Éditeur(s) : Published by Authority Published by Authority ( Nassau )
Résumé : (Internal Comments) Bahamas.
(Statement of Responsibility) Bahamas.
(Numbering Peculiarities) Volume numbering dropped, numbered within the year <1950-2003>
Description based on: Vol. 4, no. 1 (Jan. 2, 1897); title from caption.
Includes supplements, which are internumbered with issues of the gazette: part 1 contains acts, part 2 contains statutory instruments; part 3 is called journal.
Vols. for <1989-2003> have unnumbered extraordinary issues, that can contain acts, statutory instruments, or notices.
Bahamas
Bahamas
Bahamas
Bahamas

AHK7292
19872904
001583356
2004217161

Éditeur(s) : Published by Authority Published by Authority ( Nassau )
Résumé : (Internal Comments) Bahamas.
(Statement of Responsibility) Bahamas.
(Numbering Peculiarities) Volume numbering dropped, numbered within the year <1950-2003>
Description based on: Vol. 4, no. 1 (Jan. 2, 1897); title from caption.
Includes supplements, which are internumbered with issues of the gazette: part 1 contains acts, part 2 contains statutory instruments; part 3 is called journal.
Vols. for <1989-2003> have unnumbered extraordinary issues, that can contain acts, statutory instruments, or notices.
Bahamas
Bahamas
Bahamas
Bahamas

AHK7292
19872904
001583356
2004217161

Éditeur(s) : Published by Authority Published by Authority ( Nassau )
Résumé : (Statement of Responsibility) Bahamas.
(Numbering Peculiarities) Volume numbering dropped, numbered within the year <1950-2003>
Description based on: Vol. 4, no. 1 (Jan. 2, 1897); title from caption.
Includes supplements, which are internumbered with issues of the gazette: part 1 contains acts, part 2 contains statutory instruments; part 3 is called journal.
Vols. for <1989-2003> have unnumbered extraordinary issues, that can contain acts, statutory instruments, or notices.
Bahamas
Bahamas
Bahamas
Bahamas

AHK7292
19872904
001583356
2004217161

Éditeur(s) : HAL CCSD Annex Publishers
Résumé : International audience
Introduction: Shark-based ecotourism is significantly developing around the world, often without appropriate management of risk. This activity involves a risk of accidental bites on divers that can be quite severe or even fatal. Objectives: To determine if ecotourism companies' liability can be engaged in the context of bites on scuba divers in presence of hand-feeding practices, supporting the legitimacy of financial compensation for the victims. Methods: We analyzed the development from the mid-eighties to 2010 of shark-based ecotourism through artificial provisioning practices in Moorea Island (French Polynesia) and more specifically the features and motivation of two bites on divers by Sicklefin Lemon sharks. Results: The specific practice of hand-feeding can be considered as a facilitating factor for accidental bites on divers, potentially involving the diving operator's responsibility. Conclusions: Our findings should support the technical work of experts that might be called in such cases.
ISSN: 2348-9804

hal-01238771
https://hal-univ-perp.archives-ouvertes.fr/hal-01238771
https://hal-univ-perp.archives-ouvertes.fr/hal-01238771/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01238771/file/3502-Determining-the-Role-of-Hand-Feeding-Practices-in-Accidental-Shark-Bites-on-Scuba-Divers.pdf

Éditeur(s) : Published by Authority Published by Authority ( Nassau )
Résumé : (Internal Comments) Bahamas.
(Statement of Responsibility) Bahamas.
(Numbering Peculiarities) Volume numbering dropped, numbered within the year <1950-2003>
Description based on: Vol. 4, no. 1 (Jan. 2, 1897); title from caption.
Includes supplements, which are internumbered with issues of the gazette: part 1 contains acts, part 2 contains statutory instruments; part 3 is called journal.
Vols. for <1989-2003> have unnumbered extraordinary issues, that can contain acts, statutory instruments, or notices.
Bahamas
Bahamas
Bahamas
Bahamas

