Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Orogenic wedges locally present chaotic tectonostratigraphic units that contain exotic blocks of various size, origin, age and lithology, embedded in a sedimentary matrix. The occurrence of ophiolitic blocks, sometimes huge, in such “mélanges” raises questions on (i) the mechanisms responsible for the incorporation of oceanic basement rocks into an accretionary wedge and (ii) the mechanisms allowing exhumation and redeposition of these exotic elements in “mélanges” during wedge growth.To address these questions, we present the results of a series of analogue experiments performed to characterize the processes and parameters responsible for accretion, exhumation and tectonosedimentary reworking of oceanic basement lithospheric fragments in an accretionary wedge.The experimental setup is designed to simulate the interaction between tectonics, erosion and sedimentation. Different configurations are applied to study the impact of various parameters, such as irregular oceanic floor due to structural inheritance, or the presence of layers with contrasted rheology that can affect deformation partitioning in the wedge (frontal accretion vs basal accretion) influencing its growth. Image correlation technique allows extracting instantaneous velocity field, and tracking of passive particles. By retrieving the particle paths determined from models, the pressure-temperature path of mélange units or elementary blocks can be discussed. The experimental results are then compared with observations from ophiolite-bearing mélanges in Taiwan (Lichi and Kenting mélanges) and Raman spectroscopy of carbonaceous material (RSCM) Thermometry data on rocks from the northern Apennines (Casanova mélange). A geological scenario is proposed following basic observations. The tectonic evolution of the retroside of doubly vergent accretionary wedges is mainly controlled by backthrusting and backfolding. The retro wedge is characterized by steep slopes that are prone to gravitational instabilities. It triggers submarine landslides inducing huge mass transfers. This erosion combined with backthrusting could favour exhumation of the ophiolitic fragments formerly accreted at the base of the wedge along the rough seafloor-sediments interface. Such an exhumed material can be reworked and deposited as debris- flows in proximal basins located at the foot of the retrowedge slope forming a tectono-sedimentary mélange. These syntectonic basins are continuously deformed and involved in prograding backthrusting-induced deformation.
ISSN: 0264-3707

hal-01395127
https://hal.archives-ouvertes.fr/hal-01395127
DOI : 10.1016/j.jog.2016.05.008

Éditeur(s) : Société des Sciences Naturelles de la Charente-Maritime
Résumé : The authors list the records of each species of fishes, probably originated in the tropical waters, unkwon before 1950 at the north of Portugal: Zenopsis conchifer, Cyttopsis roseus, Chaunax spp, Sphoeroides pachygaster, Tarpon atlanticus, Hoplostethus cadenati, Allocyttus verrucosus, Dibranchus atlanticus, Seriola rivoliana, Seriola dumerili, Seriola carpenteri, Lichia amia, Pomatomus saltator, Aluterus monoceros. NOT CONTROLLED OCR
Les auteurs répertorient espèce par espèce les signalements des poissons à affinités tropicales, inconnus avant 1950 au nord du Portugal: Zenopsis conchifer, Cyttopsis roseus, Chaunax spp, Sphoeroides pachygaster, Tarpon atlanticus, Hoplostethus cadenati, Allocyttus verrucosus, Dibranchus atlanticus, Seriola rivoliana, Seriola dumerili, Seriola carpenteri, Lichia amia, Pomatomus saltator, Aluterus monoceros. OCR NON CONTRÔLE
Annales de la Société des Sciences Naturelles de la Charente-Maritime (Société des Sciences Naturelles de la Charente-Maritime), 1997-06 , Vol. 8 , N. 6 , P. 651-673

Droits : 1997 Société des Sciences Naturelles de la Charente-Maritime
http://archimer.ifremer.fr/doc/1997/publication-3756.pdf
http://archimer.ifremer.fr/doc/00000/3756/

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
ISSN: 0049-6979

halshs-00681736
https://halshs.archives-ouvertes.fr/halshs-00681736

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
A thorough phytochemical study of Stereocaulon evolutum was conducted, for the isolation of structurally related atranorin derivatives. Indeed, pilot experiments suggested that atra-norin (1), the main metabolite of this lichen, would interfere with the lifecycle of hepatitis C virus (HCV). Eight compounds, including one reported for the first time (2), were isolated and characterized. Two analogs (5, 6) were also synthesized, to enlarge the panel of atra-norin-related structures. Most of these compounds were active against HCV, with a half-maximal inhibitory concentration of about 10 to 70 µM, with depsides more potent than monoaromatic phenols. The most effective inhibitors (1, 5 and 6) were then added at different steps of the HCV lifecycle. Interestingly, atranorin (1), bearing an aldehyde function at C-3, inhibited only viral entry, whereas the synthetic compounds 5 and 6, bearing a hydroxy-methyl and a methyl function, respectively, at C-3 interfered with viral replication.
ISSN: 1932-6203

hal-01134343
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01134343
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01134343/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01134343/file/Depsides-PloS.pdf
DOI : 10.1371/journal.pone.0120405