Direct access to the 2018 marine cruises, by clicking below:
Expedition leader: David Graindorge (UBO), Frauke Klingelhoefer (Ifremer - REM/GM/LAD)
Collaborations: Ifremer, University of Western Brittany, University of Perpignan, University of Grenoble, University of French Guyana, University of the Antilles, University of Surinam.
Position: Demera Plateau
Dates: 20th October to 16 November 2016
Research Vessel: L'Atalante
Objectives: The main objective was to understand the origin and formation of an enigmatic underwater plateau offshore French Guyana and the Surinam : the Demerara Plateau.
79 ocean bottom seismometers (OBS) of the Brest instrument pool (Ifremer/IUEM) were used together with the deep sounding seismic equipment of Ifremer.
The first results indicate that the crustal thickness of the plateau is between 25-30 km and that it is covered by thick lava flows.
Expedition VOLT 2
Ricardo Silva Jacinto (Ifremer - REM/GM/LGS)Head of operations :
Geographic zone : Capbreton Canyon, France and Spain
Dates : 20/07-26/07/16
Research Vessel : Thalassa
Objectives : Characterize current turbidity activity in the Capbreton Canyon.
VOLT is the acronym for "Vitesses Observées par profileurs Longrange des courants de Turbidity in the Capbreton Canyon". The priority of the study is to observe turbidity currents and their speed. Consequently, three moorings equipped with current meters and sediment traps were deployed in three observation zones : 500, 1000 and 1500 m depths. To be able to discuss the effects of turbidity activity in the canyon (sedimentary recording, morphodynamism), the study also aims at analyzing short core samples (at the interface) acquired in the three zones of observation and recording the high resolution bathymetric differential (2 m) in the zones of interest (1300 m for the current expedition).
The aim is to observe the currents, measure their speed and the suspended sediment recovered in the sediment traps and then to view the produced sedimentary recording (cores) in the deep area of the canyon, its thalweg and neighbouring terrasses (check if currents are able to supply sediment to the top). The analysis of the superficial layers of the interface cores will provide 210 carbon dating and will foresee the study of benthic foraminifer communities. The foraminifers indicate whether the environment has undergone or not recent hydrodynamic disturbances. This in turn will help us to discuss the frequency of observed events and conclude on their scarcity or regularity.
Lastly, we are also interested in the morphodynamic signature of turbidity currents. Learn how erosion and the generated deposits contribute to the change in shape of the seabed. To meet this objective, we are conducting bathymetric surveys over 2 years. For Volt 2, we deployed the AUV Aster x for high resolution bathymetry in depths between 1300 and 1400 m.
Expedition ANTITHESIS 3
Frauke klingelhoefer (Ifremer - REM/GM/LAD)Project leaders : Boris Marcaillou (IRD - GEOAZUR) ;
Dates : 07th May to 23rd May 2016
Objectives : Acquisition of multi-channel seismic data in the Lesser Antilles subduction zone
The Antithesis 3 cruise was dedicated to the acquisition of multi-channel seismic data in the region previously studied during the Antithesis 1 and 2 cruises. Two of the seismic profiles were located on OBS lines shot during the ANTITHESIS 1 cruise without MCS coverage due to technical problems of the seismic streamer (poor meteorological conditions, damaged streamer...).
The map shows the location of the seismic reflection profiles of the ANTITHESIS 1 expedition in yellow and those of ANTITHESIS 3 in red. All objectives have been fully reached thanks to favourable meteorological conditions. Moreover, the new solid-state seismic streamer allowed to record high quality data. The smooth running of the air canons at a high volume of 6500 cubic inches enabled us to image structures at depths up to 15 km.
The results will help us to complete the wide-angle seismic models of the first expedition, to verify different hypotheses regarding the opening of the Anegada passage and to tie the data of ANTITHESIS into those of the SISMANTILLES cruise.