AHK7292
19872904
001583356
2004217161

Éditeur(s) : Elsevier
Résumé : in this study we evaluated the effects of the probiotic Pediococcus acidilactici MA18/5M on shrimp, Litopenaeus stylirostris (also called Penaeus stylirostris), first on antioxidant defences and secondly on the oxidative stress status in the shrimps' haemolymph and digestive gland. We conducted two experiments with the same protocol in which shrimps were fed two diets for three weeks: a control diet and a probiotic diet containing 1 g of live P. acidilactici MA18/5M kg(-1). In the first experiment, the shrimps were found to be healthy over the trial period; no mortalities and non-detectable signs of infection were recorded. These resulted in high final survival rates (above 90% in both treatments). On the other hand, during the second trial, carried out at a period of increased risk for an outbreak of the summer syndrome, higher mortalities were recorded, associated with high V. nigripulchritudo prevalence and loads in the shrimp haemolymph. In healthy shrimps (trial 1), no detectable response of the antioxidant defence system and of oxidative stress bio-indicators were observed. However, feeding the probiotic significantly increased the total antioxidant status (TAS) and glutathione peroxidase activity, while all other parameters remained significantly unchanged. In the shrimps exposed to V nigripulchritudo (trial 2), the antioxidant response was characterized by higher antioxidant enzyme activities (superoxide dismutase and catalase) and higher oxidative stress level in the digestive gland (higher oxidized/reduced glutathione ratio, higher malonclialdehyde and carbonyl protein contents) compared to levels found in trial 1. However, shrimps fed the probiotic diet exhibited (i) significantly higher final survival rates (67 +/- 3%) compared to the control (47 +/- 4%) and (ii) a lower prevalence of V nigripulchritudo throughout the trial. Moreover, the antioxidant response and the oxidative stress level recorded in the digestive gland with shrimps submitted to the probiotic diet were lower. In the light of these results, we confirm that P acidilactici enrichment in shrimps' diet seems an effective way of reducing the susceptibility of shrimps to bacterial pathogens. (c) 2009 Elsevier B.V. All rights reserved.
Aquaculture (0044-8486) (Elsevier), 2009-09 , Vol. 294 , N. 3-4 , P. 306-313

Droits : 2009 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/2009/publication-6780.pdf
DOI:10.1016/j.aquaculture.2009.06.016
http://archimer.ifremer.fr/doc/00000/6780/

Éditeur(s) : Published by Authority Published by Authority ( Nassau )
Résumé : (Statement of Responsibility) Bahamas.
(Numbering Peculiarities) Volume numbering dropped, numbered within the year <1950-2003>
Description based on: Vol. 4, no. 1 (Jan. 2, 1897); title from caption.
Includes supplements, which are internumbered with issues of the gazette: part 1 contains acts, part 2 contains statutory instruments; part 3 is called journal.
Vols. for <1989-2003> have unnumbered extraordinary issues, that can contain acts, statutory instruments, or notices.
Bahamas
Bahamas
Bahamas
Bahamas

AHK7292
19872904
001583356
2004217161

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Seismic anisotropy originating within the continental crust is used to determine kinematic flow lines within active mountain belts and is widely attributed to regionally aligned mica. However, naturally deformed micaceous rocks commonly show composite (e.g. S-C) fabrics. It is necessary therefore to understand how both varying mica content and differing intensities of multiple foliations impact on seismic interpretations in terms of deformation fields. An outcrop analogue for granitic mid-crustal deformed zones is used here to calibrate the seismic response against both parameters. Seismic responses are modelled using crystallographic preferred orientations for polymineralic, micaceous granitic gneisses, measured using Electron Back-Scatter Diffraction. The sample results are generalised by modelling the effects of variations in modal composition and the relative importance of deformation fabrics of variable orientation, so-called rock and fabric recipes. The maximum P- and S-anisotropy are calculated at 16.6% and 23.9% for single-foliation gneisses but for mixed (i.e. S-C) foliation gneisses these values reduce to 5.8% and 7.5% respectively. Furthermore, mixtures of multiple foliations generate significant variations in the geometry of the seismic anisotropy. This effect, coupled with the geographical orientation of fabrics in nature. can generate substantial variations in the orientation and magnitude of seismic anisotropy (especially for shear waves) as measured for the continental crust using existing receiver function and teleseismic near-vertical incidence methods. Thus, maps of seismic anisotropy varying with depth in deforming continents need not imply necessarily depth-varying deformation kinematics and tectonic decoupling.
ISSN: 0012-821X

