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| Sultan, Nabil. |
| In the IODP 372A proposal, working hypotheses used with respect to actively deforming gas hydrate‐bearing landslides were based on an initial calculation considering gas hydrate to occur in fresh water. This initial inaccuracy leads to predict the base of methane hydrate stability zone (MHSZ) to be at around 162 meters below the seafloor (mbsf) at site U1517 while it is expected to be between 85 and 128 mbsf. It is most interesting that important negative chloride anomalies were measured well below the theoretical MHSZ without direct evidence of the presence of gas hydrate. These anomalies are usually a strong indication of gas hydrate occurrence. This initial inaccurate hypothesis provides the opportunity to evaluate the effectiveness of the indirect... |
| Tipo: Text |
Palavras-chave: Hikurangi; Hydrate; IODP; Salinity. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00628/74043/73389.pdf |
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| Sultan, Nabil; Cochonat, Pierre; Canals, M; Cattaneo, Antonio; Dennielou, Bernard; Haflidason, H; Laberg, J; Long, D; Mienert, J; Trincardi, F; Urgeles, R; Vorren, T; Wilson, C. |
| The Costa target areas exhibit the variability of slope instabilities needed to improve our understanding of sediment physical and mechanical properties in areas prone to sliding. That is why in this project, we have analysed the different slope failures events from different parts of the Costa target areas, which reflect diverse triggering mechanisms. The aim of the first part of this study was to identify the geotechnical response of the sediment to different external mechanisms (earthquake, rapid sedimentation and gas hydrate melting). We have focused on the relation between external mechanisms and the consequence change in the in-situ stress state and the physical, mechanical, and elastic properties of the sediment. In the second part of the paper, the... |
| Tipo: Text |
Palavras-chave: Slope instability; Sensitivity; Sedimentation; Hydrate; Earthquake. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-700.pdf |
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| De Prunele, Alexis. |
| The present work describes the dynamics of two pockmark areas, off West Africa. The intention is to propose two different approaches to study the relationships between fluid migration and pockmarks. The first investigated area corresponds to a pockmark cluster called Preowei, located off Nigeria. Geochemical analyses and modeling were combined with seismic data to detail the hydrocarbon migration pattern at this area, with implication on both the pockmark formation and the evolution of their morphology. The proposed interpretation seeks to identify the conceptual bases of pockmark evolution over time at this area. It is argued that the cluster has been active for at least 2700 years, and it is still at the stage of hydrate formation for some pockmarks and... |
| Tipo: Text |
Palavras-chave: Hydrate de gaz; Marge africaine; Hydrates; Gas hydrate; Pockmark; African margin; Hydrate. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00498/60936/64329.pdf |
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| Sultan, Nabil. |
| While it is well accepted that gas hydrate dissociation at the base of the Gas Hydrate Stability Zone (GHSZ) can generate high excess pore pressure and leads to sediment deformation, the consequence in terms of pore pressure of the dissolution of the gas hydrate at the top of the Gas Hydrate Occurrence Zone (GHOZ) remains neglected. The purpose of this comment on Xu and Germanovich [2006] article is to demonstrate that gas hydrate dissolution in the GHSZ may generate excess pore pressure and to point out the risk related to hydrate dissolution at the top of the GHOZ. |
| Tipo: Text |
Palavras-chave: Pore pressure; Hydrate; Dissolution; Dissociation. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2318.pdf |
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| Hill, T. M.; Kennett, J. P.; Valentine, D. L.; Yang, Z.; Reddy, C. M.; Nelson, R. K.; Behl, R. J.; Robert, C.; Beaufort, L.. |
| Marine hydrocarbon seepage emits oil and gas, including methane (approximate to 30 Tg of CH4 per year), to the ocean and atmosphere. Sediments from the California margin contain preserved tar, primarily formed through hydrocarbon weathering at the sea surface. We present a record of variation in the abundance of tar in sediments for the past 32,000 years, providing evidence for increases in hydrocarbon emissions before and during Termination IA [16,000 years ago (16 ka) to 14 ka] and again over Termination IB (11-10 ka). Our study provides direct evidence for increased hydrocarbon seepage associated with deglacial warming through tar abundance in marine sediments, independent of previous geochemical proxies. Climate-sensitive gas hydrates may modulate... |
| Tipo: Text |
Palavras-chave: Methane; Paleoclimate; Quaternary climate; Hydrate; Tar. |
| Ano: 2006 |
URL: https://archimer.ifremer.fr/doc/00234/34524/33432.pdf |
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| Pinto,Mônia Aparecida Lemos; Ambrozini,Beatriz; Ferreira,Ana Paula Garcia; Cavalheiro,Éder Tadeu Gomes. |
| Carbamazepine (CBZ), a widely used anticonvulsant drug, can crystallize and exhibits four polymorphic forms and one dihydrate. Anhydrous CBZ can spontaneously absorb water and convert to the hydrate form whose different crystallinity leads to lower biological activity. The present study was concerned to the possibility of recovering the hydrated form by heating. The thermal behavior of spontaneously hydrated carbamazepine was investigated by TG/DTG-DTA and DSC in dynamic atmospheres of air and nitrogen, which revealed that the spontaneous hydration of this pharmaceutical resulted in a Form III hydrate with 1.5 water molecules. After dehydration, this anhydrous Form III converted to Form I, which melted and decomposed in a single event, releasing isocyanic... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Carbamazepine/thermal analysis; Polymorphism; Hydrate; Dehydration. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-82502014000400877 |
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