This expedition also extended the bathymetric coverage of the zone and allowed to obtain additional multi-channel seismic data as well as very high resolution seismic (chirp) data and recordings of the reflectivity of the water column. These will help us to better define the role of fluids in this subduction zone.
Part of the MCS profiles cover the objectives of the ANTITHESIS 1 expedition which we were unable to complete due to technical problems (poor meteorological conditions, damaged streamer...). The aim of this expedition was to conduct seismic reflection profiles along the lines of the wide angle seismic lines already acquired.
The map shows seismic reflection profiles of the ANTITHESIS 1 expedition in yellow and those of ANTITHESIS 3 in red. To date, the objectives have been reached thanks to favourable meteorological conditions. Morever, the new technology of the streamer, called "strong", gives high quality data. The smooth running of the air canons meant that a volume of 6500 cubic inches was deployed enabling to image objectives at great depths.
The results expected will enable us to complete the models of wide-angle seismics of the first expedition, to control the different hypotheses of the opening of the Anegada passage and to correlate the data of ANTITHESIS with those of the expedition SISMANTILLES.
This expedition also widened the bathymetric coverage of the zone and obtained further multi channel seismic data and very high resolution seismics (chirp) of the water column which will help us to better define the role of fluids in this subduction zone.
Expedition PAMELA-MOZ03 and PAMELA-MOZ05
Topic: The formation of passive continental margins
Project leader: Maryline Moulin (leg 1) (IFREMER-REM/GM/LGS)
Collaboration: CNRS-IUEM (Brest), UPMC (Paris 6), IFREMER, Total, IDL-FCUL (Portugal), AWI (Germany), BGR (Germany), IMAF (Mozambique), INP (Mozambique), UNM (South Africa)
Location: Margins of the valley of Natal and East Limpopo, Mozambique Channel
Dates: 11 February to 3rd April 2016
Research Vessel: Pourquoi Pas ?
Objectives: The objectives of the PAMELA-MOZ3 project, a scientific collaborative project between IFREMER, Total and academic partners (UPMC, IUEM, CNRS, Géosciences Rennes1, FCUL, ISEL), are to study the deep geometry of a margin system in order to reveal the structure of a diverging margin segment between two sliding edges and to understand its evolution from pre-rift to post-rift. The results will permit testing of different cinematic hypotheses for the opening of the Indian Ocean and to better constrain them in particular in understanding the transition between sliding movement (East Limpopo and West Natal margins) and diverging, pull-apart movement (North Natal margin). The results could also be compared to those of the margin of Tanzania and to studies conducted by our German colleagues on the margin of Rovuma, another key transition in the region.
Equipment: (SMT) 360 traces, OBS (Ocean Bottom Seismometer), magnetism, gravimetry, bathymetry, ADCP, Coring, Dredging.
Access to the French Oceanographic Cruises Catalogue: PAMELA-MOZ03 and PAMELA-MOZ05
Expedition leader: Ewan Pelleter (Ifremer - REM/GM)
Position: North Atlantic
Days: 30/01/2016 to 13/02/2016
Objectives: The main objective of the LEVE-SMF sea expedition is the development of a methodology to detect deep hydrothermal plumes (> 3000 m) and the acquisition of new bathymetric and imagery data of unexplored zones. The methodology to detect ascending plumes will be developed from the study of two sites known for their intense hydrothermal activity (Snake Pit and TAG).
More specifically, this expedition is part of a national programme on the exploration of polymetallic sulfides in the French permit zone located in the Atlantic and should assist in the preparation of the future sea expeditions (2017 and 2018) and the characterization of hydrothermal environments (BICOSE 2).
Further work will be conducted during the transit between Guadeloupe and the Açores:
- Bathymetric and magnetism survey in the French EEZ around Guadeloupe (contact: J.-F. Lebrun)
- Collection of microplastics throughout the transit (contact: P. Kerhervé)
- Current measurments by ADCP (contact: P. Lherminier)
* General map presenting the work zone and the SMF acquisition profiles (in yellow)