hal-00445247
https://hal.archives-ouvertes.fr/hal-00445247
DOI : 10.1016/j.epsl.2009.09.035

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
This paper presents a reappraisal of the tectonic evolution of the Zanhuang Massif that lies at the eastern margin of the Trans-North China Orogen, a continent–continent collision belt that marked the amalgamation of the North China Craton in Late Paleoproterozoic. Detailed field work with focus on geometries of structures and kinematics was performed. This was completed with LA-ICP-MS U–Pb analyses on zircon, EPMA U–Th/Pb dating on monazite and 40Ar/39Ar dating on amphibole. These studies led us to propose a new three-fold litho-tectonic subdivision of the massif: The Western Zanhuang Domain (WZD) made of TTG, migmatite and pink anatectic granite is correlated to the Fuping Massif that crops out to the north-west. Both areas represent a continental block, called the Fuping Block, which acquired most of its architecture around 2100 Ma ago. The Eastern Zanhuang Domain (EZD) made of TTG and migmatite represents the western edge of an Eastern Neoarchean Block. In between, the Central Zanhuang Domain (CZD) is a NE–SW trending stack of supracrustal, gneiss and mafic magmatic rocks thrust sheets displaced toward the ESE upon the Eastern Block. The lithological features suggest that the CZD represents the remnant of an oceanic basin, called the Taihang Ocean that closed during the amalgamation of the Eastern Block and the Fuping Block around 1880–1850 Ma. In agreement with recent work done along the western margin of the belt, in the Lüliang Massif, this study documents the amalgamation of the North China Craton in response to the closure of two oceanic basins, namely the Lüliang Ocean and the Taihang Ocean. West-dipping subductions and collisions involving three distinct continental blocks, called the Western, the Fuping and the Eastern Blocks, took place around 1880–1850 Ma.
ISSN: 0301-9268

insu-00403871
https://hal-insu.archives-ouvertes.fr/insu-00403871
https://hal-insu.archives-ouvertes.fr/insu-00403871/document
https://hal-insu.archives-ouvertes.fr/insu-00403871/file/Trap-PrecambrianResearch-2009.pdf
DOI : 10.1016/j.precamres.2009.03.011

Éditeur(s) : Gleaner Co. Gleaner Co. ( Kingston, Jamaica )
Résumé : "Most of the following chapters first appeared in the Daily gleaner."- Pref.
A visit to Panama: p. 153-162.
(Biographical) From Wikipedia for H. G. de Lisser, from 29 June 2013: Herbert George de Lisser CMG (9 December 1878 - 19 May 1944) was a Jamaican journalist and author. He has been called "one of the most conspicuous figures in the history of West Indian literature". De Lisser was born in Falmouth, Jamaica, and attended William Morrison's Collegiate School in Kingston. He started work at the Institute of Jamaica at the age of 14. Three years later he joined the Jamaica Daily Gleaner, of which his father was editor, as a proofreader, and two years later became a reporter on the Jamaica Times. In 1903, De Lisser became assistant editor of the Gleaner and was editor within the year. He wrote several articles for the paper every day. He also produced a novel or non-fiction book every year, beginning in 1913 with Jane: A Story of Jamaica, significant for being the first West Indian novel to have a central black character. Another famous novel of his, The White Witch of Rosehall (1929), is linked to a legend of a haunting in Jamaica. De Lisser also wrote several plays. In December 1920 he began publishing an annual magazine, Planters' Punch. De Lisser devoted much time and effort to the revival of the Jamaican sugar industry and represented Jamaica at a number of sugar conferences around the world. He was also general secretary of the Jamaica Imperial Association, honorary president of the Jamaica Press Association, and chairman of the West Indian section of the Empire Press Union. He was appointed Companion of the Order of St Michael and St George (CMG) in the 1920 New Year Honours.
(Statement of Responsibility) by H. G. De Lisser.
Jamaica
Cuba
Panama

