Consulta: creatorFacets:"Imbert, Patrice"
Registros recuperados: 9
Data/hora: 09/06/2024 06:01:42

Sediment damage caused by gas exsolution: a key mechanism for mud volcano formation
Provedor de dados: 5
Autores: Blouin, Arthur; Sultan, Nabil; Callot, Jean-paul; Imbert, Patrice.
Gassy sediments are common in marine environments and are characterized by a specific mechanical behavior significantly different from that of water-saturated sediments. It is shown that gas causes damage and initiates fractures in sediments. To define the controlling parameters dominating the damage process during gas exsolution and its consequences in terms of hydro-mechanical behavior, we developed a specific consolidation apparatus to test sediments collected from the active Absheron Mud Volcano. Indeed, mud volcano formation is initiated by gas exsolution and subsequent mud generation at depth from stratified sediments. Gas was generated in the samples by circulating carbonated water through the fine-grained sediments, then decreasing the total...
Tipo: Text
Palavras-chave: Consolidation testing; Gas exsolution; Gassy sediments; Sediment damage; Mud volcano.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00588/70043/67974.pdf

Evolution model for the Absheron mud volcano: from in-situ observations to numerical modeling
Provedor de dados: 5
Autores: Blouin, Arthur; Imbert, Patrice; Sultan, Nabil; Callot, Jean-paul.
The morphology of mud volcanoes (MV) has been extensively studied over the last few decades. Although recent research has begun to focus on deep processes and structures, little is known about mud generation mechanisms. This study aims to investigate the feeder system and formation of an active kilometer‐scale MV by relying on a 3‐D seismic survey and an in‐situ dataset on the Absheron anticline (South Caspian Basin). Seismic data show a depleted area in the Anhydritic Surakhany Formation (ASF), whose mineralogical composition fits with surface mud. Well data show that the ASF is a succession of evaporitic beds and low temperature shales near its fracture pressure. Biostratigraphic analysis confirms a Pliocene origin for the mud, suggesting that the ASF...
Tipo: Text
Palavras-chave: Mud volcano; Pore pressure; Methane; Modeling; Seismic.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00481/59304/62057.pdf

Sea-level change and free gas occurrence influencing a submarine landslide and pockmark formation and distribution in deepwater Nigeria
Provedor de dados: 5
Autores: Riboulot, Vincent; Cattaneo, Antonio; Sultan, Nabil; Garziglia, Sebastien; Ker, Stephan; Imbert, Patrice; Voisset, Michel.
A series of pockmarks observed at the seabed matches well the perimeter of a large submarine landslide, called NG1, located on the outer shelf and continental slope of the Eastern Gulf of Guinea. NG1 extends over 200 km2, is covered by a 120-m thick sedimentary layer which tapers downslope, and has an internal structure clearly identified in 3D seismic data consisting of three adjacent units on the upper continental slope. The pockmarks above NG1 have a diameter of several tens of meters and reveal distinct origins: (1) linked to &gt;500 m deep fluid reservoirs, (2) rooted in NG1 internal discontinuities between NG1 units, and (3) well above NG1, superficially rooted in a regional conformity (D40), which marks the lowest sea level of the Marine Isotope...
Tipo: Text
Palavras-chave: Pockmarks; Fluid seepage; Submarine landslide; Sea-level changes; Piezocone; Niger Delta.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00159/27031/31906.pdf

Mud volcano growth by radial expansion: Examples from onshore Azerbaijan
Provedor de dados: 5
Autores: Odonne, Francis; Imbert, Patrice; Dupuis, Matthieu; Aliyev, Adil A.; Abbasov, Orhan R.; Baloglanov, Elnur E.; Vendeville, Bruno C.; Gabalda, Germinal; Remy, Dominique; Bichaud, Victoria; Juste, Rémy; Pain, Maëlys; Blouin, Arthur; Dofal, Anthony; Gertauda, Mathieu.
We investigated the mode of growth of flat-topped mud volcanoes, through the study of three active edifices onshore Azerbaijan: they are the Bozdag-Guzdek, the Ayazakhtarma and the Akhtarma-Pashaly mud volcanoes. The three edifices are up to 80 m high and 3 km wide, and the recurrence time between eruptions from a few months to a few years. Surface changes during and between eruptions were documented by a combination of mapping from satellite pictures, repeated direct observation over five years and structural analysis. In addition, resistivity profiles and microgravity measurements were used to decipher their subsurface geometries. We interpret the flat-topped character of the mud volcanoes as the result of rapid “isostatic” readjustment of a brittle...
Tipo: Text
Palavras-chave: Flat-topped mud-volcanoes; Azerbaijan; Growth of flat mud volcanoes; Resistivity-gravity data; Low-density mud at depth; Mudflows stacking; Soft mud.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00515/62689/67076.pdf

