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Analysis of hydrogen and methane in seawater by “Headspace” method: Determination at trace level with an automatic headspace sampler ArchiMer
Donval, Jean-pierre; Guyader, Vivien.
“Headspace” technique is one of the methods for the onboard measurement of hydrogen (H2) and methane (CH4) in deep seawater. Based on the principle of an automatic headspace commercial sampler, a specific device has been developed to automatically inject gas samples from 300 ml syringes (gas phase in equilibrium with seawater). As valves, micro pump, oven and detector are independent, a gas chromatograph is not necessary allowing a reduction of the weight and dimensions of the analytical system. The different steps from seawater sampling to gas injection are described. Accuracy of the method is checked by a comparison with the “purge and trap” technique. The detection limit is estimated to 0.3 nM for hydrogen and 0.1 nM for methane which is close to the...
Tipo: Text Palavras-chave: Gas; Seawater; Headspace method.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00354/46523/46287.pdf
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Continuous exhumation of mantle-derived rocks at the Southwest Indian Ridge for 11 million years ArchiMer
Sauter, Daniel; Cannat, Mathilde; Roumejon, Stephane; Andreani, Muriel; Birot, Dominique; Bronner, Adrien; Brunelli, Daniele; Carlut, Julie; Delacour, Adelie; Guyader, Vivien; Macleod, Christopher J.; Manatschal, Gianreto; Mendel, Veronique; Menez, Benedicte; Pasini, Valerio; Ruellan, Etienne; Searle, Roger.
The global mid-ocean ridge system, where tectonic plates diverge, is traditionally thought of as the largest single volcanic feature on the Earth. Yet, wide expanses of smooth sea floor in the easternmost part of the Southwest Indian Ridge in the Indian Ocean lacks the hummocky morphology that is typical for submarine volcanism. At other slow-spreading ridges, the sea floor can extend by faulting the existing lithosphere, along only one side of the ridge axis. However, the smooth sea floor in the easternmost Southwest Indian Ridge also lacks the corrugated texture created by such faulting. Instead, the sea floor is smooth on both sides of the ridge axis and is thought to be composed of altered mantle-derived rocks. Here we use side-scan sonar to image the...
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Ano: 2013 URL: http://archimer.ifremer.fr/doc/00136/24771/22950.pdf
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Contrasted hydrothermal activity along the South-East Indian Ridge (130°E-140°E): From crustal to ultramafic circulation ArchiMer
Boulart, Cedric; Briais, Anne; Chavagnac, Valerie; Revillon, Sidonie; Ceuleneer, Georges; Donval, Jean-pierre; Guyader, Vivien; Barrere, Fabienne; Ferreira, Nicolas; Hanan, Barry; Hemond, Christophe; Macleod, Sarah; Maia, Marcia; Maillard, Agnes; Merkuryev, Sergey; Park, Sung-hyun; Ruellan, Etienne; Schohn, Alexandre; Watson, Sally; Yang, Yun-seok.
Using a combined approach of seafloor mapping, MAPR and CTD survey, we report evidence for active hydrothermal venting along the 130°-140°E section of the poorly-known South-East Indian Ridge (SEIR) from the Australia-Antarctic Discordance (AAD) to the George V Fracture Zone (FZ). Along the latter, we report Eh and CH4 anomalies in the water column above a serpentinite massif, which unambiguously testify for ultramafic-related fluid flow. This is the first time that such circulation is observed on an intermediate-spreading ridge. The ridge axis itself is characterized by numerous off-axis volcanoes, suggesting a high magma supply. The water column survey indicates the presence of at least ten distinct hydrothermal plumes along the axis. The CH4:Mn ratios...
Tipo: Text Palavras-chave: Hydrothermal plumes; Mid-ocean ridges; South-East Indian Ridge.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00387/49821/50400.pdf
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Evidence and age estimation of mass wasting at the distal lobe of the Congo deep-sea fan ArchiMer
Croguennec, Claire; Ruffine, Livio; Dennielou, Bernard; Baudin, Francois; Caprais, Jean-claude; Guyader, Vivien; Bayon, Germain; Brandily, Christophe; Le Bruchec, Julie; Bollinger, Claire; Germain, Yoan; Droz, Laurence; Babonneau, Nathalie; Rabouille, Christophe.
On continental margins, sulfate reduction occurs within the sedimentary column. It is coupled with the degradation of organic matter and the anaerobic oxidation of methane. These processes may be significantly disturbed by sedimentary events, leading to transient state profiles for the involved chemical species. Yet, little is known about the impact of turbidity currents and mass wasting on the migration of chemical species and the redox reactions in which they are involved. Due to its connection to the River, the Congo deep-sea fan continuously receives huge amount of organic matter-rich sediments primarily transported by turbidity currents, which impact on the development of the associated ecosystems (Rabouille et al., 2016). Thus, it is well suited to...