001665789
24569573
AHX7577
11027504 //r
http://ufdc.ufl.edu/UF00080939/00001

Éditeur(s) : Published by Authority Published by Authority ( Nassau )
Résumé : (Internal Comments) Bahamas.
(Statement of Responsibility) Bahamas.
(Numbering Peculiarities) Volume numbering dropped, numbered within the year <1950-2003>
Description based on: Vol. 4, no. 1 (Jan. 2, 1897); title from caption.
Includes supplements, which are internumbered with issues of the gazette: part 1 contains acts, part 2 contains statutory instruments; part 3 is called journal.
Vols. for <1989-2003> have unnumbered extraordinary issues, that can contain acts, statutory instruments, or notices.
Bahamas
Bahamas
Bahamas
Bahamas

AHK7292
19872904
001583356
2004217161

Éditeur(s) : Published by Authority Published by Authority ( Nassau )
Résumé : (Internal Comments) Bahamas.
(Statement of Responsibility) Bahamas.
(Numbering Peculiarities) Volume numbering dropped, numbered within the year <1950-2003>
Description based on: Vol. 4, no. 1 (Jan. 2, 1897); title from caption.
Includes supplements, which are internumbered with issues of the gazette: part 1 contains acts, part 2 contains statutory instruments; part 3 is called journal.
Vols. for <1989-2003> have unnumbered extraordinary issues, that can contain acts, statutory instruments, or notices.
Bahamas
Bahamas
Bahamas
Bahamas

AHK7292
19872904
001583356
2004217161

Éditeur(s) : Published by Authority Published by Authority ( Nassau )
Résumé : (Statement of Responsibility) Bahamas.
(Numbering Peculiarities) Volume numbering dropped, numbered within the year <1950-2003>
Description based on: Vol. 4, no. 1 (Jan. 2, 1897); title from caption.
Includes supplements, which are internumbered with issues of the gazette: part 1 contains acts, part 2 contains statutory instruments; part 3 is called journal.
Vols. for <1989-2003> have unnumbered extraordinary issues, that can contain acts, statutory instruments, or notices.
Bahamas
Bahamas
Bahamas
Bahamas

AHK7292
19872904
001583356
2004217161

Éditeur(s) : Published by Authority Published by Authority ( Nassau )
Résumé : (Statement of Responsibility) Bahamas.
(Numbering Peculiarities) Volume numbering dropped, numbered within the year <1950-2003>
Description based on: Vol. 4, no. 1 (Jan. 2, 1897); title from caption.
Includes supplements, which are internumbered with issues of the gazette: part 1 contains acts, part 2 contains statutory instruments; part 3 is called journal.
Vols. for <1989-2003> have unnumbered extraordinary issues, that can contain acts, statutory instruments, or notices.
Bahamas
Bahamas
Bahamas
Bahamas

AHK7292
19872904
001583356
2004217161

Éditeur(s) : Published by Authority Published by Authority ( Nassau )
Résumé : (Statement of Responsibility) Bahamas.
(Numbering Peculiarities) Volume numbering dropped, numbered within the year <1950-2003>
Description based on: Vol. 4, no. 1 (Jan. 2, 1897); title from caption.
Includes supplements, which are internumbered with issues of the gazette: part 1 contains acts, part 2 contains statutory instruments; part 3 is called journal.
Vols. for <1989-2003> have unnumbered extraordinary issues, that can contain acts, statutory instruments, or notices.
Bahamas
Bahamas
Bahamas
Bahamas

