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

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 the ROV dives, (2) in situ and real-time Raman spectroscopy analysis of the gas stream, and (3) onboard determination of molecular and isotopic compositions of the collected gas bubbles. The in situ Raman spectroscopy was used as a decision-making tool to evaluate the need for continuing with the sampling of gases from the discovered seep, or to move to another one. Push cores were gathered to study buried carbonates and pore waters at the surficial sediment, while CTD-Rosette allowed collecting samples to measure dissolved-methane concentration within the water column followed by a comparison with measurements from samples collected with the submersible Nautile during the Marnaut cruise in 2007. Overall, the visited sites were characterized by a wide diversity of seeps. CO2- and oil-rich seeps were found at the westernmost part of the sea in the Tekirdag Basin, while amphipods, anemones and coral populated the sites visited at the easternmost part in the Cinarcik Basin. Methane-derived authigenic carbonates and bacterial mats were widespread on the seafloor at all sites with variable size and distributions. The measured methane concentrations in the water column were up to 377 μmol, and the dissolved pore-water profiles indicated the occurrence of sulfate depleting processes accompanied with carbonate precipitation. The pore-water profiles display evidence of biogeochemical transformations leading to the fast depletion of seawater sulfate within the first 25-cm depth of the sediment. These results show that the North Anatolian Fault and inherited faults are important migration paths for fluids for which a significant part is discharged into the water column, contributing to the increase of methane concentration at the bottom seawater and favoring the development of specific ecosystems

The Neanderthal teeth from Marillac (Charente, Southwestern France): Morphology, comparisons and paleobiology

Few European sites have yielded human dental remains safely dated to the end of MIS 4/beginning of MIS 3. One of those sites is Marillac (Southwestern France), a collapsed karstic cave where archeological excavations (1967–1980) conducted by B. Vandermeersch unearthed numerous faunal and human remains, as well as a few Mousterian Quina tools. The Marillac sinkhole was occasionally used by humans to process the carcasses of different prey, but there is no evidence for a residential use of the site, nor have any hearths been found. Rare carnivore bones were also discovered, demonstrating that the sinkhole was seasonally used, not only by Neanderthals, but also by predators across several millennia. The lithostratigraphic units containing the human remains were dated to ∼60 kyr. The fossils consisted of numerous fragments of skulls and jaws, isolated teeth and several post-cranial bones, many of them with traces of perimortem manipulations. For those already published, their morphological characteristics and chronostratigraphic context allowed their attribution to Neanderthals. This paper analyzes sixteen unpublished human teeth (fourteen permanent and two deciduous) by investigating the external morphology and metrical variation with respect to other Neanderthal remains and a sample from modern populations. We also investigate their enamel thickness distribution in 2D and 3D, the enamel-dentine junction morphology (using geometric morphometrics) of one molar and two premolars, the roots and the possible expression of taurodontism, as well as pathologies and developmental defects. The anterior tooth use and paramasticatory activities are also discussed. Morphological and structural alterations were found on several teeth, and interpreted in light of human behavior (tooth-pick) and carnivores' actions (partial digestion). The data are interpreted in the context of the available information for the Eurasian Neanderthals

Formes urbaines, mobilité et ségrégation. Une comparaison Lille, Lyon et Marseille (France)

International audienceUrban forms, mobility and segregation. A Lille, Lyon, Marseille (France) comparison. - This paper presents the main results of a research program that looked at the impact of specific polycentric urban forms on commuting patterns and intra-urban segregation. Our results point out three different models. Lyon presents a took-over monocentrism, with visibly and diffuse inequalities. Marseille is characterized by a consuming duocentrism and socially doubly unequal. In Lille we highlight a thrifty polycentrism, but socially excluding. Further research works will test the relevance of these models on other European cities with one million inhabitants.La recherche présentée vise à comparer l'impact de trois formes urbaines polycentriques spécifiques sur les caractéristiques des migrations alternantes et sur la ségrégation intra-urbaine ; nos résultats mettent en évidence trois modèles différents. Lyon présente un monocentrisme relayé, avec des inégalités à la fois apparentes et diffuses. Marseille se caractérise par un duocentrisme consommateur et socialement doublement inégalitaire. A Lille, nous mettons en évidence un polycentrisme économe, mais socialement excluant. De futures recherches devront tester la pertinence de ces modèles-types sur d'autres villes millionnaires européennes

Formas urbanas, movilidad y segregacion

International audienceMobility problems have highlighted the social, economic and environmental requirements to which we must face on a daily basis. This problem is particularly acute in urban areas -in the sense of geographical and functional-, hence we got off on the analysis of interactions between urban lifestyle and daily mobility features. Only by combining the environmental and social dimension can reach the sustainable city. Our empirical study focuses on three specific cases, through which we will study the mass transport model used and the characteristics of urban expansion, to determine if the polycentric practices help or hinder the social mix.Los problemas de movilidad han puesto de relieve las dificultades sociales, económicas y medioambientales a las que hemos de enfrentarnos de manera cotidiana. Esta problemática es más aguda en las áreas urbanas -en sentido del reparto geográfico y funcional-, de ahí que nos hayamos detenido en el análisis de las interacciones entre la forma de vida urbana y las características de movilidad diaria. Sólo conjugando la dimensión medioambiental y la social se puede llegar a la ciudad sostenible. Nuestro estudio empírico se fija en tres casos concretos, a través de los que vamos a estudiar el modelo de transporte colectivo utilizado, así como las características de expansión urbana, para determinar si las prácticas policéntricas favorecen o perjudican la mezcla social