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Ano: 2017 URL: http://archimer.ifremer.fr/doc/00363/47410/47403.pdf
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Extensive hydrothermal activity revealed by multi-tracer survey in the Wallis and Futuna region (SW Pacific) ArchiMer
Konn, Cecile; Fourre, E.; Jean-baptiste, P.; Donval, Jean-pierre; Guyader, Vivien; Birot, Dominique; Alix, Anne-sophie; Gaillot, Arnaud; Perez, Florian; Dapoigny, A.; Pelleter, Ewan; Resing, J. A.; Charlou, Jean-luc; Fouquet, Yves.
The study area is close to the Wallis and Futuna Islands in the French EEZ. It exists on the western boundary of the fastest tectonic area in the world at the junction of the Lau and North-Fiji basins. At this place, the unstable back-arc accommodates the plate motion in three ways: (i) the north Fiji transform fault, (ii) numerous unstable spreading ridges, and (iii) large areas of recent volcanic activity. This instability creates bountiful opportunity for hydrothermal discharge to occur. Based on geochemical (CH4, TDM, 3He) and geophysical (nephelometry) tracer surveys: (1) no hydrothermal activity could be found on the Futuna Spreading Center (FSC) which sets the western limit of hydrothermal activity; (2) four distinct hydrothermal active areas were...
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Ano: 2016 URL: http://archimer.ifremer.fr/doc/00347/45848/45505.pdf
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Focused hydrocarbon-migration in shallow sediments of a pockmark cluster in the Niger Delta (Off Nigeria) ArchiMer
De Prunele, Alexis; Ruffine, Livio; Riboulot, Vincent; Peters, Carl A.; Croguennec, Claire; Guyader, Vivien; Pape, Thomas; Bollinger, Claire; Bayon, Germain; Caprais, Jean-claude; Germain, Yoan; Donval, Jean-pierre; Marsset, Tania; Bohrmann, Gerhard; Geli, Louis; Rabiu, Abdulkarim; Lescanne, Marc; Cauquil, Eric; Sultan, Nabil.
The Niger Delta is one of the largest hydrocarbon basin offshore Africa and it is well known for the presence of active pockmarks on the seabed. During the Guineco-MeBo cruise in 2011, long cores were taken from a pockmark cluster in order to investigate the state of its current activity. Gas hydrates, oil and pore-water were sampled for geochemical studies. The resulting dataset combined with seismic data reveal that shallow hydrocarbon migration in the upper sedimentary section was focused exclusively within the pockmarks. There is a clear tendency for gas migration within the hydrate-bearing pockmarks, and oil migration within the carbonate-rich one. This trend is interpreted as a consequence of hydrate dissolution followed by carbonate precipitation...
Tipo: Text Palavras-chave: Anaerobic oxidation of methane; Cluster of pockmarks; Fluid flow; Gas hydrates; Pore-water profiles; Transient state.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00365/47647/47676.pdf
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Geochemical Dynamics of the Natural-Gas Hydrate System in the Sea of Marmara, Offshore Turkey ArchiMer
Ruffine, Livio; Fandino Torres, Olivia; Etoubleau, Joel; Cheron, Sandrine; Donval, Jean-pierre; Germain, Yoan; Ponzevera, Emmanuel; Guyader, Vivien; Dennielou, Bernard; Etiope, Giuseppe; Gasperini, Luca; Bortoluzzi, Giovanni; Henry, Pierre; Grall, Celine; Cagatay, M. Namik; Charlou, Jean-luc; Geli, Louis.
Tipo: Text
Ano: 2012 URL: http://archimer.ifremer.fr/doc/00139/24982/23065.pdf
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Living (stained) deep-sea foraminifera from the Sea of Marmara: a preliminary study ArchiMer
Fontanier, Christophe; Dissard, D.; Ruffine, Livio; Mamo, B.; Ponzevera, Emmanuel; Pelleter, Ewan; Baudin, F.; Roubi, Angelique; Cheron, Sandrine; Boissier, Audrey; Gayet, Nicolas; Bermell-fleury, S.; Pitel, M.; Guyader, Vivien; Lesongeur, Francoise; Savignac, F..
In this preliminary study, we investigate living (stained) foraminifera from the Sea of Marmara. We focus on the faunal composition and geochemical signatures (trace elements, carbon and oxygen stable isotopes) in foraminiferal tests at two deep-sea sites (329 and ~1240 m depth respectively). Documented by ROV observations and sampling, both study areas are heterogeneous (including bacterial mats and carbonate concretions), proximal to cold seeps and consist of dysoxic bottom water (O2<20 µmol/L). The prevailing dysoxia at both study areas restricts foraminiferal diversity to very low values (S<9, H’<0.97). Stress-tolerant species Bolivina vadescens and Globobulimina affinis dominate living faunas at both sites. The highest foraminiferal standing...
