ausgewählt: Chile, China, Indonesien, Japan, Marokko, Neuseeland, Ruanda, Singapur, Südafrika, Uruguay, USA und die Vereinigten Arabischen Emirate. Die Ergebnisse zeigen, dass in allen untersuchten Ländern verschiedene politische Ansätze zur Erhöhung der effizienten Nutzung von Rohstoffen verfolgt werden, auch wenn Ausrichtung, Umfang und Umsetzung in den Ländern unterschiedlich sind. Veröffentlicht in Texte | 05/2023.
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