Urban forms, mobility and segregation: A Lille-Lyon-Marseille comparison

This paper presents the main results of a research programme that looked at the impact of specific polycentric urban forms on commuting patterns and intra-urban segregation. Our results point out three different models. Lyon presents an extended monocentrism, with visible and diffuse inequalities. Marseille is characterized by a consuming duocentrism that is doubly unequal in social terms. In Lille, we highlight a thrifty but socially excluding polycentrism. Further research works will test the relevance of these models on other European cities with over a million inhabitants.La recherche présentée vise à comparer l'impact de trois formes urbaines polycentriques spécifiques sur les caractéristiques des migrations alternantes et sur la ségrégation intra-urbaine. Nos résultats mettent en évidence trois modèles différents. Lyon présente un monocentrisme relayé, avec des inégalités à la fois apparentes et diffuses. Marseille se caractérise par un duocentrisme consommateur et socialement doublement inégalitaire. A Lille, nous mettons en évidence un polycentrisme économe, mais socialement excluant. De futures recherches devront tester la pertinence de ces modèles-types sur d'autres villes millionnaires européennes

Formes urbaines, mobilités et ségrégation : une comparaison Lille - Lyon - Marseille. Rapport final

CPER-GRRT Socio-économie 2000 - 2006Rapport de rechercheCe rapport est articulé autour de quatre chapitres. Le premier chapitre précise le questionnement en matière de lien entre polycentrisme et migrations alternantes. Dans le second chapitre, sont présentées les trois aires urbaines et leurs polarités, notamment les villes nouvelles. Le troisième chapitre aborde les liens mis en évidence entre formes urbaines et migrations alternantes au sein des trois aires urbaines étudiées. Le quatrième chapitre est une première caractérisation de la ségrégation spatiale au sein de ces aires urbaines. Au final, ces deux grandes entrées, par les migrations alternantes et par l'analyse de la ségrégation socio-spatiale, nous permettent de dresser trois formes urbaines types qu'il serait intéressant de tester sur d'autres villes en Europe

Corrigendum to "Multiple gas reservoirs are responsible for the gas emissions along the Marmara fault network"

International audienceThe authors regret a mistake on the value of δ13C of methane for one of the investigated gas samples. This concerns sample MRS-DV3-PE03, taken as end member and for which the correct methane δ13C value is -41.9‰ and not -34‰. The sample was collected at in situ pressure ( 100 bars) from a CO2-rich seep, in a liquid state. The mistake likely results from a partial extraction (i.e. done by expansion of the sampler volume to allow vaporization) of the pressurized sample for subsampling. Additional analyses have been carried out from fully vaporized samples. This error has resulted in updating the geochemical diagrams used for the discussion, and revising both the gas origin for sample MRS-DV3-PE03 and the section entitled "Delineation of sources, reservoirs or migration pathways, and estimation of level of mixing". The conclusion of the manuscript is unchanged. The authors would like to apologize for any inconvenience caused

Multiple gas reservoirs are responsible for the gas emissions along the Marmara fault network

On continental margins, upward migration of fluids from various sources and various subsurface accumulations, through the sedimentary column to the seafloor, leads to the development of cold seeps where chemical compounds are discharged into the water column. MarsiteCruise was undertaken in November 2014 to investigate the dynamics of cold seeps characterized by vigorous gas emissions in the Sea of Marmara (SoM).A previous paper published by Bourry et al. (2009) presented the gas geochemistry of three seeps sampled along three different segments in the SoM. Their findings showed that the seeps were sourced by three different reservoirs. In this paper, seventeen seeps were investigated to determine the gas sources, unravel reservoir contributions, and estimate their level of mixing. The molecular and stable isotope compositions of the gas compounds were determined to establish the empirical diagrams that usually allow to delineate source domains. The results provide insights into the complexities of source mixing within the sedimentary column of the SoM before emission of the gases into the water column. The seep gases originate from deep thermogenic or microbial hydrocarbon sources, or from a CO2-rich source. Microbial sources producing methane from primary methanogenesis have been identified in the Tekirdağand the Çinarcik basins. In addition, six different thermogenic reservoirs or six different pathways of migration are responsible for the supply of gas to the seeps on the highs and in the western basin. Five of them are undergoing biodegradation followed by secondary methanogenesis, thereby providing additional sources of microbial methane to the seeps. Overall, the gases emitted by the seventeen seeps consist of variable mixtures of different components from two or three sources