Tipo: Text Palavras-chave: Living (stained) benthic foraminifera; Sea of Marmara; Extreme ecosystems; Trace elements; Stable isotopes.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00416/52774/53646.pdf
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Multidisciplinary investigation on cold seeps with vigorous gas emissions in the Sea of Marmara (MarsiteCruise): Strategy for site detection and sampling and first scientific outcome ArchiMer
Ruffine, Livio; Ondreas, Helene; Blanc-valleron, Marie-madeleine; Teichert, Barbara M. A.; Scalabrin, Carla; Rinnert, Emmanuel; Birot, Dominique; Croguennec, Claire; Ponzevera, Emmanuel; Pierre, Catherine; Donval, Jean-pierre; Alix, Anne-sophie; Germain, Yoan; Bignon, Laurent; Etoubleau, Joel; Caprais, Jean-claude; Knoery, Joel; Lesongeur, Francoise; Thomas, Bastien; Roubi, Angelique; Legoix, Ludovic Nicolas; Burnard, Pete; Chevalier, Nicolas; Lu, Hailong; Dupre, Stephanie; Fontanier, Christophe; Dissard, Delphine; Olgun, Nazli; Yang, Hailin; Strauss, Harald; Ozaksoy, Volkan; Perchoc, Jonathan; Podeur, Christian; Tarditi, Corinne; Ozbeki, Eyyup; Guyader, Vivien; Marty, Bernard; Madre, David G; Pitel-roudaut, Mathilde; Grall, Celine; Embriaco, Davide; Polonia, Mina; Gasperini, Lucas; Cagatay, M. Namik; Henry, Pierre; Geli, Louis.
MarsiteCruise was undertaken in October/November 2014 in the Sea of Marmara to gain detailed insight into the fate of fluids migrating within the sedimentary column and partially released into the water column. The overall objective of the project was to achieve a more global understanding of cold-seep dynamics in the context of a major active strike-slip fault. Five remotely operated vehicle (ROV) dives were performed at selected areas along the North Anatolian Fault and inherited faults. To efficiently detect, select and sample the gas seeps, we applied an original procedure. It combines sequentially (1) the acquisition of ship-borne multibeam acoustic data from the water column prior to each dive to detect gas emission sites and to design the tracks of...
Tipo: Text Palavras-chave: Acoustic survey; Authigenic carbonates; Biogeochemistry; Chemical analyses; Cold seeps; Dissolved major elements; Fluid seepage; Geology; In situ Raman analysis; Methane; ROV dives.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00433/54434/55783.pdf
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Organic, Gas, and Element Geochemistry of Hydrothermal Fluids of the Newly Discovered Extensive Hydrothermal Area in the Wallis and Futuna Region (SW Pacific) ArchiMer
Konn, Cecile; Donval, Jean-pierre; Guyader, Vivien; Roussel, Erwan; Fourre, E.; Jean-baptiste, P.; Pelleter, Ewan; Charlou, Jean-luc; Fouquet, Yves.
Two newly discovered hydrothermal vent fields of the Wallis and Futuna region, Kulo Lasi and Fatu Kapa, were sampled for fluid geochemistry. A great geochemical diversity was observed and assigned to the diversity of lithologies as well as the occurrence of various processes. Kulo Lasi fluids likely formed by interaction with fresh volcanic rocks, phase separation, and mixing with magmatic fluid. Conversely, the geochemistry of the Fatu Kapa fluids would be mostly due to water/felsic lavas reactions. In terms of organic geochemistry, fluids from both fields were found to be enriched in formate, acetate, and semivolatile organic compounds (SVOCs): n-alkanes, n-fatty acids, and polyaromatic hydrocarbons (PAHs). Concentrations of SVOCs reached a few ppb at...
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Ano: 2018 URL: https://archimer.ifremer.fr/doc/00431/54245/55571.pdf
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Volcanic and hydrothermal processes in submarine calderas: the Kulo Lasi example (SW Pacific) ArchiMer
Fouquet, Yves; Pelleter, Ewan; Konn, Cecile; Chazot, Gilles; Dupre, Stephanie; Alix, Anne-sophie; Cheron, Sandrine; Donval, Jean-pierre; Guyader, Vivien; Etoubleau, Joel; Charlou, Jean-luc; Labanieh, Shasa; Scalabrin, Carla.
The study area is located at the transition between the northern end of the Tonga Trench and the North Fiji fracture zone, where tectonic movements are reputed to be the fastest in the world. To the southeast of Futuna Island, a broad area of volcanism occurs within a region characterized by a change in the tectonic fabric between a NE-SW oriented volcanic graben and the N-S oriented Alofi ridge. In 2010, the active volcano Kulo Lasi, which represents the most recent volcanic episode in the Futuna area, was discovered in the center of this extensive volcanic zone. Kulo Lasi is a 20 km diameter shield volcano that rises 400 m above the seafloor. It is composed of basaltic to trachy-andesitic lava with no obvious geochemical affinity with the Tonga...
Tipo: Text Palavras-chave: Subaqueous volcanism; Hydrothermal activity; Kulo Lasi caldera; Sulfides; SW Pacific.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00445/55633/57279.pdf
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