AHK7292
19872904
001583356
2004217161

Éditeur(s) : Published by Authority Published by Authority ( Nassau )
Résumé : (Internal Comments) Bahamas.
(Statement of Responsibility) Bahamas.
(Numbering Peculiarities) Volume numbering dropped, numbered within the year <1950-2003>
Description based on: Vol. 4, no. 1 (Jan. 2, 1897); title from caption.
Includes supplements, which are internumbered with issues of the gazette: part 1 contains acts, part 2 contains statutory instruments; part 3 is called journal.
Vols. for <1989-2003> have unnumbered extraordinary issues, that can contain acts, statutory instruments, or notices.
Bahamas
Bahamas
Bahamas
Bahamas

AHK7292
19872904
001583356
2004217161

Résumé : This report presents the implementation process and the current status of the marine GIS database project in Mont Saint Michel Bay, called SIMON. This document provides a user's guide for Sextant (technical platform for SIMON), describes various protocols that were developed (data validation, creation of metadata and preparation for uploading data on Sextant) and gives an inventory of data currently available in SIMON. This report is thus intended for end users but also for project coordinators, particularly those who are responsible for geomatics management using SIMON....
Ce rapport a pour objectif de présenter la démarche de mise en place et l'état d'avancement du projet de SIG marin en Baie du Mont Saint-Michel, nommé SIMON. Il propose un manuel d'utilisation de Sextant (support technique de SIMON), divers protocoles mis au point (validation des données, création des métadonnées et préparation au chargement des données sur Sextant), ainsi qu'un catalogue des données actuellement disponibles sur SIMON. Il s'adresse donc aux utilisateurs mais aussi aux porteurs du projet, notamment l'administrateur qui prendra en charge la gestion géomatique de SIMON. Ce projet a bénéficié de financements de la Délégation Interministérielle à l'Aménagement et à la Collectivité des Territoires (DIACT) via le Fond National d'Aménagement et de Développement du Territoire (FNADT), de la DIREN Bretagne et de l'Association Interdépartementale Manche Ille-et-Vilaine. SIMON est un projet de mutualisation de données, il n'aurait donc pu voir le jour sans la participation active des très nombreux producteurs de données de la baie du Mont Saint-Michel que nous remercions vivement. Nous prions ceux qui auraient été omis de la liste ci-dessous de bien vouloir nous pardonner : CELRL, DDAM 35, DDE Ille-et- Vilaine, DDE Manche, DIREN Basse-Normandie, DIREN Bretagne, DRE Bretagne, IFREMER, Maison de la baie du Mont Saint-Michel, MNHN/CNRS (Station marine de Dinard), EPHE/CNRS (Laboratoire de géomorphologie de Dinard), Université de La Rochelle, SHOM, etc...