Pockmarks on the South Aquitaine Margin continental slope: The seabed expression of past fluid circulation and former bottom currents
Provedor de dados: 5
Autores: Michel, Guillaume; Dupre, Stephanie; Baltzer, Agnes; Ehrhold, Axel; Imbert, Patrice; Pitel, Mathilde; Loubrieu, Benoit; Scalabrin, Carla; Lazure, Pascal; Marie, Louis; Geldof, Jean-baptiste; Deville, Eric.
Inactive and mostly elongated pockmarks of 100–200 m in dimension were recently discovered on the South Aquitaine Margin continental slope. They are distributed at water depths greater than 350 m in both interfluve and sediment-wave areas, and are strongly controlled by the sedimentary morphology and architecture. Water column and seafloor backscatter and sub-bottom profiler data do not exhibit present-day or past gas evidence, e.g., massive and continuous gas releases at the seabed and fossil methane-derived authigenic carbonates. It is thus proposed that the pockmarks originated from a shallow source and result from relatively recent and short-duration gas or water expulsion events. Former near-bottom currents may have contributed to the elongation of...
Tipo: Text
Palavras-chave: Pockmark; Fluid; Seabed morphology; Aquitaine slope; GIS; Currents.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00413/52491/53279.pdf

Evolution model for the Absheron Mud Volcano: from stratified sediments to fluid mud generation
Provedor de dados: 5
Autores: Blouin, Arthur; Sultan, Nabil; Pierron, Alexandra; Imbert, Patrice; Callot, Jean‐paul.
Submarine mud volcanoes are one of the most spectacular methane expulsion features at the seafloor and they represent a significant geohazard worldwide. In this work we focus on the physical processes controlling the initiation and early evolution of the Absheron mud volcano (AMV). Our analyses were carried out based on basin modeling calibrated thanks to existing seismic interpretation of the AMV, analysis of sediment samples from seabed, and data from two exploration wells. Acquired laboratory geotechnical data allowed us to derive laws considering the impact of gas exsolution on host sediment behaviors. In this study, we identified key geological and physical conditions that led to mud volcano formation: by coupling diffusion processes with...
Tipo: Text
Palavras-chave: Mud volcano; Numerical modeling; Geohazard; Sediment remobilization; Methane.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00658/77002/78258.pdf

Fluid escape features as relevant players in the enhancement of seafloor stability?
Provedor de dados: 5
Autores: Riboulot, Vincent; Imbert, Patrice; Cattaneo, Antonio; Voisset, Michel.
Fluid migration within the sedimentary column contributes significantly to slope failure and pockmark formation and can be an effective triggering mechanism to generate submarine landslides. Pockmarks are thus commonly listed among geohazards. Contrary to these accepted notions, we propose here an alternative view of pockmarks with an example from the Eastern Niger Submarine Delta: Pockmarks and associated chimneys may increase or modify the shear strength of sedimentary layers and locally enhance seafloor stability. The analysis of two 3D seismic volumes shows that a landslide deposit divides into two branches around a cluster of three pockmark chimneys, interpreted to impede its further development. The morphological characteristics of a slide...
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00512/62348/66614.pdf

Origin of an enigmatic regional Mio-Pliocene unconformity on the Demerara plateau
Provedor de dados: 5
Autores: Pattier, France; Loncke, L.; Imbert, Patrice; Gaullier, V.; Basile, C.; Maillard, Alexandre; Roest, Walter; Patriat, Martin; Vendeville, B. C.; Marsset, Tania; Bayon, Germain; Cathalot, Cecile; Caprais, Jean-claude; Bermell, Sylvain; Sotin, Christine; Hebert, Bertil; Mercier De Lepinay, Marion; Lebrun, J. F.; Marcaillou, B.; Heuret, A.; Droz, Laurence; Graindorge, David; Poetisi, E.; Berrenstein, H.
The Demerara plateau, located offshore French Guiana and Suriname, is part of a passive transform continental margin particularly prone to develop slope instabilities, probably in relation to the presence of a free distal border along its steep continental slope. Slope failure occurred at different periods (Cretaceous to Neogene) and shows an overall retrogressive evolution through time. Upslope these failure headscarp, an enigmatic regional MioPliocene unconformity has been discovered through the interpretation of new academic and industrial datasets. The aim of this work is to describe and understand the origin of this surface. Our analysis shows that this unconformity is made of a series of valleys that cross-cut sedimentary strata. Each one of these...
Tipo: Text
Palavras-chave: Unconformity; Hydrate pockmark; Slide; Contourite; Valley; Canyon; Demerara plateau.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00271/38193/36735.pdf

Mass-transport deposits and fluid venting in a transform margin setting, the eastern Demerara Plateau (French Guiana)
Provedor de dados: 5
Autores: Pattier, France; Loncke, L.; Gaullier, V.; Basile, C.; Maillard, Alexandre; Imbert, Patrice; Roest, Walter; Vendeville, B. C.; Patriat, Martin; Loubrieu, Benoit.
The eastern Demerara Plateau offshore French Guiana was surveyed in 2003 during the GUYAPLAC cruise (multibeam bathymetry and acoustic imagery, 6-channel seismic reflection and 3.5 kHz echo-sounding). The data show the "post-transform" Cenozoic that the series located on the outer part of the plateau (below c. 2000 m) contain at least twelve stacked mass transport deposits (MTDs) that have recorded a history of large-scale slope failure, as well as two main normal fault sets that provide possible pathways for upward fluid migration through the series, reaching at high as the uppermost MTDs. Seabed data show that the area above the failures is characterized by circular-to-elongate (slope-parallel) depressions interpreted as fluid seeps (pockmarks), some of...
Tipo: Text
Palavras-chave: Fluid ascent; Pockmarks; MTDs; Transform margin; Demerara Plateau.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00157/26850/25316.pdf