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2008/rapport-4360.pdf
http://archimer.ifremer.fr/doc/00000/4360/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Estrogen receptors (ERs) α and β are distributed in most tissues of women and men. ERs are bound by estradiol (E2), a natural hormone, and mediate the pleiotropic and tissue-specific effects of E2, such as proliferation of breast epithelial cells or protection and differentiation of neuronal cells. Numerous environmental molecules, called endocrine disrupting compounds, also interact with ERs. Phytoestrogens belong to this large family and are considered potent therapeutic molecules that act through their selective estrogen receptor modulator (SERM) activity. Using breast cancer cell lines as a model of estrogen-dependent proliferation and a stably ER-expressing PC12 cell line as a model of neuronal differentiating cells, we studied the SERM activity of major dietary compounds, such as apigenin, liquiritigenin, daidzein, genistein, coumestrol, resveratrol and zearalenone. The ability of these compounds to induce ER-transactivation and breast cancer cell proliferation and enhance Nerve Growth Factor (NGF) -induced neuritogenesis was assessed. Surprisingly, although all compounds were able to activate the ER through an estrogen responsive element reporter gene, they showed differential activity toward proliferation or differentiation. Apigenin and resveratrol showed a partial or no proliferative effect on breast cancer cells but fully contributed to the neuritogenesis effect of NGF. However, daidzein and zearalenone showed full effects on cellular proliferation but did not induce cellular differentiation. In summary, our results suggest that the therapeutic potential of phytoestrogens can diverge depending on the molecule and the phenotype considered. Hence, apigenin and resveratrol might be used in the development of therapeutics for breast cancer and brain diseases.
ISSN: 0041-008X

hal-01558816
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01558816
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01558816/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01558816/file/Lecomte%20et%20al.%20-%20Assessment%20of%20the%20potential%20activity%20of%20major%20diet.pdf
DOI : 10.1016/j.taap.2017.04.005

Éditeur(s) : HAL CCSD Société géologique de France
Résumé : International audience
The central part of the Gulf of Lions shoreline is characterized by many coastal wetlands that resulted from the interaction between a process of shoreline regularization by migrations of littoral barriers and a slow filling of the back-barrier areas by the riverine and marine inputs. Analyses of Late-Holocene deposits with a very high-resolution multi-proxy study of two sediment cores, allow us to reconstruct the evolution of this coastal system. Two main Holocene sediment units are identified overlying a Pliocene carbonate continental formation. The lower unit consists of sandy and pebbly marine sediments deposited around 7800 B.P., during the final stand of the last sea level rise. Just above, the upper unit displays lagoonal grey clay silts with shells and some intercalated layers of silty sands related to paleostorm events. The age model was established from radiocarbon dating, for the oldest part of the core. Over the last century, sedimentation rates were calculated using the CFCS Pb-210 model, together with Cs-137 data. Radiocarbon data show an increase in he accumulation rate from the base to the top of cores. Marine sand units related to the last transgressive deposit allow to refine the curve of Holocene post-glacial sea level rise. Sedimentological and faunal analyses associated with chronological data provide a means for reconstructing the Late-Holocene paleoenvironments along this part of the coast and suggest that the final closure of the coastal lagoon by the sandy barrier occurred at around 730 +/- 120 yr cal B.P. The beginning of this closure, together with the progradation of the coastal plain, could be responsible for the decline in economic activity of the Lattara harbour during the Roman period.
La partie centrale du littoral du golfe du Lion est caractérisée par de nombreuses lagunes qui résultent de l'interaction entre un processus de régularisation du trait de côte par migration de barrières littorales et d'un lent remplissage des zones situées en arrière des barrières par des apports continentaux et marins. Les analyses des dépôts tardi-holocènes avec une étude multi-traceurs à très haute résolution de deux carottes sédimentaires nous permettent de reconstruire l'évolution de ce système côtier. Deux unités sédimentaires holocènes sont identifiées recouvrant une formation pliocène carbonatée. L'unité inférieure est constituée de sables et de galets d'origine marine déposés vers 7800 B.P., durant les stades ultimes de la dernière remontée marine. Audessus, l'unité supérieure montre des dépôts d'argile et de silt gris coquilliers d'origine lagunaire, dans lesquels sont intercalés des niveaux de sable silteux révélant la présence d'événements de tempêtes. Le modèle d'âge est établi à partir de dates radiocarbones pour les parties les plus anciennes des archives sédimentaires, tandis que pour le dernier siècle, les taux de sédimentation sont calculés en utilisant le modèle CFCS pour le 210Pb, associé aux données de 137Cs. Les données 14C montrent une augmentation du taux d'accumulation depuis la base jusqu'en surface des carottes. Les unités de sables marins liées aux dépôts de la dernière transgression marine permettent de préciser la courbe post-glaciaire de remontée du niveau marin. Les analyses sédimentologiques et faunistiques associées aux données chronologiques fournissent une méthode permettant de reconstituer les paléoenvironnements littoraux tardi-holocènes dans la zone d'étude et suggèrent que la fermeture finale de ces lagunes par le cordon sableux survient autour de 730 ± 120 ans cal B.P. Le début de cette fermeture, associée à la une progradation deltaïque, pourrait être responsable du déclin des activités économiques du port de Lattara durant la période Romaine.
EISSN: 1777-5817

halshs-00740923
https://halshs.archives-ouvertes.fr/halshs-00740923
DOI : 10.2113/gssgfbull.181.1.27

Éditeur(s) : HAL CCSD Elsevier
Résumé : The dense hydrous magnesium silicate called the D phase is the most likely candidate to recycle hydrogen into the lower mantle in subduction zones. As seismology represents the preferred method to detect this mineral in subduction zones, the single crystal elastic tensor has been calculated using first principle methods. A triple cell (View the MathML source) was used to account for an ordered ideal composition of the D phase to lower mantle pressures. The elastic tensor of the mineral at ambient conditions is predicted to be C11 = 387.7, C33 = 287.7, C44 = 100.4, C12 = 108.0, C13 = 51.1, C14 = − 14.6 in GPa with bulk modulus at zero pressure Ko = 163 GPa and a statistical error of about 4.0 GPa for all constants. The pressure derivatives of the elastic constants have been determined to pressure of 80 GPa. Our tensor correctly predicts the published experimental measurements of linear compressibility along the a- and c-axes, the logarithmic pressure derivative of the c/a axial ratio and bulk modulus at zero pressure. It contradicts the experimentally measured elastic tensor reported by (Liu, L.-G., Okamoto, K., Yang, Y.-J., Chen, C.-C., Lin, C.-C., 2004. Elasticity of single-crystal phase D (a dense hydrous magnesium silicate) by Brillouin spectroscopy. Solid State Commun. 132, 517–520), which fails to reproduce the experimental compressibility data. Using the elastic constants and density predicted to 85 GPa, the seismic anisotropy of P- and S-waves has been calculated as a function of pressure. The single crystal has high P-wave velocities and shear wave splitting in the basal plane below 20 GPa. At high pressures, the maximum P-wave velocities have threefold symmetry normal to a-axes in the basal plane, whereas the maximum shear wave splitting is parallel to a-axes with twofold symmetry. The D phase has high Vp and Vs anisotropy at ambient pressure, 17.6% for Vp and 19.9% for Vs. The Vp anisotropy decreases with increasing pressure to about 30 GPa, while it remains constant at 8% from 30 to 85 GPa. The Vs anisotropy decreases to 17% at 20 GPa and then increases to 22% at 85 GPa. The isotropic velocity ratios of S to P (Rs/p), bulk sound to S (Rphi/s) and density to S (Rρ/s) are calculated as a function of pressure. The Rs/p shows very little variation with pressure with low value of 0.6, whereas both Rphi/s and Rρ/s increase with pressure to peak values of 2.8 and 2.0 respectively at about 60 GPa. The presence of the D phase in subducted horizontal ‘stagnant' plates in the circum Pacific could contribute to a number of seismic observations, such as the observed velocity heterogeneity at depths between 500 and 1000 km and the fast S-waves travelling horizontally with horizontal polarization in this depth range. Further the lower density of the D phase compared with anhydrous minerals could influence buoyancy of the hydrated ‘stagnant' slabs. The transformation of the D phase to perovskite plus ferripericlase during thermal annealing may be responsible for horizontal slab seismogenesis.
ISSN: 0012-821X

hal-00406379
https://hal.archives-ouvertes.fr/hal-00406379
DOI : 10.1016/j.epsl.2007.04.053